Imperial or metric?

[Joseph Doyle]

For those of you in the US, do you measure using an imperial ruler or tape, or go with metric?

Having grown own up with imperial, I can visualize a project that calls for a piece that is 8 inches long, as well as 5 feet 8 inches long. However, having to add something like 2 5/12 inches to 3 7/8 inches makes me head spin. This is where is see the metric system making a ton of sense.

So, what do you all do?

[Shawn Pixley]

I grew up with both imperial and Metric. I can use either. I typically use imperial as that is what the tools around here are found. There are pros and cons to both (or maybe it is always a compromise). Neither work well when dividing by 3.

[Dave Beauchesne]

As a 55 year old brought up through to grade 11 or 12 with the Imperial system, I continue to use Imperial.
Metric doesn't do it for me, but on paper, I can see its advantages.
Dave B

[Frederick Skelly]

I grew up with both imperial and Metric. I can use either. I typically use imperial as that is what the tools around here are found.

+1. I'm comfortable in either but use imperial.

[William Adams]

If you need to divide Imperial measures by three which are too fine to do so nicely, get a DTP pica/points ruler (6 picas per inch, 12 points per pica, makes it simple to divide to 1/72nd of an inch) — don’t get an old printer’s rule though, they use measures such as 72.27 points per inch, depending on country of origin.

[Jim Koepke]

Most of my work is in inches and feet. I may have a ruler that has divisions of 1/12". Twelfths of an inch are not a regular designation used in most common drawings. It is usually architectural drawings that use a scale of 1" = 1'.

I have used metric. Mostly when working on vehicles.

If one really wants to get on without it mattering, use a story stick and stop worrying about putting numbers on the measurements.

jtk

[ken hatch]

I went totally metric in my shop several years ago, first few months I had to mentally convert back and forth but that need soon went away. The biggest advantage is far, far fewer measuring mistakes are made, I can't think of the last time I screwed up a measurement. Back in the foot, yard, and stone days I made 'em almost daily. Fractional vs. metric tools really make no never mind, if you use a metric chisel to chop a mortise you mark the tenon off the chisel, mixed tools have never been a problem.

ken

[Jim Davis]

I'm sure I could cut on the wrong side of 40mm as easily as on the wrong side of 36". Metric is a the creation of a problem to serve as a solution to a problem that did not exist.

[Charles Wiggins]

Imperial. Millimeters don't seem precise enough to me and I don't know that I've ever seen a metric rule marked in smaller increments.


https://www.youtube.com/watch?v=kkKOgs7Tdzw

[Kees Heiden]

I'm sure I could cut on the wrong side of 40mm as easily as on the wrong side of 36". Metric is a the creation of a problem to serve as a solution to a problem that did not exist.

Oh yes, the problem does exist! I face it every time I'm trying to communicate a measurement on this forum. The USA is the last country in the world using imperial. So, as long as you recognise that the world is larger then good old America, then you have to acknowledge that there is a problem.

[ken hatch]

Imperial. Millimeters don't seem precise enough to me and I don't know that I've ever seen a metric rule marked in smaller increments.



Charles,

http://i257.photobucket.com/albums/hh222/VTXAZ/mmRule151117_zpsgf0dcjhw.jpg

Now you have seen two. Those were just the ones that were handy when I walked up to the bench, there are many more in the shop.

Let's see, 0.5mm is about 0.02". 0.02" is a good bit less than 1/32", is that precise enough for you?:D

ken

[ken hatch]

Kees,

What's ironic is even Imperial UK for the most part has gone metric, although the in-laws still give their weight in stones.

I drive to work on I-19 which is the only metric signed road in the USA and every time I do it is a reminder of a missed opportunity.

ken

[Charles Wiggins]

The USA is the last country in the world using imperial.

All the more reason to stay that way.

Actually, if you want to get technical, the U.S.A uses "United States customary units" which in most cases is nearly identical to Imperial, but Imperial is the old British standard.

[Charles Wiggins]

Let's see, 0.5mm is about 0.02". 0.02" is a good bit less than 1/32", is that precise enough for you?

Touché Pussy Cat! Still, I guess it's all in what you're used to. I learned far more about fractions and decimals from woodworking than I ever did in math class.


https://www.youtube.com/watch?v=DPBAX9IuVvA

[Nicholas Lawrence]

Oh yes, the problem does exist! I face it every time I'm trying to communicate a measurement on this forum. The USA is the last country in the world using imperial. So, as long as you recognise that the world is larger then good old America, then you have to acknowledge that there is a problem.

So I guess the two types of measurement systems would be the one that worked well enough to send a man to the moon, and then metric. I'm having trouble seeing the problem.

[Jim Koepke]

So I guess the two types of measurement systems would be the one that worked well enough to send a man to the moon, and then metric. I'm having trouble seeing the problem.

There are likely a lot of people in the same boat as me. All of my life it has been inches, feet, yards and miles. It has worked fine and worked for those before us.

The battle to go metric has been a long one here in the United States:


In 1866, Congress authorized the use of
the metric system in this country and supplied
each state with a set of standard metric weights
and measures.

There was actually some use before that time by government agencies:


In the early 1800's, the
U.S. Coast and Geodetic Survey (the
government’s surveying and map-making agency)
used meter and kilogram standards brought from
France.

For some reason it has never been fully adopted in the United States. Though now in stores many of our soft drinks and bottled spirits are sold in metric units.

Just the same, other than my automotive tools, almost everything in my shop is measured in inches. Of all my drill bits only one is metric. It would be kind of neat to have sets of metric auger bits and dowel forming plates.

I do have a set of metric blades for the Record equivalent to the Stanley #45.

All my lumber tends to be in inch sizes. Though it seems plywood has gone metric its labeling is still in inches. I have seen 15/32" plywood which happens to be the same as 12mm.

I have a nice (Snap-On, if my memory is working) socket that came to me from an old time mechanic that is 15/32". He likely bought it before there were many metric tools in North America.

Now when I work on my truck it takes a combination of Imperial and metric tools to get the job done. Lucky for me all my cars were VWs in my youth so I have a set of metric tools to go along with my SAE tools. (Society of American Engineering for those who are scratching their heads.)

jtk

[Shawn Pixley]

I'm sure I could cut on the wrong side of 40mm as easily as on the wrong side of 36". Metric is a the creation of a problem to serve as a solution to a problem that did not exist.

Not true in anything scientific. Metric is vastly more convenient in that usage. It may not matter much in woodworking, but overall, metric is a system that makes much more sense.

[Mel Fulks]

Boy,this is a perennial favorite! Like Nicholas I don't see any problem. Those of us who prefer imperial also learned metric and must at times use it. But I don't like it. For whatever reason,computers I guess, metric seems to have lost some increments. Seems everything is milimeters or kilometers ...so every counter top is thousands of millimeters long ...and you have to drive twice as far to deliver it.

[David C. Roseman]

So I guess the two types of measurement systems would be the one that worked well enough to send a man to the moon, and then metric. I'm having trouble seeing the problem.

No problem as long as everyone is using the same one. ;)

http://www.cnn.com/TECH/space/9909/30/mars.metric.02/

[Stew Denton]

Hi All,

Having worked extensively with both systems for my entire adult life, read that "earning a living", I know both reasonably well, but do not know every detail of either. For practical wood working there may not be a lot of practical differences that I can guess. Admittedly, as pointed out above, which ever system you know, if you only know one, is easier. I can say that if you do a lot of complex sizing with several pieces that are fractions of an inch, (or millimeters and smaller), the metric system is easier to do the calculations in.

For scientific calculations, the metric system is drastically easier. Back when studying physics, it was so much easier to do the calculations in the metric system that when given a problem in the English system, some of the guys would convert all of the parameters to the metric system, do the problem, and then convert the answer back into the English system to give the answer in the English values.

One of the big disadvantages of the English system is when you get into details that most folks don't deal with. For example, if you are working with small units of measure in the English system, and have to convert to bigger values, or vice versa, it is much more complex than the metric system. For example 0.35 kilograms is 350 grams. But to convert 4 ounces to grains, it can't be done in your head, well actually it can, as the answer is 1750 grains, but if you had to convert 3.3 ounces into grains, it become a lot more complex.

Excel and similar programs have made it a lot easier to work with the English system, for example when I work with fractions of an inch in Excel, I normally convert fractions to decimals, do the math using Excel with the decimal equivalents, and when I get done, convert the figures back into fractions of an inch. Back when I worked with slide rules and log tables, working with fractions of an inch was more time consuming.

Another example, if you work with land, and have to know and work with feet, yards, rods and chains, as units of length, which you do in the English system, the calculations are more complex than the metric system.

At any rate, for most things folks do, it probably doesn't make any difference.

Just my two bits.

Stew

[Stew Denton]

Hi Nicholas,

I do have to add one thought. The fittings that made the rockets that went to the moon were almost certainly English, but most of the basic physics and chemistry discoveries that made the trip possible were made using the metric system.

Stew

[ken hatch]

No problem as long as everyone is using the same one. ;)

http://www.cnn.com/TECH/space/9909/30/mars.metric.02/

Thanks,

Ain't that the truth.

I had just deleted a reply pointing that out because I thought the post might have offend some delicate fee fees. We in the States do some thing very well, some not so well. Sticking with fractional measurement when the rest of the world is metric is one of the not so good. Bottom line metric is a better system because it is the world standard.

As another example of how we would all be better off if we worked with the same system as the rest of the world. The one place I know where feet and nautical miles rule around the world is aviation. The only exceptions are Russia, China and some of their satellites. Russian and Chinese airspace is controlled in metric units, flying into either if you had not been in awhile was like monkey's and a basketball.

ken

[Stewie Simpson]

Dead or slow moving stock is a capital cost burden that cannot be maintained if you wish to remain a competative business. The demand from countries outside the USA willing to accept importing goods based on imperial measurement will continually decline. IMO.

[Jim Davis]

Kees,

What's ironic is even Imperial UK for the most part has gone metric, although the in-laws still give their weight in stones.

I drive to work on I-19 which is the only metric signed road in the USA and every time I do it is a reminder of a missed opportunity.

ken

Road signs in America that are not metric indicate whole miles or tenths of miles. How is metric easier? It's an example of confirmation bias.

Might be worth remembering that Germany and Japan were using metric and the US was using SAE during WWII...Must have not been a great advantage to use metric.

[Mike Cherry]

I don't know anything about sending people to the moon, other than that movie The Martian was pretty good. That was Mars...anyways. As far as my woodworking is concerned I use relative dimensioning for almost everything. I think I could make the switch to metric. Wasn't it President Ford that declared the metric system our primary system? What was that 40 years ago? Lol

[Shawn Pixley]

Road signs in America that are not metric indicate whole miles or tenths of miles. How is metric easier? It's an example of confirmation bias.

Might be worth remembering that Germany and Japan were using metric and the US was using SAE during WWII...Must have not been a great advantage to use metric.

That is a specious argument. No one claims that metric will change the world. Somehow I doubt that the war was in the hands of those devising measuring systems. Furthermore, the A-Bomb was most assuredly developed using metric calculations for the physics.

Using the same logic, "I have been carrying this magic rock that will protect the earth against asteroid extinction since 1999. We haven't been wiped out yet. QED."

Correlation is not causation

[ken hatch]

There are likely a lot of people in the same boat as me. All of my life it has been inches, feet, yards and miles. It has worked fine and worked for those before us.

The battle to go metric has been a long one here in the United States:



There was actually some use before that time by government agencies:



For some reason it has never been fully adopted in the United States. Though now in stores many of our soft drinks and bottled spirits are sold in metric units.

Just the same, other than my automotive tools, almost everything in my shop is measured in inches. Of all my drill bits only one is metric. It would be kind of neat to have sets of metric auger bits and dowel forming plates.

I do have a set of metric blades for the Record equivalent to the Stanley #45.

All my lumber tends to be in inch sizes. Though it seems plywood has gone metric its labeling is still in inches. I have seen 15/32" plywood which happens to be the same as 12mm.

I have a nice (Snap-On, if my memory is working) socket that came to me from an old time mechanic that is 15/32". He likely bought it before there were many metric tools in North America.

Now when I work on my truck it takes a combination of Imperial and metric tools to get the job done. Lucky for me all my cars were VWs in my youth so I have a set of metric tools to go along with my SAE tools. (Society of American Engineering for those who are scratching their heads.)

jtk

Jim,

Congress passed the Metric Conversion Act of 1975 "to coordinate and plan the increasing use of the metric system in the United States". Voluntary conversion was initiated, and the United States Metric Board (USMB) was established for planning, coordination, and public education. The USMB was disbanded in the autumn of 1982.* I seem to remember something happening in 1980 that led to the board disbanding.

ken

*From Wikipedia

[ken hatch]

That is a specious argument. No one claims that metric will change the world. Somehow I doubt that the war was in the hands of those devising measuring systems. Furthermore, the A-Bomb was most assuredly developed using metric calculations for the physics.

Using the same logic, "I have been carrying this magic rock that will protect the earth against asteroid extinction since 1999. We haven't been wiped out yet. QED."

Correlation is not causation

Thank you Shawn,

I started to respond, then thought "naw, not worth the effort."

ken

[Mike Holbrook]

As more and more general information references via metric, I give more and more consideration to switching. Certainly it is irritating to mentally try and convert metric to imperial in ones head as more and more things are referenced in metric. I am looking for a good metric tape measure, hoping it will help me start picturing things metrically.

I don't see this issue going away. It will continue to plague us until we finally switch. In my humble opinion, we will continue to struggle with conversions until we accept what has become the international standard. I do not care much for the argument that we should remain different, as this argument seems to argue for accentuating our differences with other people rather than celebrating and promoting similarities and learning to work more closely together.

[Mike Cherry]

I agree Mike. As I get more and more interested in Japanese hand tools, I feel myself gravitating towards metric when needed. It would be nice to not have to be different than everyone else.

[Bill McNiel]

I've gone almost totally metric in the last year, my most trusted tape measure has both systems. I've found it easier to divide metric numbers and a millimeter is more accurate than 1/16". Much easier to figure proportions/dimensions when converting preliminary sketches to shop drawings.

BTW-kudos to Shawn P for his well reasoned and articulate responses!

[Stewie Simpson]

With the ever increasing reliance on overseas manufacturers such as China and India, and other 3rd world nations to supply our goods and services; whether we like it or not, they will have a controlling influence on the future availabilty of the imperial measurement. IMO

[Derek Cohen]

I think one has to be conversant with both systems of measurement. This is especially so if you use vintage handtools (of any origin) or tools made in the USA. I also tend to purchase Imperial sizes, such as a recent purchase of forstner bits (which I could get through Lee Valley but not in Oz, where these are available only in Metric). The reason for Imperial bits is to "fit" with my Imperial blades (e.g. chisels and plough plane), where they may be used together. Ironically, most screws and bolts sold in Australia are Imperial! Go figger.

One might argue that the notion of Imperial sizing for blades (especially chisels) is not relevant. However it is when one "slaves" tools and the common denominator is Imperial.

I grew up with both systems. Metric arrived when I was 10 years old. Metric was certainly easier to use at school (anyone who has ever had to calculate Pounds, Shillings and Pence would understand this). However, when it came to practical tasks, such as measuring with a tape or rule, both systems had a special place for me, and this continues to the present.

The advantage of Imperial is when measuring longer lengths. It is easier to visualise 12" than 30mm. Actually, that is not too hard. What about 27" versus 685mm? At this distance, Metric becomes overwhelming. By contrast, when small dimensions are needed, it is much easier to see 4mm than a heavy 5/32". And then when it comes to dividing inches, especially those that include a fraction, well good luck - I'd rather use Metric.

So what happens is that I use the two systems side-by-side. My drawings and scribblings mix Imperial and Metric freely at the same time. Once one gets going in a build, however, it is irrelevant since I do not use measurements to mark dimensions, but story sticks.

Regards from Perth

Derek

[Kees Heiden]

68.5 cm, what's overwhelming about that?

A funny story about this issue. I was on a skiing trip in the Canadian backcountry one winter. I have a digital altimeter and had to set it to feet, instead of meters. All went well and on return to Holland I of course didn't use the altimeter (Holland is flat as a pancake) and forgot about it. Next summer we went to the Alps and I found that the altimeter was still set in feet. And of course I couldn't remember the magic button sequence to set the units. This was before the days of easy internet acces, so I had to go to a nearby town into a sport shop who sold the same brand and ask for help.

[Stewie Simpson]

This will cheer you up Kees.

https://www.youtube.com/watch?v=_ZI_aEalijE

[Kees Heiden]

:)


----------------------

[Trevor Goodwin]

Here in Australia just about every tool/accessory you buy is in metric, even when imperial makes more sense. Sanding belts, for instance, are given in stupid measurements like 75 x 533mm, when really its exactly 3" x 21". They often ignore the first decimal place, so a 1/2" chisel, rebadged in metric, is either 12mm or 13mm when really it is halfway between.

[William Adams]

Agree w/ Derek, but have a solution to needing to divide smaller lengths — as I noted in my previous response, get a DTP point/pica ruler which uses 1/72 inch points — it’s finer and more accurate than millimeters, and perfectly lines up w/ inches.

Above all, it avoids some of the crazy fractional metrics units which I see at work when metric page layouts come in w/ three and five or six column layouts (even simple two column layouts can have bizarre values for the gutter), and as Trevor noted, discarding a fraction of a millimeter is the difference between being half half correct (it should actually be 12.75mm, right?) or no.

[Curt Harms]

Here in Australia just about every tool/accessory you buy is in metric, even when imperial makes more sense. Sanding belts, for instance, are given in stupid measurements like 75 x 533mm, when really its exactly 3" x 21". They often ignore the first decimal place, so a 1/2" chisel, rebadged in metric, is either 12mm or 13mm when really it is halfway between.


Sort of like "3/4" inch plywood which is really 18mm? It's certainly easier to manipulate number in metric than fractions but with materials, fasteners and tools predominantly imperial here is the U.S. working in metric has its challenges.

[Trevor Goodwin]

Sort of like "3/4" inch plywood which is really 18mm? It's certainly easier to manipulate number in metric than fractions but with materials, fasteners and tools predominantly imperial here is the U.S. working in metric has its challenges.

I've seen various 3/4" tools and materials labelled 18, 19, and 20mm. It is really close to 19mm but I guess some people prefer the look of even numbers.

[Pat Barry]

It makes no difference in the process or result which measurement system you use.

[glenn bradley]

Wow, I didn't know people were so passionate about this. I was raised with both and can use either. It is certainly easier to state 12mm as being the next step up from 11mm than to say that 15/32" is the next step up from 7/16" (or whatever the granularity). I have worked, thought and dreamed in binary, octal, decimal and hex for over 30 years. I stick to imperial in the shop because it seems to relax me. Maybe it uses a different part of the brain :D:D:D.

[Warren Mickley]

The metric system was developed for chemistry, physics, astronomy; inches and feet were developed for woodworking. A foot divides very neatly into halves, thirds, fourths, sixths, eighths and twelfths. One inch makes a nice standard thickness for a board; one foot a nice standard width. Much more convenient. Frankly if we did not have ten fingers no one would have ever picked base ten for a system. Many historical systems use twelve despite the fact that you couldn't count it on your fingers. Older incheswere divided into lines, twelfths, for easy division into thirds.

This reminds me of a little story. My neighbor's daughter broke her leg and the doctor told him he put a 30 cm rod in her bone. The neighbor said "I'm a carpenter can you put that in inches."
Doctor:"It's about a yard"
Carpenter: A yard! It can't be that long."
Doctor:" She has really long legs."

That evening the carpenter took out a yardstick and held it against his leg before calling me up.

[lowell holmes]

I've gone almost totally metric in the last year, my most trusted tape measure has both systems. I've found it easier to divide metric numbers and a millimeter is more accurate than 1/16". Much easier to figure proportions/dimensions when converting preliminary sketches to shop drawings.

BTW-kudos to Shawn P for his well reasoned and articulate responses!

Are your drill augers and chisels imperial or metric.

I know without looking that there are 25.4mm in an inch, but I see no reason to go metric when my lumber and tools are imperial.
I will not go metric just to be clever.

[Rob Luter]

I use Imperial, but do everything in decimal inches. Working as an Engineer for the last 35 years, I've managed to commit all the decimal equivalents to memory. The math is much easier to do in your head.

[Mel Fulks]

Mike, I think you are right and congress passed a law to go all metric in 1966....or about. Complete date NOT start date
Done deal. And I have seen the nutty drawings with measurements like "6432 MILLIMETERS" to prove it. So all you have to do is translate it to something that makes sense and move forward...after shouting oaths and obscenities....which sound better than Muzak ..

[Jim Davis]

That is a specious argument. No one claims that metric will change the world. Somehow I doubt that the war was in the hands of those devising measuring systems. Furthermore, the A-Bomb was most assuredly developed using metric calculations for the physics.

Using the same logic, "I have been carrying this magic rock that will protect the earth against asteroid extinction since 1999. We haven't been wiped out yet. QED."

Correlation is not causation


The war against Germany was won because the U.S. out-produced weapons and equipment.

I didn't say metric lost the war for the Axis powers. I just said it was not an advantage that saved them. Wood chips can end up on shoulders. Metric is not a great advantage. Even if it were, easier is not always better. That's why this forum exists. If we always chose easier, we would not use hand tools.

[john zulu]

Wood working is the only interest I went imperial. Partly due to the tools I get from the west are in imperial...... The rest of my interest like metal working I use metric. From Malaysia

[Jim Davis]

I probably have an unreasonable aversion to metric because of the arrogance of its origins. The meter was intended to be one ten-millionth of the the distance from the equator to the north pole along a meridian that runs through Paris. But it was not known that the earth is not truly round, so the calculated length of the meter did not conform to the ration. After this was discovered, it was suggested that the meter be changed to equal 40 inches instead of 39.37 inches, resulting in an exact ratio with the inch/foot/yard. But NO! The meter was already sacred.

Ever since, the metric backers have been touting the supremacy of a system that is not related to the size of a king's foot, thumb joint, or the length from elbow to finger tip. But when we say a fish was a foot long, it instantly brings a rather accurate image to mind. If we say 30 centimeters long, our mind (if we are fluent with metric units) says, huh, that's a little longer than my foot.

[Mel Fulks]

Jim ,informative and well stated. Love the fish example, I agree. If someone says they caught a fish a foot long....
it instantly brings up the image of a fish between 8 and 10 inches.

[Shawn Pixley]

The war against Germany was won because the U.S. out-produced weapons and equipment.

I didn't say metric lost the war for the Axis powers. I just said it was not an advantage that saved them. Wood chips can end up on shoulders. Metric is not a great advantage. Even if it were, easier is not always better. That's why this forum exists. If we always chose easier, we would not use hand tools.

You are welcome use any measurement system you want. Metric is a great advantage in all scientific endeavors, just not woodworking. My point was any argument that uses WWII to defend a measurement system is a very long stretch that strain credulity.

[Andrey Kharitonkin]

I use Imperial, but do everything in decimal inches. Working as an Engineer for the last 35 years, I've managed to commit all the decimal equivalents to memory. The math is much easier to do in your head.

Prefer centimeters and millimeters. Otherwise, decimal inches is my preferred way also! I remember that 1/8 = 0.125 because of vine glasses, and that is around 3 mm. Monitor sizes I can comprehend only in inches. Looks strange when German advertisements have written them in cm. Bandsaw sizes are nice in inches. Human height is not nice in inches (184 cm = 72.44 inch or 6'-440/1000").

I find that useful measurements are easier in metric. For example, how to center 3/8 hole in 2-5/32 wide plank? Deduce one from another and divide by two - that will be the offset from both sides. Will never use imperial for that. Or when some sizes increase slightly - it was 2-1/16 now it is 2-3/32.

For me Imperial system work fine for something made in fixed increments, like monitors and saw blades, or when without fractions, like 1,8 miles.

But that is only brain training, which is a good thing. Having bolts and nuts in two different systems is simply expensive. Had to buy Imperial tools like sockets and hex bits when I bought some products from Incra and Veritas and Benchcrafted. That is not merely brain exercise!

But at least now I know why there are some odd sizes in Metric world. Like kitchen countertop is usually 38 mm thick (1-1/2"), particle panels are 19 mm thick (3/4"), holes in the walls for power outlet are 68 mm round and so on.

Salut from metric guy!

[Jim Koepke]

I find that useful measurements are easier in metric. For example, how to center 3/8 hole in 2-5/32 wide plank? Deduce one from another and divide by two - that will be the offset from both sides. Will never use imperial for that. Or when some sizes increase slightly - it was 2-1/16 now it is 2-3/32.

For me it is easier and more accurate to do this via mechanical means. Using either dividers, a marking gauge or even a ruler held at a diagonal will seldom introduce a math error.

jtk

[Daniel Rode]

I use imperial measurements exclusively for woodworking. That's what I grew up with and what I'm familiar with. For me, I can look at a bolt and know it's 3/8" or a board a know it's a 1 x 6. I can spot 8' or 40' by eye. I can't tell what metric size something is without measuring. In addition, tools and supplies are generally imperial.

Metric is a well thought out system but it never fully displaced imperial here in the states. In woodworking and the trades, imperial remains the norm.

However...

I can't buy a liter of milk at the grocery store but I can get a 2 liter of fizzy sugar water. As for wrenches, I need full sets of both. It's not uncommon to have a mix of each. One part metric, one part imperial. And what about marathons? 26.2 miles (based on Pheidippides run from Marathon to Athens) and often connected with 1/2 marathon and 5k and 10k races.

Goofy world we live in...

[Bill McNiel]

My drills are Imperial, chisel are primarily Imperial with some Bench and Paring Metric "infills", full sets of wrenches and sockets in both I & M.

Not at all sure what the choices have to do with being "clever", although I have always considered such a designation a compliment.

[Greg Krummel]

When I'm woodworking, machining, or designing, U.S. customary units are more convenient. If I need to cut or use a tool in half or double increments, it's easier in base 2 fractions than decimal places. If I need a more accurate measurement, calipers and other measurement tools with thousandths of an inch work well. As many have pointed out, the materials and tooling supplied in the U.S. are primarily in customary units, so it's convenient to also work in the native units.

When I'm doing scientific calculations for research, metric is just more consistent, well established, and widely accepted. Also, scientific standards agencies in the U.S. have switched to metric.

[Paul Sidener]

Oh yes, the problem does exist! I face it every time I'm trying to communicate a measurement on this forum. The USA is the last country in the world using imperial. So, as long as you recognise that the world is larger then good old America, then you have to acknowledge that there is a problem.

I was a printer for 30 years. Used equipment that was made in Germany, it was all metric. I have no problem using either. I don't see what the problem is. You are from a different country, and speak a different language. Yet we have no problem communicating. I don't see anyone saying the world must speak only one language. Most people in Europe speak more than one language.

Measurements are just numbers. What difference does it make, how someone measures? It is the final product that matters anyways. Most people wouldn't know if something was made in metric or imperial anyways. I try to measure as little as possible. I find, I make less mistakes that way. My old shop teacher used to say measure twice cut once. To me that gives me twice as many chances to make a mistake. I just don't see the problem. To each their own.

What do you call someone that is bilingual? An Englishman.
What do you call someone that speaks three languages? a Frenchman.
What do you call someone that speaks only one language? An American.

I am bilingual. I speak good english and bad english, and understand very little of either.

[Mike Cherry]

For me it is easier and more accurate to do this via mechanical means. Using either dividers, a marking gauge or even a ruler held at a diagonal will seldom introduce a math error.

jtk
Totally agree Jim. This is one of the best tips I get from watching other craftsman work. Watching Paul Sellers find the center of a boards width by trying his marking gauge from both sides until the pin is in the same spot. Presto, you just found center. I think these type of tricks or whatever you call them are the golden nuggets of watching others work.

[Joel Thomas Runyan]

Linear measurement with the imperial system is mostly disagreeable because of the inconsistency in unit division, but this is more less unimportant as concerns furniture construction, as anything furniture sized can be measured in a reasonable number of inches.

The question is one of base. The Base 10 of metric is actually quite poor for general calculation... it only seems convenient because we count in decimal. If we counted in hexadecimal, all the imagined strength of millimeters could be given to inches. Unfortunately, we're never going to start counting in hexadecimal, so it's currently the most convenient to calculate in metric. In a strange turn of events, metric lovers insist on giving grief to the imperialists for being stuck in illogical and antiquated ways, when in reality, counting in 10s is about as arbitrary as it gets.

[Kees Heiden]

I was a printer for 30 years. Used equipment that was made in Germany, it was all metric. I have no problem using either. I don't see what the problem is. You are from a different country, and speak a different language. Yet we have no problem communicating. I don't see anyone saying the world must speak only one language. Most people in Europe speak more than one language.

Measurements are just numbers. What difference does it make, how someone measures? It is the final product that matters anyways. Most people wouldn't know if something was made in metric or imperial anyways. I try to measure as little as possible. I find, I make less mistakes that way. My old shop teacher used to say measure twice cut once. To me that gives me twice as many chances to make a mistake. I just don't see the problem. To each their own.

What do you call someone that is bilingual? An Englishman.
What do you call someone that speaks three languages? a Frenchman.
What do you call someone that speaks only one language? An American.

I am bilingual. I speak good english and bad english, and understand very little of either.

Yes I understand that it isn't a problem for you when I write English and use imperial measurements. :D

[Johannes Becker]

10 fingers may have something to do with that. Now that is somewhat arbitrary I guess. Interesting question for a biologist.

[Pat Barry]

The question is one of base. The Base 10 of metric is actually quite poor for general calculation... it only seems convenient because we count in decimal. If we counted in hexadecimal, all the imagined strength of millimeters could be given to inches. Unfortunately, we're never going to start counting in hexadecimal, so it's currently the most convenient to calculate in metric. In a strange turn of events, metric lovers insist on giving grief to the imperialists for being stuck in illogical and antiquated ways, when in reality, counting in 10s is about as arbitrary as it gets.
This is bizarre. Perhaps you can explain why we should switch to hexadecimal

[Kees Heiden]

The inch is dived in 16ths (or 32s or 64ths). The feet is divided in 12 inches. The yard in 3 feet. The mile in 1760 yards, which is 110 x 16. The gallon is 57.75 cubic inches.

I have difficulty to find a rythm in these numbers.

[Daniel Rode]

Metric is A designed base 10 system. Base 10 is convenient as it's our primary system for doing math. Sort of. Time and dates are base 6. Should we switch to a superior base 10 system. 10 months in year, 10 weeks in a month, 10 days in a week, 10 hours, minutes, seconds... Perhaps we could introduce a 5th season to help the system work. Imperial is, to a large degree, a system of measurements that evolved over time. Metric, wile quite rational, is not objectively superior is just more common and perhaps requires less mental effort. The world turned before imperial or metric existed.

Also, it's a misunderstanding that an imperial inch is divided by 16ths, 32nds, etc. It is a progression by halves and has an obvious rhythm.

To further confuse things, in the US we don't actually use the imperial system. For example a US gallon and an imperial gallon are different.

[Stewie Simpson]

In 1790, in the midst of the French Revolution, the National Assembly of France requested the French Academy of Sciences to "deduce an invariable standard for all the measures and all the weights."

The Commission appointed by the Academy created a system that was, at once, simple and scientific. The unit of length was to be a portion of the Earth's circumference. Measures for capacity (volume) and mass were to be derived from the unit of length, thus relating the basic units of the system to each other and to nature. Furthermore, larger and smaller multiples of each unit were to be created by multiplying or dividing the basic units by 10 and its powers. This feature provided a great convenience to users of the system, by eliminating the need for such calculations as dividing by 16 (to convert ounces to pounds) or by 12 (to convert inches to feet). Similar calculations in the metric system could be performed simply by shifting the decimal point Thus, the metric system is a "base-10" or "decimal" system.

https://standards.nasa.gov/history_metric.pdf

[Karl Andersson]

In addition to Dan's observation that the foot is divided by halves to get its rhythm (and think about it, it's easier for you to eyeball equal half- divisions and come close to the actual increments than it is for you to divide something equally by 10 by eye), the reason that so many other non-metric standards of measure are oddball sizes, weights, and lengths is that the American and Imperial measurements are "modernized" versions of mostly Imperial Roman units of measure. For example, the original mile was 5000 Roman feet/ paces (pes or something like that). A Roman foot measure was a little smaller than what became the British Imperial foot, so when they measured the Roman mile standard, they ended up with less than 5000, but then the King or his Agents decided a mile should be measured in an even number of furlongs, ergo they made the mile a little longer than the original. Gallons, pounds, yards, have all gone through similar conversions, and so, the original rhythms are lost in translation.

On the rare occasions that it comes up, I can impress my European metric-bound wife with my ability to easily rattle off even divisions of something based on halving...but it's hard to convince her that 1/64th is easier to use than, say, .5mm. I stick with the eyeball theory - if I can mark an inch relatively accurately, I can halve that down to at least 1/32 by eye with pretty good accuracy, and I think most people could because of our human wiring. Taking a foot down to inches is a little trickier when you get to the conversion from 3 inches to the individual inch. Technically, we should have 8 or 16 inches to the foot to maintain equal divisions, but 12 probably had some mystical meaning to the Romans, as theirs was 12 inches too.
Karl

[ken hatch]

Some amazing responses, on one side if I can read English (being Texan there is some question on that) are the folks like me that point out that for them it is easier, cuts math errors and is the standard everywhere other than the States. At least for some on the other side you would think the use of whatever you call it, Imperial, Fractional, USSU, or SAE is protected by a sub clause of the Second Amendment, sent men to the moon, plus won WWII. That metric is a plan to steal all our golfs.... besides....France.

ken

[Prashun Patel]

Since getting a Domino and a European jointer/planer, I've been converting more to metric. For me imperial is more visually intuitive, but calculations are more intuitive in metric for me. \

The thing that I haven't seen mentioned as a minor nuissance for metric is using rulers. For imperial, the 1/8" and 1/16" increments are easy to see and precise enough for most of my work, especially when you get comfortable thinking in "1/16 strong, or a smidge less than 1/16". My eye works well and accurately here.

But on a metric ruler, my 45 year old eyes can't see the difference between 22mm and 23mm tick marks. It takes effort to count and recount the little tick marks.

Domino and my Hammer planer rely on digital scales and, preset stops to eliminate that. But it's a new way of working for me. I do like rulers.

[Joel Thomas Runyan]

If we should switch to anything, it's duodecimal, not hex. Base 12 is awesome for basic calculation--ie, the type that comes up in woodworking--because it divides so easily.

A really clear example of the ugliness of bases comes up in time-telling. We have 24 hours in a day, in two twelve hour cycles, but we count them in 10s, so 19:00 is one cycle later than 7:00, which is sort of insane. If we counted in base 12, 17:00 would be one cycle later than 7:00. Which at first glance is also insane, but after a bit of jostling, becomes wonderfully sensible.

I think people tend to question arbitrary things when they're difficult to use, but don't extend their skepticism to all the arbitrary things they've been doing their whole life. If you look at it deeply, most of our systems of measurement and maths are the craziest stew you've ever seen.

[Warren Mickley]

The inch is dived in 16ths (or 32s or 64ths). The feet is divided in 12 inches. The yard in 3 feet. The mile in 1760 yards, which is 110 x 16. The gallon is 57.75 cubic inches.

I have difficulty to find a rythm in these numbers.

Actually we don't use miles or yards in woodworking. I did once see that Lee Valley planed 1.6 miles to test Pmvii (maybe about as much planing as someone like Kees does in a week of spare time). The mile is based on a thousand paces, which is very handy if one wants to know how far he has walked. I will keep the metre in mind the next time I walk from the equator to the north pole. The way we divide the inch is based on actual usage in woodworking. We are constantly dividing measurements in half, not very often diving into tenths.

Likewise we don't use cubic inches when dealing with cider or milk or gasoline. The only ones who have to know these are people who design containers.

My guess is that no one will change to ten hours a day, with centidays, millidays and microdays. Or change to 100 degrees in a circle or a 8.333, 16.667, 25 triangle. or have each time zone have 4.167 degrees of longitude.

For working wood, we don't need to know how many inches it is to the moon.

[ken hatch]

http://i257.photobucket.com/albums/hh222/VTXAZ/guyWalksIntoBar_zps8jshw1oe.jpg

[Pat Barry]

If we should switch to anything, it's duodecimal, not hex. Base 12 is awesome for basic calculation--ie, the type that comes up in woodworking--because it divides so easily.

A really clear example of the ugliness of bases comes up in time-telling. We have 24 hours in a day, in two twelve hour cycles, but we count them in 10s, so 19:00 is one cycle later than 7:00, which is sort of insane. If we counted in base 12, 17:00 would be one cycle later than 7:00. Which at first glance is also insane, but after a bit of jostling, becomes wonderfully sensible.

I think people tend to question arbitrary things when they're difficult to use, but don't extend their skepticism to all the arbitrary things they've been doing their whole life. If you look at it deeply, most of our systems of measurement and maths are the craziest stew you've ever seen.
You might as well be speaking Klingon because none of this makes any sense to me at all. Question - what does a duodecimal or for that matter hexadecimal ruler look like?

[Daniel Rode]

Not Klingon at all. Working in different bases is pretty simple.

Duodecimal would be a system with 12 or 16 equal divisions between "units" rather than the 10 of metric.

So A duodecimal a decimeter would contain 12 centimeters, a meter would contain 12 decimeters. Each centimeter would have 12 millimeters. Clearly unit the naming would need to change :) Hex would be identical but with 16 divisions. 1, 2, 3...9, a, b, etc.

[Warren Mickley]

A duodecimal ruler looks like these two scales from Roubo, B one foot (pied), C Half foot. The foot is divided into 12 inches, the inch is divided into 12 lines. This is the way craftsmen in France worked before the government started telling them what to do.
325568

[Daniel Rode]

The obvious advantage the comes to my mind is that 12 lines makes dividing something into thirds simple. 1/3 of an inch is not so simple nor is a 1/3 of a centimeter.

[Warren Mickley]

Here is a better image of Roubo scales, 12 inches to the foot (pied), 12 lines (lignes) to the inch (pouce)
325574

[Paul Sidener]

Yes I understand that it isn't a problem for you when I write English and use imperial measurements. :D

Well it would be silly for you to use a different language. This forum is based in the Unites States. When in Rome, do as the Romans.

[William Adams]

The obvious advantage the comes to my mind is that 12 lines makes dividing something into thirds simple. 1/3 of an inch is not so simple nor is a 1/3 of a centimeter.

One-third of an inch is two (computer) picas, or one can use a scale ruler: http://www.amazon.com/Staedtler-R-Engineers-Printed-Scale/dp/B00006IAOX

[Nicholas Lawrence]

Some amazing responses, on one side if I can read English (being Texan there is some question on that) are the folks like me that point out that for them it is easier, cuts math errors and is the standard everywhere other than the States. At least for some on the other side you would think the use of whatever you call it, Imperial, Fractional, USSU, or SAE is protected by a sub clause of the Second Amendment, sent men to the moon, plus won WWII. That metric is a plan to steal all our golfs.... besides....France.

ken

My comment about the moon was an attempt at a humourous response to what sounded like a suggestion that the use of inches and feet is a badge of benighted barbarians more at home in the dark ages than the internet age because "science" and "everybody else does it" (I am intentionally exagerrating a little, nobody discussing this has offended me or hurt my feelings, and I hope the reverse is true as well).

Metric does have its advantages in chemistry or some other field where you are dealing with the relationship between volume and mass, and things of that nature, but I don't do a lot of that with woodworking, and I basically think what you do with your ruler matters a lot more than how it is graduated. Like some others who have commented, in woodworking I tend not to measure much. Mostly it is a matter of a rough cut to get fairly close, marking against what I want it to fit, and planing, chiseling, or sawing to the line. 95% of my measuring is for layout or buying material, and it does not matter whether I am counting millimeters, inches, or hand spans.

[jamie shard]

Something close to thirds are probably the most important division for woodworking -- for the basic layout of a mortise and tenons. That's why 12 can be useful. But that's mostly at the scale of timber framing. For most furniture stuff, it's more like a 3/4" board, with 1/4" mortise with 1/4" of wood on either side, or maybe 5/16" with 7/32" of wood on either side is better. I wouldn't go 3/8" mortise with 3/16" of wood on either side, that's too weak on the sides.

I like imperial, it's like the shaku, sun, bu of for us western temple carpenters. :)

[Trevor Goodwin]

Getting a third is awkward in either system. In metric you get a recurring number that isn't marked on rulers, and with imperial it is convenient for a foot (12/3) but for an inch it is isn't marked on rulers either. This got me thinking, maybe there is an imperial ruler that has its inches divided into twelfths...

Found this: http://www.whitechapel-ltd.com/category/bob.html A ruler marked in "twenty-fourths", which is almost the same as one mm. It certainly makes marking of thirds, or sixths of an inch easier.

[Christian Thompson]

Bottom line is that both systems are arbitrary, but the convenience of easier addition and multiplication make metric seem like a much better option to me. That being said, I still use imperial for almost everything since that's what I am used to...

[Kees Heiden]

Just having one standard system is, as far as I am concerned, way more important then any of the arguments posted here. I don't care if it is base 10, 12 or 16. Just choose ONE system, for fricking sake!

;)

[James Pallas]

I'm fairly comfortable using either. I have seen some talk about different rulers. One tool that most of us have is a framing square. On the back side of the square can be found scales in 1/10 and 1/12 and even 1/100. This applies to true framing or rafter squares. Thought this may help someone.
Jim

[Daniel Rode]

The amazing thing about standards is that there are so many to choose from :)

Just having one standard system is, as far as I am concerned, way more important then any of the arguments posted here. I don't care if it is base 10, 12 or 16. Just choose ONE system, for fricking sake!
;)

While the various merits of each system are interesting, things would be simpler if we all used 1 system. I think it's the most complex in the states because we have to constantly deal with 2 different systems and regularly convert between them.

[Jim Koepke]

The amazing thing about standards is that there are so many to choose from :)

Good one Daniel.


While the various merits of each system are interesting, things would be simpler if we all used 1 system. I think it's the most complex in the states because we have to constantly deal with 2 different systems and regularly convert between them.

Actually we have more than that in use. How else could an ounce of gold weigh more than an ounce of feathers while at the same time a pound of feathers weighs more than a pound of gold? (avoirdupois vs troy)

If one does much cooking they are sure to have some recipes that use metric measures, some with volumetric measures and some using weights of the ingredients.


Just having one standard system is, as far as I am concerned, way more important then any of the arguments posted here. I don't care if it is base 10, 12 or 16. Just choose ONE system, for fricking sake!

Most of the world already has by using metric. Here in the states most of us have a system that works for us, yet we tend to be able to get along with what ever comes our way. There is seldom a reason for me to convert one to the other. Most of the time it is when looking for a wrench when it comes in handy to know which of my metric wrenchs will fit an SAE nut or the other way around and that 3/8" or 10mm do not have common equivalents in the other system.

If you want to read about the perils of conversions, search > gimli glider < for a story of conversion error and a strange incident that gave an airplane and a crew their moments of fame.

jtk

[Harry Hagan]

Oh yes, the problem does exist! I face it every time I'm trying to communicate a measurement on this forum. The USA is the last country in the world using imperial. So, as long as you recognise that the world is larger then good old America, then you have to acknowledge that there is a problem.


I beg to differ, Kees. The great countries of Liberia and Myanmar also utilize the Imperial system! :)

[Kees Heiden]

No, not anymore! If I may believe wikipedia.
When I was in Myanmar two summers ago, the road distances were still signposted in miles. I think they might have some other priorities at the moment.

[Keith Outten]

More important to the conversion of the United States to the metric system is the cost. There are hundreds of billions in investment in machines in our machine shops, woodworking shops, etc. We also have an inventory of fasteners that is probably worth more then the total wealth of most countries.

You can't just flick your wrist and command any industry to change to a new system, particularly when the majority of the workforce is accustomed to a system that has been in use for almost 200 years. When the baby boomer generation is gone there may be a chance to make that kind of adjustment but until then it is probably impossible.

Kees, the majority of Americans who actually use a measuring system on a daily basis don't have a problem with the Imperial System. Its simply feet, inches, fractions and decimals which as natural to the older crowd as walking. I wouldn't change it for anything, I refuse to purchase any machine that doesn't support the Imperial System, the rare times that I have to convert is just a nuisance and its probably the same for those in other countries.
.

[Kees Heiden]

That's not a problem, that's an opportunity. Do you know the costs of using a different measuring system? I am not an economics guy, so I really have no idea. I just have the idea that changing over would save a bunch of money. And it wouldn't happen overnight, stock could be used up. Hey, America allready decided in the 1960's to go metric. They should be ready by now.

[Trevor Wentzel]

Living in Canada and being a child of the late 70's mostly a hybrid system is used. I use KM's for distance, but i can use miles just fine in the US.
Weight in pounds, and height in feel/inches...but cm and mm make more sense.... it's whatever you are used to that makes the most sense.
Helping our visiting American friends with Metric time is always a treat... that's 62 min on the hour.

[Jim Koepke]

You can't just flick your wrist and command any industry to change to a new system, particularly when the majority of the workforce is accustomed to a system that has been in use for almost 200 years.

The typical way this can be changed is for all government agencies to rewrite all their purchase orders to require metric components or designations. This would take an act of Congress or possibly an Executive order. An Executive order would only extend to one branch of the federal government.


America allready decided in the 1960's to go metric. They should be ready by now.

The American government and some government agencies decided long before 1960 to use metric. Even in the early days of the United States we didn't have a set system of measurement. Thomas Jefferson did attempt to introduce a measurement system based on the length of a pendulum with a one second arc.

From: https://en.wikipedia.org/wiki/Plan_for_Establishing_Uniformity_in_the_Coinage,_W eights,_and_Measures_of_the_United_States

In coordination with scientists in France, Jefferson selected the seconds pendulum at 45° latitude as the basic reference. For technical reasons, he proposed using a uniform rod as the pendulum rather than a traditional pendulum. The pendulum was estimated to be 39.14912 English inches long (in the inches of that time


I just have the idea that changing over would save a bunch of money.

It would render all my measuring devices obsolete. If all the dowels and other things were only available in metric, then all my drill bits would have to be replaced.

In the long run, the added business activity and conversions might save money at a future time. In the short run it would be inconvenient for many people.

Currently much of our system is changing. The automotive industry uses parts from all over the world and eventually all the parts in an American made car will be in metric designations. Tire designations are almost all now in metric.

What are the biggest problems?

We currently have butter sold by the pound. A nice convenient round number. Does the dairy industry want to start selling half kilos of butter? Would the public feel a little cheated if butter started being sold at a nice round number of 450 grams?

Milk is in quarts, most people might not like the idea of 3.8 liters. Not sure the dairy industry could change all of their equipment to start handling 4 liter bottles.

The beverage industry is split. There are still 12 and 16 ounce bottles, but they also sell liter size designated containers.

The dairy industry changed the packaging on ice cream not long ago. They made the packages a bit smaller. That could have been a good time to go metric.

Just live with the idea that some people are stubborn and when it comes to changing they way they have been doing things all their lives, they may be just a bit more stubborn.

jtk

[Pat Barry]

...the majority of Americans who actually use a measuring system on a daily basis don't have a problem with the Imperial System. Its simply feet, inches, fractions and decimals which as natural ... as walking. I wouldn't change it for anything, I refuse to purchase any machine that doesn't support the Imperial System, the rare times that I have to convert is just a nuisance and its probably the same for those in other countries..
Good on you Keith, now lets call it what it is - the American measuring system. I'm sick of the term Imperial. USA USA USA!

[Nicholas Lawrence]

Hey, America allready decided in the 1960's to go metric. They should be ready by now.

"America" does not equal "the federal government." They are two different things in a way that I suspect is not always intuitive for our friends overseas. Here the federal goverment may "decide" something, but that does not mean it will actually happen if it does not make sense from the point of view of the individual states, local goverments, and private citizens.

Nick

[Pete Staehling]

I use feet and inches most of the time because it is easier with a lot of the tools that I have. Also my customers think in feet and inches, so some key measurements are always given in inches. I was using metric for a while for some operations (mostly laying out fret positions on musical instruments), but for those particular operations I switched to decimal inches.

[Keith Outten]

The American people have never made the decision to convert to the metric system. Our Government established a committe that was supposed to assist the conversion process but their efforts were ignored so the committee was disbanded.

Honestly, in my shop the conversion would put me out of business. All of my machines and my measuring and test equipment are Imperial, replacing everything is an economic impossibility in my lifetime. I expect that most small to medium size companies are in a similar situation and of course you have to consider employees that would resist the change and the ratio of mistakes that would be a burden during the conversion period.

I can't see any cost savings in any scenario that involves converting to the metric system in industrial shops that are already invested in the Imperial system.
.

[Keith Outten]

Good on you Keith, now lets call it what it is - the American measuring system. I'm sick of the term Imperial. USA USA USA!

I agree with Pat, our system is probably better described as the American Measuring System when you consider that we use so many different systems in a variety of industries.
.

[Halgeir Wold]

I love these metric vs imperial debates..:)
You seem to forget that one of the main driving forces behind the french units revolution was to bring forth a unified system, as opposed to the downright jungle of different measures that ruled those days. Even the same unit varied in size between regions and countries, causing trouble and actual fraud.
The basics of this discussion is that we mostly prefer what we are used to. I graduated in electronics in the mid 70s, when computers were really booming, and we counted numbers in decimal, binary, hex and octal, depending on which system you worked on, and conversions were quick, once you got used to it.
Back in the late medievals, the old measurements of thumbs, feets, cubits etc. ruled, but where different from country to country. Norway was a vassal state under Denmark, and in 1615 the official danish-norwegian cubit was standardized by law to 24 danish thumbs, -this thumb has later been defined as 26.17 mm, but still the old norwegian cubit of 55 cm, i.e. 20 thumbs of 27.5mm exists up until today, and both are still being used in traditional boat building, since the length of these boats are defined in cubits, and the rest of the measurements are proportions of the main unit. I deliberately use the old term "thumb", as the inch is a defined size. The old scandinavian term for cubit, is alen ( old norse: alinn), meaning the length of a mans underarm, - elbow to finger tip. ( There are also differet alinns, partly depending on which finger you refer to.. :) ) As you see, standardization has its advantages....
I've spent all my professional life in space related work, and meters, millimeters, inches, feet, miles, knots, meters/second - it just does't matter when you get used to it.
However - I do prefer metric - that's what i grew up with.... ( not quite true,- all our boats were in feet, and construction lumber was in inches....)

[lowell holmes]

One-third of an inch is two (computer) picas, or one can use a scale ruler: http://www.amazon.com/Staedtler-R-Engineers-Printed-Scale/dp/B00006IAOX

I don't think I ever made a cut at 1/3". If I needed to, I would draw parallel lines at 1" and divide that space into 3 units.

You do know that many engineering drawings are drawn with decimals of inches and there are three sided scales divided into 10ths, 20ths, 30ths , ., ., and so on. That is to say drawings are often drawn to 1" = 10', 1" = 20', etc.

Drawings to be used in Europe will often have dimensions expressed in ft and inches as well as metric. I know this to be the case because I've made the drawings.

[jamie shard]

Even the same unit varied in size between regions and countries, causing trouble and actual fraud.

I only heard about this recently and it really does explain why Europe transitioned to metric. Imagine every state in the U.S. with a different sized inch and you could easily imagine everyone saying, "let's forget about who is right and let's all just switch to metric." :)

[Jim Koepke]

I agree with Pat, our system is probably better described as the American Measuring System when you consider that we use so many different systems in a variety of industries.
.

It was my impression it already was the American Measuring System it is just called the American National Standards Institute.

With all the talk about measuring thirds and such it seemed a picture is better than words:

325647

Just as easy with metric or inch denominated rulers.

The metric ruler didn't want to hold still for the picture.

jtk

[Marty Schlosser]

Hey, Shawn,

I don't agree with your premise for dividing metric measurements. We're all used to dividing decimal based numerical systems by 2, 3, 9, or whatever, right, as that's what our number system is based on. By extension therefore, it's very natural for us to easily visualize the resultant fractional figures (13.6mm, for instance).


I grew up with both imperial and Metric. I can use either. I typically use imperial as that is what the tools around here are found. There are pros and cons to both (or maybe it is always a compromise). Neither work well when dividing by 3.

[jamie shard]

The thing about thirds is it isn't so much about measuring it, it's about the next step: chopping out the mortise, putting in the panel groove, etc. Ideally, all of the tools used would be matched, so everything lines up. Obviously any sized mortise and groove can be made, it's just easier if the dimension comes right off the tool. I'm sure there are "classic" metric sizes which serve to approximate thirds in ~2.5 cm stock.

[Allan Speers]

The American people have never made the decision to convert to the metric system. Our Government established a committe that was supposed to assist the conversion process but their efforts were ignored so the committee was disbanded.
.


Remember back in the day (1980's, maybe?) When USA road signs started appearing with both miles and meters? Some food labelling also had both imperial & metric.

This was supposed to help Americans learn metric, by getting us used to some common "benchmark" sizes.


Unfortunately, the idiots behind this project decided to put the imperial measurements FIRST, which meant that no one needed to pay attention to the metric number that followed. Hence, it was a huge waste of time & money, and a complete failure. It's rare that I'll actually knock government employees (privatization of health care & the prison system are both travesties) but in this particular case ......

[Mel Fulks]

Standards did vary but it was also just more dificult to achieve accuracy. But people were careful and frugal,the book on the Stubbs tool company describes a paper memo about a ton of iron that was 5 pounds off. And in modern times ...I once pumped more gasoline into my car than the capacity of the tank, and I didnt push the car to the station. I drove it. Happened in one of the mafia areas. Forgot to mention stubbs memo was early 19th century.

[bridger berdel]

Well, this gets to the strongest argument I know of for the legacy measurements. Metric is great for dealing with things in grand scale like trips to the moon or transglobal commerce, but for things done to a human scale the ability to cleanly divide by many denominators is worth gold.

[Kees Heiden]

Do you really use that ability to divide in equal parts very often? What happens when your board is not 1 foot wide, but 11" 7/64? And you also have to account for the (almost) 1/8" sawkerf width?

I just grab my smarthphone start the calculator and within 5 seconds I know the exact dimensions.

[Reinis Kanders]

I am in the same camp as Kees. Lot of times I just do math in my head, keeps it fresh, otherwise I actually have a reasonably nice calculator that I also use for electronics stuff.
Usually I do not measure much though, just mark it as a go.


Do you really use that ability to divide in equal parts very often? What happens when your board is not 1 foot wide, but 11" 7/64? And you also have to account for the (almost) 1/8" sawkerf width?

I just grab my smarthphone start the calculator and within 5 seconds I know the exact dimensions.

[Daniel Rode]

Not to be contrary, but I would probably not measure directly to split something like 11 7/64 / 2 -1/8 nor would I reach for a calculator. Not for wood working anyway. I would

A) Work towards the measurements on my plan or adjust the plan and very likely end up with 2 5 1/2" pieces.
B) Roughly half the distance leaving the kerf by marking from either side (repeat until if necessary) and then cut between the lines.


Do you really use that ability to divide in equal parts very often? What happens when your board is not 1 foot wide, but 11" 7/64? And you also have to account for the (almost) 1/8" sawkerf width?

I just grab my smarthphone start the calculator and within 5 seconds I know the exact dimensions.

[Jim Koepke]

Not to be contrary, but I would probably not measure directly to split something like 11 7/64 / 2 -1/8 nor would I reach for a calculator. Not for wood working anyway. I would

A) Work towards the measurements on my plan or adjust the plan and very likely end up with 2 5 1/2" pieces.
B) Roughly half the distance leaving the kerf by marking from either side (repeat until if necessary) and then cut between the lines.

I have to agree with Daniel.

The less measuring I do, the better the job seems to go.

It doesn't matter if it is less measuring in metric or in inches, just less measuring while fitting and using methods like dividers and story sticks.

jtk

[Kees Heiden]

I don't do a whole lot of measuring either. Lots of things are marked from each other. After getting the overall dimensions down, the rest follows rather naturally. But I also have an engineering background, so I do like to put a number to it. For example, I need some hinges, a size like this looks good, hmmm how long is that.

I do wonder (genuinely, not pulling anyones legs this time) where the fractions come in. Does someone have examples where this is very usefull? In what situation in woodworking is the ability to easilly divide in halfs, 3rds, 4ths etc, so nice?

[William Adams]

I do a lot of things such as my archery case which have holders for various things. Two necklace posts in a jewelry box will require dividing into thirds — granted, I’ll usually adjust slightly for the sake of proportion from even thirds, but I find it easier to start w/ a nice even measurement (which I’ll grant is oft’ in points).

The 1/25th rule is an interesting compromise, though I’d likely find it more useful @1/24th, w/ further sub-divisions into point — may have to engrave one.

[Steve H Graham]

The decimal inch is proof that metric is superior.

It's the imperial imitation of the metric system.

You don't see the meter imitating the yard.

[Pat Barry]

The decimal inch is proof that metric is superior.

It's the imperial imitation of the metric system.

You don't see the meter imitating the yard.

Steve, this is B_ pure and simple. The metric system has no claim to the decimal system. Decimals were in use long long before the metric system was invented. Engineering drawings have been done in thousandths of an inch in lieu of fractions ever since it has been important to measure and produce things precisely

edit - removed the S to keep folks happy

[Curt Harms]

Steve, this is BS pure and simple. The metric system has no claim to the decimal system. Decimals were in use long long before the metric system was invented. Engineering drawings have been done in thousandths of an inch in lieu of fractions ever since it has been important to measure and produce things precisely

But decimals, whether metric, ANSI, CU(customary units), whatever seem simpler to use in calculations than fractions. Beyond that it's a matter of what we're used to and whether not producing goods using metric specs becomes seen as a handicap to export sales.

[Warren Mickley]

I would like to say that I really appreciate the effort made by Kees and others to post in English using our language and measuring system. An occasional misspelling or odd phrase serves to remind us how well Kees is communicating in English, certainly better than some who speak only English.

Some have suggested that we use feet and inches because that is what we are used to, or that we would certainly prefer the metric system if only we knew it well. I don't think this is quite right. I took fourteen science and engineering courses in college and ten mathematics courses as well. I am very comfortable using the metric system, and have been for fifty years. Many scientists use metric at work and inches for woodworking. We use feet and inches in this system because it lends itself to the work at hand. We would certainly change if it were not so.

[lowell holmes]

Administrators take note

It's time for this string to be put to bed.

[Daniel Rode]

Are you suggesting that we should not be permitted to further discuss measuring systems?

It seems to me that this has been a polite and informative debate. I've learned a lot and I'm still interested in hearing facts and opinions on this subject.

Administrators take note

It's time for this string to be put to bed.

[Hilton Ralphs]

Are you suggesting that we should not be permitted to further discuss measuring systems?

It seems to me that this has been a polite and informative debate. I've learned a lot and I'm still interested in hearing facts and opinions on this subject.

We're obviously not paying enough attention to the sponsors. This thread could go for another 20 pages but I suspect it won't.

[Kees Heiden]

Thanks for the compliments Warren! I use English so much both at work and in the hobby area, that it almost feels like a native tongue. Almost, it never becomes really that easy.

Today I tried the imperial calulating system, but I still found metric a lot easier. That's just to remind that being used to something is a major factor.

[lowell holmes]

Are you suggesting that we should not be permitted to further discuss measuring systems?

It seems to me that this has been a polite and informative debate. I've learned a lot and I'm still interested in hearing facts and opinions on this subject.
Daniel, your right. I'll just quit opening the thread.

[Steve H Graham]

Steve, this is B_ pure and simple. The metric system has no claim to the decimal system. Decimals were in use long long before the metric system was invented. Engineering drawings have been done in thousandths of an inch in lieu of fractions ever since it has been important to measure and produce things precisely

edit - removed the S to keep folks happy


Of course the metric system has a claim. Imperial treats decimalization like a prostitute, good only for isolated flings. Metric is married to it.

You can use decimal inches, sure. But you don't. Not most of the time. Most of the time, you're forced to use fractions. If you to go an American lumberyard, you can't have a 50mm x 100mm. You have to ask for a 2 x 4, which isn't even 2" by 4"! Your wrenches are fractional. Your measuring tapes are fractional. Your power tools are set up for fractions. If everything was metric, you would never have to worry about common denominators or adding fractions. The fact that you own a decimal-inch dial caliper doesn't begin to make up for that.

How many gallons are in a hogshead? How many furlongs are in a mile? How many roods are there in an imperial light year? Danged if I know. Neither do you. With the metric system, you just add or remove things that look like " x 10^n", or you change the value of "n," and you're all done. You don't have to worry about bizarre, ten-digit quotients. You don't even need to know the names of the units. In metric, the speed of light is commonly measured in meters or centimeters per second, not the ridiculous "miles per second" of the imperial system. To switch, you just change the exponent. That's the way metric works. Metric is MADE for scientific notation, which is one of the neatest tools science and engineering have.

Imperial is a horror. When I was getting my physics degree, we always used metric. I found out why when I looked at old imperial physics! What a joke. Slugs! Grains! Crazy measurements no one could get a feel for without years of practice. And the conversions...crazy!

To this day, I can only picture a few non-metric measures in my head. I can imagine a foot or a mile, but don't ask me to pour you a dram without looking at a reference book.

I remember my E&M prof in grad school, talking about the suffering involved in using fractional materials to build waveguides. No one should be put through something like that.

Decimalization, whether it came before or after the metric system, shows that powers of ten are the way to go. Metric never had any wacky non-decimalized units to begin with. Imperial is still packed with them.

Hatred of nutty imperial and non-decimal measurements is the main motivation for the development of the metric system. I looked it up. An academic named Wilkins tried to create and promote a decimalized measuring system with a standardized inch, starting in 1668. Obviously, he failed, and Thomas Jefferson, along with other frustrated scholars and engineers, took up the cause a hundred years later. Jefferson is apparently the reason we have ten dimes to a dollar, instead of 53 shillings or whatever.

If the decimal inch existed prior to the 1790 creation of the metric system, it certainly failed as a replacement. There is more to life than length. And even today, the decimal inch doesn't solve the problems of feet, yards and miles, which are stupid and inconvenient in calculations.

[jamie shard]

You have to ask for a 2 x 4, which isn't even 2" by 4"!

That could be another nine page thread. :)

[Jim Koepke]

Steve,

As spot on as your post may be, very few people today measure in hog's heads or ask for a dram of your finest whiskey.

Many folks may not be able to tell you a shot of liquor is one once, but they often will consume a shot.

My science classes taught us light travels at approximately 186,000 miles a second. If it is wanted in meters per second, ask Dr. Google.

Rods, chains and many other measuring designations are mostly for specific disciplines and I do not know if they are still in use. My recollection of a chain measurement was while packing shipments. We had a 108" chain to check packages. At the time UPS was not allowed to take a package exceeding 108" total of length + width + girth.

I doubt if many folks work with grains unless they are working with pharmaceuticals or packing powder into bullets.

For many it is easier to say an inch and five eighths or one and five eighths inches than it is to say one point six two five inches. Most Americans would give a strange look to the one saying the latter. Likewise, most Americans wouldn't have a clue if you said forty one point four millimeters.

We would need a great exchange to make the switch. Take an old ruler to the nearest big box store to get it exchanged for a new metric ruler or two. There would still be those who wouldn't let go of their old rulers.

If it isn't going to put two cars in the garage along with a few weeks food in the freezer most Americans will remain happy with what they have.

Now here is a real conundrum of which my knowledge is zilch. The NATO round at 5.56mm is interchangeable, in some cases, with the American Sporting .223 round. The most important difference is in the chamber. The NATO round tends to have a bit more room between the bullet and the rifling to allow for the heavier amount of explosive used in the military round. At least that is what is floating around the internet.

Think I'll go pour myself a pint.

jtk

[Jim Koepke]

Looks like things are being worked on, the edit function isn't working as yet.

I forgot to ask after the sentence about 1-5/8", how does one go about measuring parts of a millimeter when it is greater than the opening on a caliper?

[Tom Stenzel]

"America" does not equal "the federal government." They are two different things in a way that I suspect is not always intuitive for our friends overseas. Here the federal goverment may "decide" something, but that does not mean it will actually happen if it does not make sense from the point of view of the individual states, local goverments, and private citizens.

Nick

When Dennis Archer was mayor of Detroit, he send out a directive that stated all future City of Detroit contracts, drawings, specifications were to be done using the metric system.

It was ignored. Completely. When I left anything that came metric was by chance. By the way, the directive was, of course, printed on 8.5" x 11" paper.

I looked for my copy of it years later but must have deep-sixed it. Yet another historical curio.

-Tom

[Steve H Graham]

If I start talking about firearm calibers, there is a good chance my head will actually fly off.

Why is it that .308 = .30 = 7.62mm NATO, but a 7.62mm Eastern bloc cartridge is .310? Why do we call the shorter, weaker 10mm ".40 S&W" instead of something like "10mm Puny"? Why is a super-powerful .38 a .357 Magnum instead of a .38 Magnum? Why is a .45 auto actually a .451?

Who are the crazies who inflicted this stuff on us?

[Jim Koepke]

This was supposed to help Americans learn metric, by getting us used to some common "benchmark" sizes.

I think most people are comfortable with what the know.

American's will not likely change unless they are given no alternative.

It would not surprise me if the electronic scales used at checkout in most markets could be changed to metric in minutes. The scales for use in the produce departments would likely need to be changed out. At least the face plates.

Like so many things it will be a long and drawn out road to change.

Some industries have changed. All my medicines including over the counter items are designated in metric.

An interesting read is the story of the British change to metric:

https://en.wikipedia.org/wiki/Metrication_in_the_United_Kingdom#Wholesale.2C_ret ail_and_consumer_industries

It only happened after it was mandated.

Seems many of their gas pumps could be switched between metric or Imperial measure. The unit price couldn't go above £1.99. When fuel prices started to climb, instead of getting new pumps the life of the existing pumps was extend by switching to selling fuel in liters.

Also from the same page is the idea of carpet or fabric sold by the square yard. The price looks better than the same unit price when sold by the square meter.

jtk

[William Adams]

38 Special is not 0.38" caliber, it’s named for the 3/8" tool which was used to ream out the chambers when converting percussion revolvers to cartridges.

[Curt Harms]

If I start talking about firearm calibers, there is a good chance my head will actually fly off.

Why is it that .308 = .30 = 7.62mm NATO, but a 7.62mm Eastern bloc cartridge is .310? Why do we call the shorter, weaker 10mm ".40 S&W" instead of something like "10mm Puny"? Why is a super-powerful .38 a .357 Magnum instead of a .38 Magnum? Why is a .45 auto actually a .451?

Who are the crazies who inflicted this stuff on us?

Re the .308 vs. Eastern Bloc .310, I've read that was done so Eastern Bloc weapons could fire captured NATO rounds (little undersized but they worked) but NATO weapons couldn't chamber the oversized Eastern Bloc rounds.

[Rich Riddle]

I began using metric after purchasing a Hammer K3 Winner. It works much simpler than imperial. An old-timer named Steve Mickley taught me that measuring is the enemy of accuracy and taught how to use a story stick. I might be the only one who uses one of those though.

[Hilton Ralphs]

An old-timer named Steve Mickley taught me that measuring is the enemy of accuracy and taught how to use a story stick. I might be the only one who uses one of those though.

I doubt that very much. Plenty posters on this forum use story sticks, be it the bought version or the home made version.

[Jim Koepke]

I doubt that very much. Plenty posters on this forum use story sticks, be it the bought version or the home made version.

Mine was even posted here:

http://www.sawmillcreek.org/showthread.php?226134-Story-Stick-Gauge

Don't have to figure inch or metric with a story stick.

jtk

[Pat Barry]

Mine was even posted here:

http://www.sawmillcreek.org/showthread.php?226134-Story-Stick-Gauge

Don't have to figure inch or metric with a story stick.
.
jtk
Well, you do have to start with something. You need to measure the initial dimensions. Can't just randomly pick something. Even that starts with measure and mark your stick. I'm betting you use American dimensions Jim :)

[Jim Koepke]

Well, you do have to start with something. You need to measure the initial dimensions. Can't just randomly pick something. Even that starts with measure and mark your stick. I'm betting you use American dimensions Jim :)

Actually on this one it started with a length of wood and my golden ratio calculator. That was made with metric dimensions but works in any system.

Some of the dimensions were based on the size of boxes for my wife's tea.

But if there was any measurements they were likely made with a Stanley four fold ruler, which is in inches.

jtk

[James Pallas]

For myself I just use measuring devises to transfer a known demension to material to work on. I can use anything to do this imperial, metric, a stick, just anything handy. I have built many pieces not taking a measurement at all. Sometimes I just work with what I have. I see a piece of wood and think it would make a nice small table top and go from there. I find pieces that will work for legs and some that will work for aprons and bulld it up by eye. Match the legs up match the aprons up and build it. In most cases unless you are working from drawings or have to have a fixed size your eyes and matching like pieces is just fine.
Jim

[lowell holmes]

The decimal inch is proof that metric is superior.

It's the imperial imitation of the metric system.

You don't see the meter imitating the yard.
In your shop - yes.
In my shop-NO

[Pete Staehling]

The decimal inch is proof that metric is superior.

It's the imperial imitation of the metric system.

You don't see the meter imitating the yard.

Since the imperial system predates the metric system by a very long time, I doubt that it is imitating the metric system. I would agree that without external factors like customer preferences, the system used on readily available tools, or a life long familiarity with one or the other; the metric system is superior. The thing is that we don't live in a world without those factors, so for many of us the Imperial system makes more sense. I kind do wish that the US had successfully made the switch back in 1975 or so when they were making efforts in that direction.

[Steve Peterson]

I use Imperial, but convert everything to the closest thousandth of an inch. Most of my tape measures are Imperial. I usually buy rulers with a scale for 10ths, 100ths on one side and 1/16ths, 1/64ths on the other side. Imperial calipers read in thousandths.

So in effect, I am using Imperial in a metric fashion. I would have preferred to make the switch to metric in the 70s.

Steve

[Jim Koepke]

I would have preferred to make the switch to metric in the 70s.

As one who is getting closer to his 70s, I am not looking forward to it one iota.

jtk

[ken hatch]

As one who is getting closer to his 70s, I am not looking forward to it one iota.

jtk

Come on Jim, I'm older than you are and made the change.....man up :D.

All kidding aside, not converting to metric is costing the States and by extension all of us money. It is the smart thing to do and the longer we wait the more it will cost. For all the "I'll convert when they pry my yard stick from my cold dead hands" folks, no one is coming for your fractional measuring tools and after the States converts to metric you will be able to work in fractions until you croak and have a great view of the grass from the roots. But in time everyone will be better off once we convert.

ken

[Frederick Skelly]

I kind do wish that the US had successfully made the switch back in 1975 or so when they were making efforts in that direction.

Me too Pete. But I was taught both systems from an early age. I sure understand why some Creekers oppose it. If the US converted next year, I don't know that I'd ever convert my shop. I'd have to look at the impacts a bit more - it might be just a matter of swapping the tapes on my machines and buying new rules. Never really looked into it.

Edit: Heck, if it's that easy I might go ahead and convert now to get the benefits of metric. ☺

[Jim Koepke]

But in time everyone will be better off once we convert.

I am sure you are right.

It will likely be a generational thing. It will have to be mandated in schools and other areas.

I think the reason we haven't changed is most people have never felt a need to change.

Hopefully soon, we will have a whole generation who can work well with both systems. Then it will be easy to have the next generation with metric and a little understanding of the old systems. Then we will move to all of our yardsticks and other measuring devices being relegated to antique stores.

One thing for which there is never a shortage is inertia.

jtk

[Pat Barry]

Come on Jim, I'm older than you are and made the change.....man up :D.

All kidding aside, not converting to metric is costing the States and by extension all of us money. It is the smart thing to do and the longer we wait the more it will cost. For all the "I'll convert when they pry my yard stick from my cold dead hands" folks, no one is coming for your fractional measuring tools and after the States converts to metric you will be able to work in fractions until you croak and have a great view of the grass from the roots. But in time everyone will be better off once we convert.

ken
This is exactly what THEY WANT YOU TO BELIEVE, when, in fact, if it were truly the case, the conversion would have happened years ago. In fact it has happened where its beneficial. Lets take cooking and baking - where exactly would the benefit be to making that switch? Only for the companies making metric spatulas and bowls and strainers - its laughable. I've heard this go metric bs since the 70's. No one can show any benefit whatsoever. DO you think its affecting trade? Not in the slightest. If companies want to sell their spatulas in Europe then they'll make em metric.

[Andrey Kharitonkin]

Me too Pete. But I was taught both systems from an early age. I sure understand why some Creekers oppose it. If the US converted next year, I don't know that I'd ever convert my shop. I'd have to look at the impacts a bit more - it might be just a matter of swapping the tapes on my machines and buying new rules. Never really looked into it.

Edit: Heck, if it's that easy I might go ahead and convert now to get the benefits of metric. ☺
Well, besides rulers and tapes... there are bolts and nuts and tools for that. Router lifts have inch threads that advance the thing and other similar machines where number of revolutions governs travel distance. I mean if you have incra fence and want to switch to metric you have to buy conversion kit to replace those threads and nuts. That would cost a lot for sure...

The rest is purely brain excercise which is good thing as any other excercise, as to know more than one language. Important for when we get older.

[Curt Harms]

This is exactly what THEY WANT YOU TO BELIEVE, when, in fact, if it were truly the case, the conversion would have happened years ago. In fact it has happened where its beneficial. Lets take cooking and baking - where exactly would the benefit be to making that switch? Only for the companies making metric spatulas and bowls and strainers - its laughable. I've heard this go metric bs since the 70's. No one can show any benefit whatsoever. DO you think its affecting trade? Not in the slightest. If companies want to sell their spatulas in Europe or anywhere else in the world except Liberia or Myanmar (we keep such esteemed company:)) then they'll make em metric.

I wonder what it would cost manufacturers to produce two product lines, identical except for graduations. Probably not much, measuring cups have come with dual scales for years and it's trivial to produce digital readouts with different units. If a machine manufacturer had to produce two lines of machines identical except for holes, threads and fasteners that seems like it'd be pretty inefficient. Or kiss off the export market I guess.

[Jim Koepke]

If a machine manufacturer had to produce two lines of machines identical except for holes, threads and fasteners that seems like it'd be pretty inefficient.

If you have worked on automobiles you would notice that a lot of American vehicles have a lot of metric sizes already. Often they are in sizes that are close/equivalent to metric sizes so SAE tools can be used.

Fortunately for me when my 1994 Dodge truck needed work away from home, I brought some of my metric tools along. One bolt was a 15mm which doesn't translate into common inch sizes.

Many years ago a mechanic friend told me it was less expensive to set up a shop with metric tools since there are less SAE sizes needed to fill in the gaps than if you set up with SAE tooling and then filled the gaps for the metric.

Though my wood shop is set up pretty much in inch, my automotive tools are pretty much metric.

I have not converted to metric, but I am not stuck on inches. Inches work for most of what I do so why not go with it. There is no advantage for me at this point to change.

This subject always reminds me of a conversation with a former co-worker. I had misplaced a socket of mine. It was 19mm socket brought from home. When I asked him if he had seen a stray 19mm socket, he asked why in heck I would have a metric socket at work. I explained it is the same size as 3/4". He then wondered why I didn't just ask him if he had seen a 3/4" socket. I explained it was marked 19mm on the socket. Again he asked why I would bring a metric socket into an SAE shop. He is/was one of those brain shy folks who can turn anything into an argument. I tended to avoid him after a while.

Here is a list of wrench sizes in metric and SAE:


Metric to SAE wrench sizes. 6.5mm is common in many wrench sets. A 't' next to the wrench size indicates this wrench will be tight on its equivilent size nut, i.e. a 14mm wrench is snug on a 9/16 nut.

Millimeters - Inch
6 - N/A
6.5 - 1/4t
7 - N/A
8 - 5/16
9 - 11/32t
10 - N/A
11t - 7/16
12 - N/A
13 - 1/2t
14t - 9/16
15 - 19/32 (not common)
16 - 5/8
17 - N/A
18 - N/A
19 - 3/4 (This is such a perfect match, it is used internationally for automobile wheel nuts)
20 - N/A
21 - N/A
22t - 7/8

32 1-1/4 If memory serves me well, this is the size of the hub nut on the rear axle of Volks Wagons before '68 or so.

That has 7 metric sizes throughout the range not covered by an SAE wrench set.
3/16 would be tight on a 5mm, neither size is included with most sets.
Three common SAE sizes, 3/8, 11/16 and 15/16 are not covered by the metric sizes.


jtk

[Frederick Skelly]

If you have worked on automobiles you would notice that a lot of American vehicles have a lot of metric sizes already. Often they are in sizes that are close/equivalent to metric sizes so SAE tools can be used.

Fortunately for me when my 1994 Dodge truck needed work away from home, I brought some of my metric tools along. One bolt was a 15mm which doesn't translate into common inch sizes.

Many years ago a mechanic friend told me it was less expensive to set up a shop with metric tools since there are less SAE sizes needed to fill in the gaps than if you set up with SAE tooling and then filled the gaps for the metric.

Though my wood shop is set up pretty much in inch, my automotive tools are pretty much metric.

I have not converted to metric, but I am not stuck on inches. Inches work for most of what I do so why not go with it. There is no advantage for me at this point to change.

This subject always reminds me of a conversation with a former co-worker. I had misplaced a socket of mine. It was 19mm socket brought from home. When I asked him if he had seen a stray 19mm socket, he asked why in heck I would have a metric socket at work. I explained it is the same size as 3/4". He then wondered why I didn't just ask him if he had seen a 3/4" socket. I explained it was marked 19mm on the socket. Again he asked why I would bring a metric socket into an SAE shop. He is/was one of those brain shy folks who can turn anything into an argument. I tended to avoid him after a while.

Here is a list of wrench sizes in metric and SAE:


Metric to SAE wrench sizes. 6.5mm is common in many wrench sets. A 't' next to the wrench size indicates this wrench will be tight on its equivilent size nut, i.e. a 14mm wrench is snug on a 9/16 nut.

Millimeters - Inch
6 - N/A
6.5 - 1/4t
7 - N/A
8 - 5/16
9 - 11/32t
10 - N/A
11t - 7/16
12 - N/A
13 - 1/2t
14t - 9/16
15 - 19/32 (not common)
16 - 5/8
17 - N/A
18 - N/A
19 - 3/4 (This is such a perfect match, it is used internationally for automobile wheel nuts)
20 - N/A
21 - N/A
22t - 7/8

32 1-1/4 If memory serves me well, this is the size of the hub nut on the rear axle of Volks Wagons before '68 or so.

That has 7 metric sizes throughout the range not covered by an SAE wrench set.
3/16 would be tight on a 5mm, neither size is included with most sets.
Three common SAE sizes, 3/8, 11/16 and 15/16 are not covered by the metric sizes.


jtk

Jim, I never thought of this approach, but I like it! Thanks for the idea.
Fred

[lowell holmes]

Me too Pete. But I was taught both systems from an early age. I sure understand why some Creekers oppose it. If the US converted next year, I don't know that I'd ever convert my shop. I'd have to look at the impacts a bit more - it might be just a matter of swapping the tapes on my machines and buying new rules. Never really looked into it.

Edit: Heck, if it's that easy I might go ahead and convert now to get the benefits of metric. ☺

I don't oppose it. I'm just not going to convert my shop. I have made many drawings showing metric dimensions and also drawings that show both imperial and metric dimensions. There's nothing particularly difficult with metric if it suits you.

I have a 16 bit set of Irwin auger bits in a wooden case that were my fathers. I have a Stanley Bell brace. I use these all the time. Now what would I do with them if I converted to Metric.

I also happen to like and use 6 foot folding carpenters rules. And, when I break one of the 6 foot rules, I end up with a folding yard stick which I like to use. Lets see, also framing sqares have a place in my shop. I like them, why would I give them up. And there are other things. I'm happy with my shop and I'm not changing it.:) If you go to one of the big orange box stores, the lumber is not sold with metric dimensions. My thickness planer is imperial in the thickness settings. And so on. . . . . . . . . .

[Brian Holcombe]

This thread in interesting in that it's had some staying power.

I just use whatever is convient. Matching is important, for instance I have a 6mm mortise chisel that actually measures .250" and so I use it in conjunction with my .250" grooving plane.

[Steve Voigt]

I use Imperial, but convert everything to the closest thousandth of an inch. Most of my tape measures are Imperial. I usually buy rulers with a scale for 10ths, 100ths on one side and 1/16ths, 1/64ths on the other side. Imperial calipers read in thousandths.

So in effect, I am using Imperial in a metric fashion. I would have preferred to make the switch to metric in the 70s.

Steve
I do the exact same thing. I bet you are a machinist. I used to be one, and thousandths are permanently imprinted on my brain. Intellectually I can certainly agree that the metric system has advantages, but I think in Imperial and that's not going to change.

[Steve Voigt]

Jim K. and Brian raise a good point, which is that there are benefits to being conversant in both systems, even if you prefer one. I just bought some 5 mm end mills today because they were the closest thing to the ideal size, and the price was better than 3/16ths. And like Jim, I've used metric sockets forever, because my first 2 cars (and first 4 engines :p) were Volkwagens. I never had to buy a whole set of SAE sockets--just filled in the missing gaps in my metric set.

[Derek Cohen]

Jim K. and Brian raise a good point, which is that there are benefits to being conversant in both systems, even if you prefer one. I just bought some 5 mm end mills today because they were the closest thing to the ideal size, and the price was better than 3/16ths. And like Jim, I've used metric sockets forever, because my first 2 cars (and first 4 engines :p) were Volkwagens. I never had to buy a whole set of SAE sockets--just filled in the missing gaps in my metric set.

I mentioned early in this thread that I use both systems, often at the same time. Sometimes it is forced upon me - my Hammer jointer/thickernesser-planer uses metric, and all the screws/bolts available are imperial (this is in metric country).

I would not replace 5mm with 3/16" since 3/16" is 4.75mm. I have been making drawer slips and grooving with a plough with a 3/16" iron. This has to run into the front groove (behind the drawer front). The drawer front is bowed and I cannot use the plough plane. If I use a router, it needs a 3/16" and not a 5mm bit otherwise the grooves will not match.

I have restored cars for many years and the socket set I have is interchangeable between metric and imperial.

Regards from Perth

Derek

[Steve Voigt]

I would not replace 5mm with 3/16" since 3/16" is 4.75mm. I have been making drawer slips and grooving with a plough with a 3/16" iron. This has to run into the front groove (behind the drawer front). The drawer front is bowed and I cannot use the plough plane. If I use a router, it needs a 3/16" and not a 5mm bit otherwise the grooves will not match.



It obviously depends on what you're doing…if you're just roughing out a slot that will be pared with a chisel, one's as good as the other.

[lowell holmes]

This thread in interesting in that it's had some staying power.

I just use whatever is convient. Matching is important, for instance I have a 6mm mortise chisel that actually measures .250" and so I use it in conjunction with my .250" grooving plane.

My first set of good chisels was a four chisel Marples Blue Chips from Lowes. I learned to match the metric chisels to the nearest imperial widths. I tired of that and started buying antique Stanley chisels. I started getting some good chisels and some inferior chisels as far as metallurgy was concerned.

That's when I bought some Lie Nielsen chisels. They are good in every way, fit,finish, accuracy, and sharpness.

[Brian Holcombe]

At the risk of being pulled into this thread :D It has not been an issue for me, in Cases such as through tenons I appreciate the room, it allows me to pare the sides.

So there are benefits to both sides of things, but in the places where I need a match, I have them predetermined. In the case mentioned with the '6mm' mortise chisel, it arrived at something like .260" and I ground it down to .250".