mm vs inches

[Michael Handrinos]

Hi all.

I'm looking at getting a couple of new rulers and wondered how many of you have made the switch and how you felt about it. Glad you did or wished you used the money elsewhere and stuck to inches

Thanks

[Cary Falk]

To me it doesn't really matter. It's all relative. Whether something is 200mm or 7.8" it is the same length. I use inches because that is what I like to use and I am more confortable with. My blades and bits are in fractions already. The math is easier with metric for people that can't do fractions. I do use metric(mm, microns, angstroms, mL, etc) at work. It's like watching the weather channel. They say it is 20 degrees Celsius outside and I don't know if I should wear a coat or shorts. I don't want to do the math to figure it out.

[Rod Sheridan]

Hi, I switched to metric when I decided to build some cabinets using the 32mm system.

All of my education through post secondary has been in metric, and of course Canada switched in the seventies.

Now when I design furniture I make pieces 20mm thick instead of 3/4" thick, 50mm instead of 2" etc.

When I purchased my new planer I ordered it with the digital height gauge in mm, so all I do is set it at 20.0mm and insert the wood.

A mm is a great size of unit for wood working as it's aproximately 1/25 of an inch.

Measuring devices are normally in 1mm graduations, which is easy to see, and easy to split if you need 1/2 of 1 mm which is about 1/50 of an inch.

Most tape measures are dual reading which helps with the adjustment process, for example if you want a desk surface 30 inches above the ground you can look on the tape and read 762mm so round to 760mm which helps with everything else.

My saw has a dual reading tape for rip and crosscut, it's far easier to set the fence or flip stop to 542mm than 21 11/32

It is far easier to design your furniture in metric as there aren't any fractions. This isn't meant to indicate that I'm not competent to work in fractions, most of my job is mathematics. It's simply easier and less prone to error to add whole numbers.

Of course if you use the 32mm system, it's all metric.

I suggest you try it out, don't try to convert back and forth, that's a disaster.

Measure a few items you use as design elements and convert them to metric (desk height, apron width, leg thickness etc), and round them to nice usable metric values. Write those down and keep them, soon you'll be thinking in terms of an apron width of 80mm, a leg thickness of 60mm etc, and you'll develop some familiarity with the system.

After all, you learned the Imperial system, you had to learn that legs that are 2 to 3 inches square are in the normal range of sizes for certain furniture styles.

Make a drawing in metric and use it to build something simple, you'll be amazed at how much you like it.

regards, Rod.

[John Coloccia]

I'll make the switch completely to metric one day, but a nice compromise for now is to dump all the fractions as use decimal points. Heck, you can use Miliinches if you want to. Just because everyone says 1 1/4" doesn't mean you can't think of it as 1.25". Thats what I do at the moment, and I get the best of both worlds: a) I don't have to convert everything over to Metric, including all of my tools, tapes etc, and b) I don't have to deal with fractions.

Sometimes fractions are convenient, but it's far simpler for me to work with decimal points most of the time, Metric or otherwise.

So you may want to pick up a ruler graded in 50ths on one side and 100ths on the other. 10th would be nice too but that's easy enough to do with 50ths.

[Fred Belknap]

Worked heavy construction most of my life and the plans were drawn in tenths of a foot. It takes some getting use to.

Fred

[Chip Lindley]

I'll make the switch completely to metric one day, but a nice compromise for now is to dump all the fractions as use decimal points.

Stanley does make a "decimal" tape measure! Using thousandths of an inch rather than coarse fractions (1/64" = .015625") allows for finer woodworking when the occasion arises. IMO, decimal measurements are more useful for machine setup and fasteners than for casework or lumber measurements. Were we to go totally digital, we still have to convert 15/32" plywood back to "thousandths"!


They say it is 20 degrees Celsius outside and I don't know if I should wear a coat or shorts. I don't want to do the math to figure it out.

Exactly! It is said you never master a foreign language until you "think" in that language. Converting mentally from one language to the other does not count. I can spread my fingers and show you 3 inches BUT I cannot show you how long 300mm is! Many of us will always "think" in inches, feet, pounds, miles, and degrees F. My grandchildren may be taught to "think" metric, but I never will!

Of course, I can convert inches to mm. when necesssary, and vice versa. I must do it every day! All imported machinery uses metric nuts and bolts. But, most every other aspect of woodworking in the U.S. is in inches/feet. The building trades still use lots of inches and feet. A wall stud is 8 ft. long. A sheet of plywood or MDF is 4x8 ft. 12-2 wire comes in a 250 ft. roll! etc, etc.

A cubic meter of concrete? How many kilometers per liter does your new truck get? Until every quantity and size is offered ONLY in metric measurement, the two systems Will be obliged to coexist. Our infrastructure in the U.S. is firmly entrenched in the inch/pound system, in more ways than we can imagine.

[Rod Sheridan]

Chip, that's true, however Canada used the Imperial system until the seventies and then we switched. It's not that difficult.

As you indicated you're familiar with 70F, not 20C. I was also until I stopped using the Fahrenheit scale, and Chip, I have faith that you're clever enough to learn a new system, your posts demonstrate that.

Regards, Rod.

[Rod Sheridan]

Interesting Fred, a metric foot:D

regards, rod.

[Chris Padilla]

I have two metric left feet according to my European wife. :D

For my wife's sake, I've learned Celsius. It breaks down rather easily:

0 freezing
10 cold
20 warm
30 hot
40 really hot

Now you know. :)

[Brian Tymchak]

I bought rules with both cause I'm not about to convert completely over. Just need to handle the times where going metric makes life easier. For instance, last year, in using "real" baltic birch ply for some cases, I thought it was easier to layout dados using mm scales as the thickness of the panels is manufactured in mm. The inch measurements that BB is sold by in the US are approximations.

Grabbed this (without permission) from the Allied Veneer Company website:
---
Q: What thicknesses do you carry?
Thickness and unit quantities are defined as the following:
Thickness (mm) *Thickness (inches) Sheets per unit
3mm (1/8")- 130 sheets6mm(1/4")- 65 sheets9mm (3/8") - 44 sheets12mm (1/2") - 33 sheets15mm (5/8") - 26 sheets18mm (3/4") - 22 sheets
* Note - the Baltic Birch thicknesses in inches are approximate. For example, the most common thickness for drawer sides is 12mm or ½". However, a true half inch = 12.7mm. Baltic birch has been around long enough that the equivalency ratios stated above are considered the norm.
--------

[Rod Sheridan]

I have two metric left feet according to my European wife. :D

For my wife's sake, I've learned Celsius. It breaks down rather easily:

0 freezing
10 cold
20 warm
30 hot
40 really hot

Now you know. :)

Gee Chris can we tell you're from a warm area 10 degrees is cold??????

here's how it works for Canadians

-40 Intersection of F and C scales, good ice fishing hut weather

-30 Time to wear long underwear

-20 Nice winter carnival weather

-10 Time to zip up jacket

0 can't use the porch as a freezer any more, plaid shirt weather, no more jackets

5 motorcyle weather again

10 t shirt weather

20 Warm weather

30 uncomfortably hot weather

40 why would anyone live where it gets to 40?

regards, Rod.

[Jim McFarland]

I prefer metric for shorter lengths in particular. I use 150mm double square & 300 mm combo square and sold my 6" & 12" blades. Also easier to calculate & mark equal segments using metric IME. I'll confess I still use a 25' tape for rough-in type construction measurements though :o (easier for me to estimate 10' than 3,048 mm!).

[Paul Symchych]

I use both, depending on how critical it is. Starting with some harpsichords I built a while back I have since found that mm. was simpler than trying to add and subtract fractionals accurately and quickly. But, cutting a 2x4 to length... thats more intuitive for me in Imperial where being off by a millimeter isn't a disaster. So I think in feet and inches for the most part but often use metric for really accurate work
It isn't easy to get good rules or tapes with both metric and Imperial on them though.

[Will Overton]

I think in time we all must go to metric. So, not to be hypocritical, I have decided to be buried in a metric sized coffin. ;)

[Chen-Tin Tsai]

As I am primarily a hand tool woodworker, I think in inches/feet. I can approximate an inch (width of a thumb) or a foot (length of my foot) and divide in half and half again. I think for something like wood, that's a natural, (once) living product, it's very well suited. Since furniture is built to be used by humans, which can easily be measured in inches and feet, it seem natural to me to measure it in inches and feet.

[Jamie Buxton]

Stanley does make a "decimal" tape measure! Using thousandths of an inch ...

Do you have a part number on that? The only Stanley decimal tape I could find was an "engineering" tape which had decimal feet.

[Neal Clayton]

i would switch since i like digital measuring tools, but with tooling still in standard measurements it isn't that simple.

for example a tenon inside of a cope/stick joint is the difference between the copes and the total thickness. if the cope depth is standard, the tenon will wind up standard. you can't cope 15 millimeters on either side of a 1 3/8" board and then use a 3/8" mortise chisel and have the tenon fit, it doesn't add up.

for that reason i don't think it likely that there will ever be a complete switch. people have been using cutters with standard measurements for architectural details forever.

[Chris Parks]

It is not a short term thing for a country to convert, in fact it most probably takes a complete generation to do. Australia, New Zealand, Canada and a few others are still in the process many years down the track. I converted totally when I built a new workshop and never went back and don't want to.

[Curt Harms]

here's how it works for Canadians

-40 Intersection of F and C scales, good ice fishing hut weather

-30 Time to wear long underwear

-20 Nice winter carnival weather

-10 Time to zip up jacket

0 can't use the porch as a freezer any more, plaid shirt weather, no more jackets

5 motorcyle weather again

10 t shirt weather

20 Warm weather

30 uncomfortably hot weather

40 why would anyone live where it gets to 40?

regards, Rod.

Why would anyone live where it gets to -40.....on either scale :eek::eek: Though I agree with you, 35* is plenty warm especially if dewpoints are in the mid '20s

:)

I lived in Minnesota for a short time in the early '80s. I recall one stretch with nice even -100* F wind chill. I didn't shut a tractor off 'cause i figured I'd never get it started again. I miss that not at all.

[mickey cassiba]

Worked heavy construction most of my life and the plans were drawn in tenths of a foot. It takes some getting use to.

Fred
I surveyed for a few years...decimal feet are a little weird 'til you get used to them

[Josiah Bartlett]

Most of the time I don't measure at all and use a story stick, but when I do measure I typically use inches and decimal inches, not fractions. I use a machinist's scale for measurement.

[Leo Graywacz]

Hey Joe...Could you cut me a board 37 3/8 centimeters please... :D

[Gil Knowles]

I live in Canada and we switched to metric in the 70's. However when I was in school it was still the imperial system. I have switched to metric for a couple of things but as far as woodworking goes it is still feet and inches. Years ago I bought a couple of tapes which were both metric and imperial and I hated them. When I was in the States on a vacation I picked up a tape at Sears that was just in inches. I still have and use it today.

Gil

[Whit AndersonIL]

A lot of my tools are Inches (table saw scale, router bits, chisels, etc.). For that reason alone, I mostly use inches.

--Whit

[Chris Parks]

Hey Joe...Could you cut me a board 37 3/8 centimeters please... :D

In Australia everything in woodworking/building construction is measured in millimeters/metres with centimetres never being used used.

[Rich Engelhardt]

I use both & a lot of times neither.
A similar thread here @ SMC a couple years back turned me on to using the story pole/stick method.

[Dan Blackshear]

I decided to try metric on my last project and while not intuitive (I am still in the process of retraining my brain to not think in imperial) I did find it to be much more accurate for me. I can safely say after one project I'm a convert, at least for woodworking.

Where it really helped me speed things up is in the design. I use Sketchup, switched it to metric mm and found it much easier to figure ratios and spacing.

Most of my dimensioning tools have metric scales on them already, I just need to get a new tape for my Tablesaw fence.

[Chip Lindley]

Well, maybe not "thousandths of an inch, but tenths and hundreths. Afterall, one-hundredth equals ten-thousandths. 1/100th of an inch is wayy more than these tired eyes can zoom in on! Here is a 12ft. Stanley with fractions AND decimals for the aircraft industry.
http://www.aircraftspruce.com/catalog/topages/tapemeas1.php

[Pat Barry]

I can see no time in the future when I will switch from english to metric. I can't afford the cost of converting completely and until you can completely change it is more trouble than its worth. Couple that with the fact that I am too old to get excited about this (remember this has been talked about for most of the last century and little headway has been made). Finally, just to be fair, I do have the odd tool in Metric because working on my vehicles means I have to get the correct tools. If not for that I would never change at all.

[Ruhi Arslan]

I use barleycorn. It is more accurate. :D

When I was in college, we used both metric and imperial, depending on the subject matter (Aerospace Engineering). In my current profession, we have designs are made with imperial units, manufacturing is made imperial units but all the parts are labeled metric as 5mm, 100mm etc. (Spinal Implants). I still find metric more "logical" and easy to comprehend then imperial. But it is just me.

[Chris Padilla]

Gee Chris can we tell you're from a warm area 10 degrees is cold??????

here's how it works for Canadians

Lemme put it this way: that is how my wife describes those temps. ;) 'nuff said. :D

40 C in Death Valley is interesting...it is a dry heat, though.

[Chris Padilla]

I use barleycorn. It is more accurate. :D

When I was in college, we used both metric and imperial, depending on the subject matter (Aerospace Engineering). In my current profession, we have designs are made with imperial units, manufacturing is made imperial units but all the parts are labeled metric as 5mm, 100mm etc. (Spinal Implants). I still find metric more "logical" and easy to comprehend then imperial. But it is just me.

Yep, in college (electrical engineering), everything was pretty much in metric. Wasn't there a space probe/satellite something or other that went to Mars and burned up due to improper units conversion? Crazy stuff.

[George Bregar]

Imperial.

I mean it all starts with 4/4, 5/4, 8/4. ;)

[mike stenson]

Skip the conversion, like measuring, it just induces error.

[mike stenson]

Imperial.

I mean it all starts with 4/4, 5/4, 8/4. ;)

... and all of those are nominal anyway ;)

[Jonathan Jung]

Switched to 100% metric about 1.5 yrs ago. After the initial getting used to, it's faster and we have less mistakes. Only exception is when conversing with customers.

[Bob Jones 5443]

I remember when I was in junior high school, as it was called then (1970), my science teacher prepared us for America's imminent switch to metric, which would surely come to pass within the next few years.

Hmmm...

In college, my engineering professors were firmly rooted in inches, feet, foot-pounds, feet per second per second, and the like. I only encountered grams and joules in chemistry.

Today I find that making scale plans works well with Imperial and either 4 or 5-square grid paper and an architect's six-sided rule. The numbers are smaller and they fit on the rule (which is itself an absurd opinion).

[Ken Fitzgerald]

Stanley does make a "decimal" tape measure! Using thousandths of an inch rather than coarse fractions (1/64" = .015625") allows for finer woodworking when the occasion arises. IMO, decimal measurements are more useful for machine setup and fasteners than for casework or lumber measurements. Were we to go totally digital, we still have to convert 15/32" plywood back to "thousandths"!



Exactly! It is said you never master a foreign language until you "think" in that language. Converting mentally from one language to the other does not count. I can spread my fingers and show you 3 inches BUT I cannot show you how long 300mm is! Many of us will always "think" in inches, feet, pounds, miles, and degrees F. My grandchildren may be taught to "think" metric, but I never will!

Of course, I can convert inches to mm. when necesssary, and vice versa. I must do it every day! All imported machinery uses metric nuts and bolts. But, most every other aspect of woodworking in the U.S. is in inches/feet. The building trades still use lots of inches and feet. A wall stud is 8 ft. long. A sheet of plywood or MDF is 4x8 ft. 12-2 wire comes in a 250 ft. roll! etc, etc.

A cubic meter of concrete? How many kilometers per liter does your new truck get? Until every quantity and size is offered ONLY in metric measurement, the two systems Will be obliged to coexist. Our infrastructure in the U.S. is firmly entrenched in the inch/pound system, in more ways than we can imagine.

Stanley also makes a metric/imperial tape measure. I used one in my professional career. The medical field in the US has been in metric for quite some time and I used metric as much or more than inches in my professional life.

In the '60s, the HS chemistry and physics classes I took were taught in metric as we were told the US was going to metric as it made more sense, was easier to use and the rest of the world was using it or converting to it. Nothing jacked my jaws worse when I was still doing my own auto mechanics than buying my first new car that had both metric and SAE bolts and nuts. Way to go Detroit! Great decision! Well, other American businesses including my future and now former employer did the same thing. As a field engineer, I had to carry, you guessed it, 2 sets of tools, metric and imperial. In reality, it isn't that difficult.

An 8' wall is 2,438.4mm or 24.384cm or 2.438m.

Like a lot of things in life, making the decision is more difficult than living with the results of the decision.

(Providing, of course, it's the right decision in the first place!:o)

[Jimmy Harris]

It makes no difference to me either way. And to me, there are three measurement systems: Imperial with fractions, Imperial with decimals, and Metric. The only problem I have is trying to use both at the same time and converting between them. Especially since some machines only go to two decimal places. So is 1/8th .12 or .13? It usually doesn't matter, but sometimes it really does.

So long as I can stick to one or the other, I'm fine. But I use imperial with fractions most often, as that's how most of my tools are set up. But, if I had a choice to customize all of my tools, I'd prefer metric.

[Bill Dufour]

And -40 is cold cold cold.
Bill D

[George Yetka]

Feet and inches are good math practice.

[mike stenson]

Feet and inches are good math practice.

I do a whole lot of math in hex, and a whole lot of higher order math. Fractions? meh.

I'd rather practice multiplication, subtraction, and remainder skills while imbibing in beverages and throwing pointed items.

[Alan Lightstone]

Gee Chris can we tell you're from a warm area 10 degrees is cold??????

here's how it works for Canadians

-40 Intersection of F and C scales, good ice fishing hut weather

-30 Time to wear long underwear

-20 Nice winter carnival weather

-10 Time to zip up jacket

0 can't use the porch as a freezer any more, plaid shirt weather, no more jackets

5 motorcyle weather again

10 t shirt weather

20 Warm weather

30 uncomfortably hot weather

40 why would anyone live where it gets to 40?

regards, Rod.
ROTFLMAO

In the cardiac OR, we have different feels for temperature.

39 Boy this patient must be very septic. Anyone have some serious antibiotics?
37 Nice, warm and toasty. Living.
35 Damn, I hate that the surgeon keeps the room so cold. Get me a Bear Hugger / warming blanket. And a blanket for me too.
31 Heart's gonna stop any time now. Ruh, Roh... Damn, there it goes. V Fib.
28 Aren't we gonna warm up the heart soon and get off cardiopulmonary bypass??
21 Man, we're putting ice around the brain now. God it's cold in here. Aren't we gonna make him undead any time soon?

Totally different / weird view of temperature. But one I lived with every day. Never had a clue about the temperature outside the OR. Usually hot enough to fry an egg on the pavement, but we were clueless.

I use metric exclusively for woodworking now. Just easier to divide things in half, etc...

[Doug Garson]

I chuckled when I look at this thread today and saw Rod's comment in 2010 "40 why would anyone live where it gets to 40?" I looked it up and Lytton BC set a new record at +41.4C last year which was the highest temperature anywhere in Canada.

[Rod Sheridan]

I chuckled when I look at this thread today and saw Rod's comment in 2010 "40 why would anyone live where it gets to 40?" I looked it up and Lytton BC set a new record at +41.4C last year which was the highest temperature anywhere in Canada.

Hi Doug, that temperature, and the fire were difficult to comprehend for Canadians, we’re really managing to cause serious climate change.

Regards, Rod

[Stan Calow]

It was an old thread, but still seems to be alive. I too was taught in both systems in high school and college. I think it's pointless to focus on conversion formulas or rules of thumb. It's what you get used to seeing. Probably most people have a good feel by now of how big one or two liter bottle of soda is, for example. You dont have to convert it. Being anti-metric on principle is futile. Much of what we think is in inches and feet, like plywood and car parts, are already metric, we just dont know it. It's a world market and like it or not, the US doesn't set the world's standard any more.

[Michael Burnside]

Old thread, but not as old as this discussion. I find the arguments either way entertaining. Metric or imperial, I often use a calculator to confirm my measurements just as I do in my real job. I'd hate to tell my boss we need to repsin this project for 300k because "I did the math in my head". I know wood isn't millions of dollars, but checking with calc pro takes seconds and could save you a lot of time if you mess up. I've been known to screw up base 10 math just as easy in my head :)

And whatever you do, you should not convert back and forth, that's just asking for problems and is a stupid argument for either side.

I don't know about ya'll though, once I get my base measurements in, it's all unitless relative measurements anyway. :rolleyes:

[Maurice Mcmurry]

On any digital device I always use Metric. On every analogue device I always use fractional inches. Finding a center is another time that I use mm

[Jim Becker]

Measurement systems are measurement systems. They all have value to the user. The only good universal rule is "don't mix them in a project".

I'm 100% metric in the shop unless i'm doing something for a friend who's specifications are in inches and 95% inches/feet for construction. After five years, I'm no longer mentally visualizing the conversion anymore, other than in long lengths.

[Derek Cohen]

I am conversant with both systems, having grown up with Imperial until I was 10 or 11 years, and then Metric was adopted.

For much of my woodworking life I was pretty solidly Imperial, simply because all the old hand tools (chisels, plough plane blades, drill bits, etc) were Imperial. However, when I acquired a Hammer A3-31, it was Metric, and that changed everything. Somehow the thickness of boards became the foundation for all that followed.

Very gradually, router and drill bits are moving to Metric. The irony is that Metric router bits require a 1/4"- or 1/2" shaft.

Regards from Perth

Derek

[Brian Holcombe]

I prefer to measure in decimal inches over anything. My equipment is european so aside from router bits, everything is in metric.

Alternatively, you can just make everything a multiple of 8mm (5/16") and you'll be working metric and imperial at all times. :D

[Bill Howatt]

...
Very gradually, router and drill bits are moving to Metric. The irony is that Metric router bits require a 1/4"- or 1/2" shaft.
...
Derek
And my metric sockets use a 1/4, 3/8 or 1/2" drive ratchet.

[mike stenson]

And my metric sockets use a 1/4, 3/8 or 1/2" drive ratchet.

Gotta love legacy standards.

I have a die grinder with a metric collet, it sucks because finding metric bits is a pain.

[Jim Dwight]

I have no problem at all with people who prefer metric. It is a good system - for them. But I do have a problem with them or anybody else saying metric is a "better" system. It is not for me. I grew up with feet, inches, and fractions. I cannot envision how big something 27cm is unless I convert it to inches. I cannot envision how much 3 kg is unless I convert it to 6.6 pounds. But for those who know what 27cm is and what 3kg is, go for it.

The best way to measure, however, is not to do it. If it wasn't so cold in my unheated shop I would be there right now cutting down a couple 2x4s to fit the rails on a bed I am making (I use cheap 2x4s to support the slats which support the mattress because they are cheap, sturdy enough, and won't be seen). They need to be the same length as the bed rails and I have a stop already set for that. So the same stop will be used. Any time you can measure off a part you want to mate up to you should. Much less chance of error that way. Story sticks are another way to help minimize errors. You have to do the measurements once in many cases to make the stick but then you can reuse it for all the dimensions in the project that length. Regardless of how you measure - which system you use - measuring is an opportunity to make a mistake.

Trying to force others to use the system YOU prefer is just silly and immature. It pushes them in the direction of mistakes. I can use metric, I have to to use my domino which I love for making mortises, but I prefer to use the system I can visualize better. I don't think it's inherently better or worse than metric, it is just what is easiest for me to use.

[Justin Rapp]

A lot of my tools are Inches (table saw scale, router bits, chisels, etc.). For that reason alone, I mostly use inches.

--Whit

Same with me. Most tools in the US are in inches, and I got used to doing fractions really well, and even converting from / to fractions and decimals for most of the common sizes but I still need to do a little math when I find something that says 7.28125 inches. Or 7 9/32. I did find this cool chart that has fraction, decimals and MM for every 64th between 1/64 and 1 inch. They sell them on amazon but I found a PDF online and just printed it.

[Lee Schierer]

I use my metric adjustable wrenches all the time. :D

[Michael Burnside]

I just laugh when people talk about how fractions are hard as if that's the argument. If they're hard for you, it's just stick to 16 equal divisions along 1 inch. Instead of 1/2" just use 8/16", instead of 5/8" use 10/16". If you want half of 5/8 it's pretty easy to get half of 10/16, it's just 5 instead of 10, so 5/16ths. Honestly if that's all it is, you're over thinking it. The metric folks that try to pull out a 1/32 or 1/64 just lose credibility, not that it's hard to add 1/32 to 10/16th, which is just half way to 11/16ths, but somehow 16.5mm is easier LOL.

I used metric for a couple of years, but between some tools I really liked being in inches and just not seeing any real value with either system, I just went back to imperial when I decided to refresh the "beginner" tools with "pro" versions and I gave the rest away and replaced with imperial. If there is any argument to be had, honestly I find it easier to see the 1/8 and 1/4 graduations on rules with my eyes, but otherwise, neither has any benefit in woodworking. Elsewhere, I think the argument can be made for metric, just not woodworking.

[Mark Hennebury]

I don't measure anything that I don't have to. I use a knife, a square and a story stick. I have no idea what the actual measurement is. If i have to make a countertop, I template the wall. If I have to fit a built in cabinet I use a story stick and transfer measurements, I use plumb lines and levels, have no idea what the measurement is but I know the cabinet fits the space, and that it is plumb and level. Worked on sailboats interiors, everything is referenced of a centerline. If I am cutting stock same thing, everything is referenced off the stock and transferred, no measurements required. Mortises are cut based on the mortise chisel width, the tenon is made to fit the mortise. I don't care if the mortise is 0.250, 0.255, 0.245 etc, it is what it is, I make the tenon to fit.
You don't really need to measure much at all. Who cares if a table top is 40" +or- 1/16" as long as your joints are tight and all parts are that are supposed to be the same size, are the same size.

[Curt Harms]

There is one other issue I don't believe anyone has mentioned -- hardware. Walk into any U.S. hardware store or home center and peruse the selection and price on imperial hardware compared to metric. Yes they have metric nuts and bolts but smaller selection and bigger price tag. I've never done this in a metric country, it would be interesting to do so.

[Patrick Johnson]

As a designer in the auto industry, I've always designed in metric. In my shop I primarily design and work in inches, sometimes fractions, sometimes in decimal inches.

I think both measurement systems are like a language that you have to learn and become fluent in. If you can do that, it doesn't really matter which system you use.

Patrick

[Brian Holcombe]

Curt, that is typical of hardware store pricing on most things. I usually buy from McMaster Carr, except recently I decided to buy some bolts at the BORG and paid $2.80 for two bolts, not much until you consider that McMaster sells a pack of 50 of the same rated (8.8 4mm bolts) with a detail on COI for $8.50. If I bought 50 at the BORG I'd pay $70 for the same qty of bolts.

[Rob Luter]

I've used decimal inch for 40+ years. I'll take that to my grave.

[Maurice Mcmurry]

These little rulers are very helpful. Now if I can learn to keep track of my glasses. I need to find a metric ruler and metric tape measure. A poster size cheat sheet would be nice to have too.

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[Jim Becker]

Maurice, both dual scale rulers and tapes are readily available as are metric only. For the tape, I like the FastCap (yellow label) as it actually stays out until you hit the button to retract. My dual scale rulers are from Lee Valley and are excellent. I acquired replacement metric rules for my squares from Lee Valley, too. I find having dual scale to be very helpful, even though I primarily work in metric. Not only does it mean the same measuring tools can be used regardless it also helps with visualizing the odd longer lengths which are "less natural". It's like learning a language when one didn't grow up speaking it (which is the case for many of us in the US, despite metric being heavily used in industry and science for a very long time now)...you learn a whole bunch of language up front but some of the more advanced grammar takes longer.

[Harold Patterson]

I think in inches so decimal inches have worked for me as I don’t have to deal with fractions.

[Chris Parks]

Maurice, both dual scale rulers and tapes are readily available as are metric only. For the tape, I like the FastCap (yellow label) as it actually stays out until you hit the button to retract. My dual scale rulers are from Lee Valley and are excellent. I acquired replacement metric rules for my squares from Lee Valley, too. I find having dual scale to be very helpful, even though I primarily work in metric. Not only does it mean the same measuring tools can be used regardless it also helps with visualizing the odd longer lengths which are "less natural". It's like learning a language when one didn't grow up speaking it (which is the case for many of us in the US, despite metric being heavily used in industry and science for a very long time now)...you learn a whole bunch of language up front but some of the more advanced grammar takes longer.

When Australia went metric visualising the measurement was the hardest thing to do but I found using familiar items helped. A 6" rule is 150mm and a 12" is 300mm, a yard is very close to 39" etc. I was dragged into metric when the plans for my workshop arrived and by the time I finished I was convinced that metric was the way to go.

[Jim Becker]

When Australia went metric visualising the measurement was the hardest thing to do but I found using familiar items helped. A 6" rule is 150mm and a 12" is 300mm, a yard is very close to 39" etc. I was dragged into metric when the plans for my workshop arrived and by the time I finished I was convinced that metric was the way to go.
Yes, that's how I've managed the migration over the past 4+ years. It's only the "long lengths" that remain challenging, but it's not a concern because I measure things. :)

[Maurice Mcmurry]

Maurice, both dual scale rulers and tapes are readily available as are metric only. For the tape, I like the FastCap (yellow label) as it actually stays out until you hit the button to retract. My dual scale rulers are from Lee Valley and are excellent. I acquired replacement metric rules for my squares from Lee Valley, too. I find having dual scale to be very helpful, even though I primarily work in metric. Not only does it mean the same measuring tools can be used regardless it also helps with visualizing the odd longer lengths which are "less natural". It's like learning a language when one didn't grow up speaking it (which is the case for many of us in the US, despite metric being heavily used in industry and science for a very long time now)...you learn a whole bunch of language up front but some of the more advanced grammar takes longer.

The FastCap looks perfect! Thanks, I ordered 3, one for me and 2 for the young men. Hoo-ray for Acme Tools!

[Jim Becker]

The FastCap looks perfect! Thanks, I ordered 3, one for me and 2 for the young men. Hoo-ray for Acme Tools!
I really like the FastCap tapes. I don't use tapes for critical work, but they still have a place for sure. And the dual scale version covers all the bases for me. I'll likely get another for in the house/garage at some point and donate a few of the old tapes that have seen better days. I bought my FastCap tape on Amazon.

[Bill Howatt]

Just to deviate bit from inches vs mm, what I love about the metric system has to do with weight/volume units perhaps more useful in the kitchen than the shop but still applicable to mixing shop things too.
In Canada, we are probably sitting on the fence (pickets, actually) because of our proximity to the US.
Add 5 ounces of x, is that liquid 5 ounces or weight ounces - this vagueness is not a metric issue alone, but using metric makes it go away.
Mix a gallon of banana oil into the dry ingredients - is that a US gallon (3.8 liters) or an Imperial gallon (4.54 liters)
Pour in 1 cup of water - is that a US cup (1/2 US pint, 236ml) or an Imperial cup (250ml)

While I'm at it, another source of major confusion here is date format.
In US, the common form is Month-Day-Year so today (Feb 12) is 02-12-2024
In Canada, what is sort of the common form is Day-Month-Year or 12-02-2024 although officially we are supposed to use the metric form.
So when we see a numeric only date there is uncertainty unless the day is 13 and up because we get information both within Canada and the US.
If everybody standardized on the metric form of YYY-MM-DD it would help a lot but...

[mike stenson]

Just to deviate bit from inches vs mm, what I love about the metric system has to do with weight/volume units perhaps more useful in the kitchen than the shop but still applicable to mixing shop things too.
In Canada, we are probably sitting on the fence (pickets, actually) because of our proximity to the US.
Add 5 ounces of x, is that liquid 5 ounces or weight ounces - this vagueness is not a metric issue alone, but using metric makes it go away.
Mix a gallon of banana oil into the dry ingredients - is that a US gallon (3.8 liters) or an Imperial gallon (4.54 liters)
Pour in 1 cup of water - is that a US cup (1/2 US pint, 236ml) or an Imperial cup (250ml)

While I'm at it, another source of major confusion here is date format.
In US, the common form is Month-Day-Year so today (Feb 12) is 02-12-2024
In Canada, what is sort of the common form is Day-Month-Year or 12-02-2024 although officially we are supposed to use the metric form.
So when we see a numeric only date there is uncertainty unless the day is 13 and up because we get information both within Canada and the US.
If everybody standardized on the metric form of YYY-MM-DD it would help a lot but...

DD-MM-YY is far more common world wide. I don't think people want to deal with years first. Since I work in an industry in which timestamps are a thing, I'd just like them to be the same. I guess we could just use Epoch, in which case it is currently ​1707749123

[Rod Sheridan]

DD-MM-YY is far more common world wide. I don't think people want to deal with years first. Since I work in an industry in which timestamps are a thing, I'd just like them to be the same. I guess we could just use Epoch, in which case it is currently ​1707749123

Hi Mike, I thought the ISO standard was YYYY/MM/DD?

Regards, Rod.

[Michael Burnside]

DD-MM-YY is far more common world wide. I don't think people want to deal with years first. Since I work in an industry in which timestamps are a thing, I'd just like them to be the same. I guess we could just use Epoch, in which case it is currently ​1707749123

As a programmer I much prefer YY-MM-DD/YYYY-MM-DD as it will always naturally sort. As of this post current time is 1707751826

[mike stenson]

Hi Mike, I thought the ISO standard was YYYY/MM/DD?

Regards, Rod.

It is, however, ISO standards are not really what is in common use. We're still humans, and working in a completely international environment I've found that two things make things clearer in terms of day/date.

Using the more common DD/MM/YY format, and also using a 24 hour clock.

logs being consistent? if I ever see that it's time to retire.

[Doug Garson]

Yeah, the date format can be confusing, I recall decades ago I was at customs in London Heathrow airport. When I presented my passport the agent wished me happy birthday, when I looked confused he said yeah you colonials use a different date format. The date was Nov 3rd and my birthday is March 11th. Maybe alpha numeric format is the way to go, much less chance for confusion.

[Bill Howatt]

To be honest, the alpha numeric format is what I prefer seeing although now that some YY has crept into usage as the first number, there can be year and day confusion such as with 17-Aug- 21, so a 20 for this century needs to be added to one of them. To be real honest, I did this to myself with some old partially turned wood that I wrote the date on a few years ago and which number I consider as the year is plausible. Fortunately, it isn't much of a practical issue.