reading metric tape measure

[Dave Lehnert]

When reading a metric tape measure. Do you record a measurement as, for example, 12MM or 1cm and 2mm. Reason for my question, If giving a measurement to someone who is use to the metric system, what will they expect to hear?

[John Densmore]

1.2 cm or 12 mm.

[Rick Fisher]

In that case, 12mm

Eh ..

[Dennis Aspö]

When reading a metric tape measure. Do you record a measurement as, for example, 12MM or 1cm and 2mm. Reason for my question, If giving a measurement to someone who is use to the metric system, what will they expect to hear?

I never know what to expect, sometimes it's millimeters, sometimes centimeters, sometimes its meters. People use whatever they feel like, I also swap between units all the time, it depends mostly on what the scale I am using says, I tend to use cm if the scale is graduated in CM.

In the end it doesn't really matter because converting between them in your head is super easy.

1000mm (thousands of a meter, or tenths of a cm)
100cm (hundreds of a meter)
1m

[Pat Barry]

I think if you look at the dimensions for common metric products you will find that they are always stated in mm. Centimeters are a largely unimportant denomination since the mm value provides you everything you need to know. If the dimension is over a meter then use the convention m,mm; for example 1 meter, 66 mm - 1,66.

[Von Bickley]

I don't have that problem...... I'm too old to mess around with a metric system.

[Jason Roehl]

I think if you look at the dimensions for common metric products you will find that they are always stated in mm. Centimeters are a largely unimportant denomination since the mm value provides you everything you need to know. If the dimension is over a meter then use the convention m,mm; for example 1 meter, 66 mm - 1,66.

In European and Latin-American countries (and perhaps much of the rest of the world), usage of the comma and decimal point is reversed from what we know in the U.S. That is, two hundred thousand and thirty-four hundredths would be written, "200,000.34" in the U.S., but written, "200.000,34" in other countries. It's kind of weird if you ask me. But, then again, if someone said, "two hundred thousand and thirty-four," most of the time in the U.S., they would mean, "200,034".

I see plenty of dimensions from foreign companies listed in mm, even somewhat larger ones--plywood might be 1200mm x 2400mm, for example. I don't think I've ever seen a dimension listed as "1cm and 2mm" though--that kind of defeats a major purpose of the metric system--the easy decimal point manipulations.

[Mel Fulks]

In school we were taught ,as an example, "3 meters,2 decimeters, (etc)". Many of us have seen dimensions such as
" 36,652 milimeters ".

[Andrew Pitonyak]

I don't have that problem...... I'm too old to mess around with a metric system.

That is the long answer to "record it as 0.472441 inches" :D

[Bill Orbine]

It drives me nutty when I read dimensions on architectural blueprints in foot and inches so I often convert to inches only. For example, if the print says 4'-11 1/2", I find it easier to read it as 59 1/2" and I will write that in on the print. Practically everything I do in woodworking is in inches with fractions. Easier for me. I sure if you put down metric dimensions in meters, centimeters and millimeters, I'd have a brain attack! Keep it simple!

[Brian Deakin]

That is, two hundred thousand and thirty-four hundredths would be written, "200,000.34" in the U.S., but written, "200.000,34" in other countries. It's kind of weird if you ask me. But, then again, if someone said, "two hundred thousand and thirty-four," most of the time in the U.S., they would mean, "200,034".

In the Uk. the number would be written 200,034

Large whole numbers have a comma placed every 3rd number counting from the last number on the right

eg 10000000000 becomes 10,000,000,000

length if in a whole number of centimetres would be written 45cm or 450mm If the length was not a multple of 10cm then the length would be written in mm eg. 452 mm and not 45.2cm

If the length was greater than a metre then either 1.5m or 1500mm


regards Brian

[Rich Enders]

A part of our life is design work for molded plastic components, and for the tooling and fixtures used in their manufacturing. Our customers are scattered around the world and in the US. The metric system predominates throughout (even in the US), and the millimeter (mm) is the unit of choice. The CAD program that we use allows two default units: Inches, or millimeters.

Size wise our projects are not so large so that may be why we all use mm. Probably someone designing a house (or a bridge or a city) would use some other unit. I don't think I have ever seen centimeters or meters used in our world even though injection molds can be several thousand in mm's.

[Halgeir Wold]

Construction and design drawings are mostly in mm over here, but in daily practice meters and/or centimeters are often used. It's just a habit, as anything else.....
what looks weird depends on the eyes looking.. :-) Some of us works in "mixed" environments, and really have no problems doing both systems-
And - BTW 45,2 cm is a very common way of speech and writing for most people outside professional environments.
I think it is also correct that meters and millimeters are wordlwide dominant, whether some of you guys like it or not... ( OMG - here we go again.......) :D

EDIT: 36,652 milimeters, - thousands of a millimeter is a mighty tight tolerance..... 0.001mm equals 0.0397 mils......

[John Stankus]

Since I am sitting here working on prepping my Fall classes, I happen to have my Chemistry professor hat on. The metric system is really not that hard. I acknowledge that folks are comfortable with what they are used to, but in terms of ease of use metric has it hands down.

Here are two questions that illustrate my point.
1) How many inches are there in 1.5 miles?
2) How many centimeters are there in 1.5 kilometers?

You can calculate both easily, but with the second the math is so trivial that is easily done in your head.



John
(in the spirit of full disclosure, my shop is in imperial since the tools are in imperial)


That's what is great about standards, everyone has their own. :)

[Albert Lee]

We use metric down here but when it comes to a person's height it is very common to use imperial units....

[Roy Harding]

In my experience, all woodworking (and architectural) measurements are in millimetres. Centimetres are rarely used, and you don't get into metres until you are measuring things that would be expressed in yards in the imperial system (IE, if something is five feet long, you don't state it as "1 yard, 2 feet")

[Andrew Pitonyak]

Cubits, always use cubits....


I think it is also correct that meters and millimeters are wordlwide dominant, whether some of you guys like it or not... ( OMG - here we go again.......) :D


No idea what is predominant, but I have been told (with no particular evidence) that metric has greater use, which is against the odds since it was developed by a committee. Now, whenever I have to deal with a spherical cow, I am almost always using MKS (http://en.wikipedia.org/wiki/Spherical_cow).

For the most part, I don't really care other than the fact that most of my expensive measuring equipment is not set for metric.

It is difficult to argue that decimals are just easier to deal with than fractions, especially with large denominators.

It is nice to have both bits for when you need a size that is right between something that you already have. So, if you don't really want to go up 1/64th and the base value is in English measure, the drop to those mm bits (and vice-versa).

[Dave Lehnert]

A part of our life is design work for molded plastic components, and for the tooling and fixtures used in their manufacturing. Our customers are scattered around the world and in the US. The metric system predominates throughout (even in the US), and the millimeter (mm) is the unit of choice. The CAD program that we use allows two default units: Inches, or millimeters.

Size wise our projects are not so large so that may be why we all use mm. Probably someone designing a house (or a bridge or a city) would use some other unit. I don't think I have ever seen centimeters or meters used in our world even though injection molds can be several thousand in mm's.

The reason asking about the metric system, My new position at work will be involved in wiring electric panels for international customers that use the metric system.
Does it make a difference if we are talking measuring electric cable to length?

[Shawn Pixley]

When I was doing architecture in metric, all dimensions on the plans were in MM. Now that I review other plans from around the world, all are still in MM. Even chinese plans use arabic numbering (in MM).

I grew up the son of a scientist and studied chemistry in my undergrad years so metric is pretty second nature to me. It really does make things easier when calculating fundamental equations that represent the physical world.

[Dennis Aspö]

Someone said centimeters weren't used a lot but I find they are in use all the time. In lots of manuals, usually by bigger companies , things are in millimeters. But in every day use centimeters are common as a scale that is useful in a lot of evey day applications.

Also tape measures are graduated in centimeters and last night we did some actual woodworking, cutting panels and stuff when assembling a cabinet with sliding mirror doors and installing a dishwasher etc., the unit we used where centimeters, we talked about millimeters too when it was suitable (for adjustments less than 1cm).

Centimeters is also the common way to refer to height here, some other countries I think might use meters instead, like in Finland I'd say I am 188cm tall, but in some other country they might say they're 1.88 meters tall. I don't know if anyone uses mm for stuff like this.

[ray hampton]

Someone said centimeters weren't used a lot but I find they are in use all the time. In lots of manuals, usually by bigger companies , things are in millimeters. But in every day use centimeters are common as a scale that is useful in a lot of evey day applications.

Also tape measures are graduated in centimeters and last night we did some actual woodworking, cutting panels and stuff when assembling a cabinet with sliding mirror doors and installing a dishwasher etc., the unit we used where centimeters, we talked about millimeters too when it was suitable (for adjustments less than 1cm).

Centimeters is also the common way to refer to height here, some other countries I think might use meters instead, like in Finland I'd say I am 188cm tall, but in some other country they might say they're 1.88 meters tall. I don't know if anyone uses mm for stuff like this.

Do you use the metric method when you measured the height of a race horse ?
I prefer the simple method

[Ken Kortge]

I work for a German global company, but live in the U.S., and I'll agree with Jason ... You should be more concerned with the risk of misunderstanding the decimal place due to the fact that the U.S. uses the period to indicate decimal place and periods to indicate 1000's ... where much of the rest of the world uses the comma to indicate the decimal place and commas to indicate 1000's.

Unfortunately there does not appear to be any global agreed upon solution to this issue.

The best solution is to try to avoid decimal places all together. So certainly provide 120 mm rather than 1.2 cm, because in Europe that would be written as 1,2 cm.

If you want to provide 120.3 mm, then you really only have two choices - provide "120.3 mm" or 120,3 mm".

I have stopped using thousands separators (commas in the U.S., periods in other places) since they only add to confusion.

I am also careful not to provide three decimal places ... because that can be confused with the thousands separators.

For example "123.456 mm" could be misinterpreted as just over 123 mm OR just just over 100000 mm.

For the value 123.456 mm, I'll convert to a different type of unit to avoid the three decimal places. So 123.456 mm becomes 12.3456 cm ... or even better 123446 um (or micrometers). The typical users will have to do some conversion if you are using micrometers, but they will know exactly what you mean.

[Mel Fulks]

Old subject, so I'm not complaining ...just pointing out that in grade school we were told that system was standard in the
rest of the world. Not true. Some use only pieces of it ,so it's not a metric system it's a metric menu. The English system is at least a true system, have not seen any evidence of anyone insisting on using only sixteenths or eighths.

[Mark W Pugh]

I don't know about everyone else, but since I was never raised with the metric system, it is hard for me to mentally visualize something given in metric. I would love to adopt the metric system, which I think would be easier in the long run, but I just need to get my head around the mental conversions. Hopefully that makes sense.

[Halgeir Wold]

With the risk of fueling the discussion, - or just another one in the row, but except for habit, I cannot see what is so difficult with metrics. It is not a menu, but a complete system, as it encompasses all types of measurements, and everything is based on the powers of ten. This is also the reason it has become the basis for the SI system which rules the science world. It is also a fact that even the US is "metricated" in lot of different areas.

It is quite correct that is was designed by a committe, albeit a scientific one, with the mandate to unify a totally bewildering mess of similar units with different values, hampering both trade and work. These different values of units were also to a large extent the basis for direct fraud. Even over here, 100 years ago or thereabouts, there were 3 different "thumbs", as was the local name of the unit. There were norwegian and danish "thumbs", and british inches, - and there was actually also a swedish version. Builders of historic boats still use the old thumbs and alens, as they are the very basis for the proportional system used in building these boats. Old geezers like me still uses 2x4s for simple timber framing, and not 48x96 (mm) which is the modern version for dimensioned lumber, and to our parent generation a 2x4 was really a 2x4..

Looking at the british system around 1800 or so, an inch was not the same inch all over, and a pound didn't weigh the same throughout the country.
Add to that all the different divisors used in lenght, volume and weight, this overall system, or lack thereof, looks by far a lot more like the political commitee which was given the task of building a horse..... and alas, that's when we got the camel....... < Ducking and running... >

( Sorry guys - I just could not resist... :D )

[Dennis Aspö]

Do you use the metric method when you measured the height of a race horse ?
I prefer the simple method

I don't know what this means?

[Dennis Aspö]

I work for a German global company, but live in the U.S., and I'll agree with Jason ... You should be more concerned with the risk of misunderstanding the decimal place due to the fact that the U.S. uses the period to indicate decimal place and periods to indicate 1000's ... where much of the rest of the world uses the comma to indicate the decimal place and commas to indicate 1000's.

Unfortunately there does not appear to be any global agreed upon solution to this issue.

The best solution is to try to avoid decimal places all together. So certainly provide 120 mm rather than 1.2 cm, because in Europe that would be written as 1,2 cm.

If you want to provide 120.3 mm, then you really only have two choices - provide "120.3 mm" or 120,3 mm".

I have stopped using thousands separators (commas in the U.S., periods in other places) since they only add to confusion.

I am also careful not to provide three decimal places ... because that can be confused with the thousands separators.

For example "123.456 mm" could be misinterpreted as just over 123 mm OR just just over 100000 mm.

For the value 123.456 mm, I'll convert to a different type of unit to avoid the three decimal places. So 123.456 mm becomes 12.3456 cm ... or even better 123446 um (or micrometers). The typical users will have to do some conversion if you are using micrometers, but they will know exactly what you mean.

Honestly it's never been an issue for me, context helps me determine if the dot or comma is meant as a decimal or not most of the time.

[John Stankus]

Metric is definitely a complete system. The metric systems formal name is the international system of units(SI comes from the French) The foundation is seven base units that everything else is derived from. Meter, kilogram, second, ampere, kelvin, mole, candela

Also do realize that the pound and the yard have been based on metric standards since before 1893 by the Mendenhall order. The NIST we page has a history of measurement in the US.

As for visualizing metric units, cut a couple of scrap pieces to 5, 10, 20 cm etc lengths and label them. Having physical artifacts helps getting used to the sizes.

John

[John Stankus]

Do you use the metric method when you measured the height of a race horse ?
I prefer the simple method

That's easy since a hand is 1.016 decimeters.

For our friends from places other than the former British empire, a hand is a traditional English unit of measure used to measure how tall a horse is. A hand is 4 inches or 1/3 of a foot, or 4 4/7 fingers, or 5 1/3 digits, or 12 barleycorns or 48 poppy seeds or 48 lines or 1/9 of a yard. In metric the hand would be 0.1016 meters, or 1.016 decimeters or 10.16 centimeters or 101.6 millimeters. So which is the simpler system? I think it is familiarity not simplicity that folks are comparing on.

John

[ray hampton]

That's easy since a hand is 1.016 decimeters.

For our friends from places other than the former British empire, a hand is a traditional English unit of measure used to measure how tall a horse is. A hand is 4 inches or 1/3 of a foot, or 4 4/7 fingers, or 5 1/3 digits, or 12 barleycorns or 48 poppy seeds or 48 lines or 1/9 of a yard. In metric the hand would be 0.1016 meters, or 1.016 decimeters or 10.16 centimeters or 101.6 millimeters. So which is the simpler system? I think it is familiarity not simplicity that folks are comparing on.

John

thank you JOHN for the example
if you are familiar with a certain method then it become a habit to follow for the same results time after time SO IT became simple

[John Stankus]

thank you JOHN for the example
if you are familiar with a certain method then it become a habit to follow for the same results time after time SO IT became simple

Any system of measure is fine if you use it consistently. Noah built in cubits and he probably was perfectly comfortable using those units. I would initially have a tough time with cubits, but the unit of measure really doesn't matter. For one-offs a story stick is probably better than any particular system.

Measurement systems are actually pretty arbitrary, they just need to be agreed upon by those who use them. I could easily define a measurement system based on one brick, let's call it John's masonry Scale. The length unit is based on the length of that particular brick, and the mass unit is based on the mass of that particular brick. Maybe I am a fan of base 5 number systems, so the bigger and smaller units are all related by 5n. I could use this system to pretty much build anything (though I would question the stability of my standard).

Reminds me of my father's temperature scale. "Degrees S" The temperature degrees are the same size as Fahrenheit scale, but the scale is shifted so that 0oS =72oF


The real issue actually comes from the switching between systems of measurement.
See: The Gimli glider, the Mars Climate Orbiter loss, Tokyo Disneyland roller coaster derailment, etc

John (who probably should get back to prepping his Fall classes)

[Curt Harms]

I don't know about everyone else, but since I was never raised with the metric system, it is hard for me to mentally visualize something given in metric. I would love to adopt the metric system, which I think would be easier in the long run, but I just need to get my head around the mental conversions. Hopefully that makes sense.

I find this helps me when looking at things like fasteners. They're approximate but get me in the ballpark.

1/4"=6mm
5/16"= 8mm
3/8" = 10 mm
1/2" = 12 mm
3/4" = 18 (or 19) mm

1 mm is 1/25.4" or halfway between 1/16" and 1/32". I doubt woodworkers use measurements much finer than .5 mm.

A meter's a little over a yard.

What I'm not at all familiar with are units of pressure and power. For example I don't have a good grasp of the metric equivalent of 1 h.p. or 40 p.s.i.

[Chris Padilla]

I find this helps me when looking at things like fasteners. They're approximate but get me in the ballpark.

1/4"=6mm
5/16"= 8mm
3/8" = 10 mm
1/2" = 12 mm
3/4" = 18 (or 19) mm

1 mm is 1/25.4" or halfway between 1/16" and 1/32". I doubt woodworkers use measurements much finer than .5 mm.

A meter's a little over a yard.

What I'm not at all familiar with are units of pressure and power. For example I don't have a good grasp of the metric equivalent of 1 h.p. or 40 p.s.i.

1 m is 39"...again, an oddball number. 19 mm is closer to 3/4" than 18 mm. 13 mm is closer to 1/2" as well although I guess it depends on the direction you're coming from (you want it greater than or less than) and what you are doing. 3 mm is 1/8". 3/8" is almost dead on at 9.5 mm. :D

In large distances, you NEVER hear Mm (Megameters) or Gm (Gigameters) but you see stuff like 1,000,000 km. I see mm, cm, and m all the time. Also, um (Greek mu letter) for micrometers (I'm a EE working on silicon chips).

We have "mil" for 1/1000 of an inch or 10^-3 inches. 1000 mil per inch--some like to say "thou" for thousandth. 1 mm ~ 40 mi; 25 mm in an inch. These are very common in the electronics world.