Why Metric? I realize that the metric system is much simpler. After all what genius decided that 11/64ths was the way to go? I wondered why every STL file I download is in mm? I use Rhino 3D and always draw in inches. Am I the only one? https://reprap.org/forum/read.php?1,475880,475880#msg-475880 Mon, 20 Apr 2026 11:40:42 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?1,475880,476838#msg-476838 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476838#msg-476838 For those of us that can (USA) we own two markets.

I think it is a way for USA to own the USA business and Euro business. USA manufacturing use any system, you want feet, fractions, hectometers, cubits, we will quote it.

Others may need a metric print....

Metric hardware generally costs more.

What is a metric pipe thread?

What are metric rivets?

I see converted metric units that have their foundation in imperial but want to seem metric without the added cost of re-tooling something that built modern industry and works well.

Engineering is a blend of needs and wants. If we understand our customer it does not matter if we call it 7/32" or .375mm. USA companies play both sides equally well. Euro companies tend to be metricentric, probably wouldn't quote imperial prints.

More work for USA, why throw out 200 years of machine tools and inspection equipment? It may be more important when getting down to splitting atoms, but most things aren't that. I work in anything, I work. Bring on your 9/16th of a decimeter, I understand and will make it in print.

Who cares if you call it 1.75 mm or .0688795" either way after about 3 or 4 decimal places, it wont matter. It is the same dimension. You can't print that close anyway!]]> kengineer General Fri, 27 Feb 2015 19:51:03 -0500 https://reprap.org/forum/read.php?1,475880,476785#msg-476785 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476785#msg-476785
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dclarkm
I'm sure you know, but the Imperial measurement system is hardly Base 12.....

... I think, he's referring to "dozens", an ancient counting and measure system, which was replaced by the metric system ages ago, but is vivid in some dialects and kitchen measures until today ;)]]> VDX General Fri, 27 Feb 2015 16:16:09 -0500 https://reprap.org/forum/read.php?1,475880,476775#msg-476775 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476775#msg-476775
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tmorris9
I am 50 and always worked in fractions and decimals. Since I got into 3D printing I am learning metric and I really, really wish the U.S. had switched over to metric like they said they were going to when I was in grade school. It is base 10 not 12 and it is just so much easier.
Jimmy Carter tried to tell us.....(go figure!)

I'm sure you know, but the Imperial measurement system is hardly Base 12.....]]> dclarkm General Fri, 27 Feb 2015 15:48:25 -0500 https://reprap.org/forum/read.php?1,475880,476575#msg-476575 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476575#msg-476575
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jaguarking11
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tjb1
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jaguarking11
The answer is simple honestly.

Certain industries adapted one system globaly.

metric = just about every machined or produced article. Even cars built in the US use metric threads/bolts/nuts.

Standard = tiles, plumbing, and certain agricultural equipment.

The world is a mishmosh. At least we are down to small variations that are at least defined. Go look at mpg on a vehicle in the UK and a vehicle in the US. Same car gets higher MPG, the reason? The MPG standard in the UK is different than US.

Uh I work in a very large machine shop and we program everything in decimal inch and every other shop I have worked at used decimal inch. Using metric fasteners does not mean the item was produced with a metric print. Anything we share with other countries is done with dual dimensions.

If you can't handle working with both units, you might not be cut out to be in manufacturing/engineering. It's pretty obvious when something is 1mm vs 1 inch...

Yeah, your a US based machining shop. The world does not beggin or end with the US. I Have lived in the US all of my life, I went from grade school to college here. I am perfectly capable of doing conversions. With that said, the machining shops around the world that use only metric far outnumber the ones that do both or use only standard.

Personaly I am more adapt to doing things in metric than inches or fractions...... I was educated in the us with inches, feet etc. I own tools that are precise that measure in .001 inch, but at the end of the day my metric tools win out.

The US is also very large into manufacturing so do not generalize and say that all of machining is in metric.

I work with inch and metric every day, it's not an issue. If I have a metric dimension I need in Inventor and I am working in an inch template I just type "200mm" and it does the conversion or bust out the calculator and type "200/25.4".]]> tjb1 General Fri, 27 Feb 2015 08:21:56 -0500 https://reprap.org/forum/read.php?1,475880,476472#msg-476472 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476472#msg-476472 VDX General Fri, 27 Feb 2015 03:58:37 -0500 https://reprap.org/forum/read.php?1,475880,476400#msg-476400 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476400#msg-476400 madmike8 General Thu, 26 Feb 2015 22:11:01 -0500 https://reprap.org/forum/read.php?1,475880,476395#msg-476395 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476395#msg-476395 elwood127 General Thu, 26 Feb 2015 20:59:11 -0500 https://reprap.org/forum/read.php?1,475880,476326#msg-476326 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476326#msg-476326
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tjb1
If you can't handle working with both units, you might not be cut out to be in manufacturing/engineering. It's pretty obvious when something is 1mm vs 1 inch...

Funny story. There's a local factory here that makes custom cardboard boxes as a job shop. (Here being the northeast USA.) They have had such a rough time finding qualified help to make boxes that they approached the state to help create a regional training center to make people more employable. The local paper had an aptitude test that nobody applying for work could pass, like "take a 12-inch square, trim 1/8-inch off of all four sides, and tell me what size the resulting square is?" People today are completely lost when they can't punch something into a calculator and have the answer spit out for them. Oh, and this company isn't paying french fry wages. Why teach people to use an archaic system when metric does it for you?

C'mon, even American drug dealers and gang members have gone metric! When was the last time that you ever heard a rapper brag about "cracking a 23/64" into a rival????? :)]]> vreihen General Thu, 26 Feb 2015 17:19:06 -0500 https://reprap.org/forum/read.php?1,475880,476322#msg-476322 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476322#msg-476322
Try getting metric bar stock - it pretty much does not exist. In many metric countries it is still very difficult to get metric tooling as well. Most cutting tools such as slitting saws, drills and unusual endmills are considerably cheaper and more common in imperial. Even if you think you are all metric, the chances are a taper or collet somewhere in the system is actually imperial.

Frankly it doesn't really matter to anyone in manufacturing because when someone gives you a print in mm/inch, the worst case is you click a box on the computer.

Its really only a problem when you are designing an assembly that is forced to mate both imperial and metric components. Every time I have a project that needs both metric and imperial fasteners I feel like punching someone in the face.]]> 691175002 General Thu, 26 Feb 2015 17:07:56 -0500 https://reprap.org/forum/read.php?1,475880,476317#msg-476317 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476317#msg-476317
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tjb1
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jaguarking11
The answer is simple honestly.

Certain industries adapted one system globaly.

metric = just about every machined or produced article. Even cars built in the US use metric threads/bolts/nuts.

Standard = tiles, plumbing, and certain agricultural equipment.

The world is a mishmosh. At least we are down to small variations that are at least defined. Go look at mpg on a vehicle in the UK and a vehicle in the US. Same car gets higher MPG, the reason? The MPG standard in the UK is different than US.

Uh I work in a very large machine shop and we program everything in decimal inch and every other shop I have worked at used decimal inch. Using metric fasteners does not mean the item was produced with a metric print. Anything we share with other countries is done with dual dimensions.

If you can't handle working with both units, you might not be cut out to be in manufacturing/engineering. It's pretty obvious when something is 1mm vs 1 inch...

Yeah, your a US based machining shop. The world does not beggin or end with the US. I Have lived in the US all of my life, I went from grade school to college here. I am perfectly capable of doing conversions. With that said, the machining shops around the world that use only metric far outnumber the ones that do both or use only standard.

Personaly I am more adapt to doing things in metric than inches or fractions...... I was educated in the us with inches, feet etc. I own tools that are precise that measure in .001 inch, but at the end of the day my metric tools win out.]]> jaguarking11 General Thu, 26 Feb 2015 16:51:10 -0500 https://reprap.org/forum/read.php?1,475880,476307#msg-476307 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476307#msg-476307
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tjb1
If you can't handle working with both units, you might not be cut out to be in manufacturing/engineering. It's pretty obvious when something is 1mm vs 1 inch...

Yeah, you'd think that...]]> cdru General Thu, 26 Feb 2015 16:30:40 -0500 https://reprap.org/forum/read.php?1,475880,476301#msg-476301 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476301#msg-476301
quote 'Uh I work in a very large machine shop and we program everything in decimal inch and every other shop I have worked at used decimal inch. Using metric fasteners does not mean the item was produced with a metric print. Anything we share with other countries is done with dual dimensions.'


but not in a machine shop outside of usa right? the world is really really big if you think about it. in fact usa is only 318.9 million out of 6.916 billion people, and only Liberia, Myanmar and United States of America do not use metric. according to the new world encyclopedia, 95% of the population uses metric.

people [www.google.com]
[en.wikipedia.org]
[en.wikipedia.org]
[www.newworldencyclopedia.org]



This all being said, it is quite easy to have your settings in inches and as long as the settings are for the country used for, and the software is setup consistent and there is no questionable doubt inches are used it makes sense to use inches.

However when dealing with a project or a community web site where 95% concencus is to use metric, it makes for a lot fewer headaches if items made to the community in question are set to metric.

so for 3d printed items i stick with metric, for items i cnc and use in usa only. i stick with inches. only convert when absolutely needed and with great caution and double tripple checking, and then some more over a period of days. when your equipment can brake from calculation errors in acceleration speed, cut rate, overload,backlash, run-out, feedrate, jog speed, and spindle speed, it is aweful to convert!!]]> jamesdanielv General Thu, 26 Feb 2015 16:25:21 -0500 https://reprap.org/forum/read.php?1,475880,476275#msg-476275 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476275#msg-476275
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jaguarking11
The answer is simple honestly.

Certain industries adapted one system globaly.

metric = just about every machined or produced article. Even cars built in the US use metric threads/bolts/nuts.

Standard = tiles, plumbing, and certain agricultural equipment.

The world is a mishmosh. At least we are down to small variations that are at least defined. Go look at mpg on a vehicle in the UK and a vehicle in the US. Same car gets higher MPG, the reason? The MPG standard in the UK is different than US.

Uh I work in a very large machine shop and we program everything in decimal inch and every other shop I have worked at used decimal inch. Using metric fasteners does not mean the item was produced with a metric print. Anything we share with other countries is done with dual dimensions.

If you can't handle working with both units, you might not be cut out to be in manufacturing/engineering. It's pretty obvious when something is 1mm vs 1 inch...]]> tjb1 General Thu, 26 Feb 2015 15:31:54 -0500 https://reprap.org/forum/read.php?1,475880,476237#msg-476237 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476237#msg-476237
]]> Srek General Thu, 26 Feb 2015 14:31:23 -0500 https://reprap.org/forum/read.php?1,475880,476187#msg-476187 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476187#msg-476187
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KingRahl
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pushthatbolder
...I have tried importing using imperial and it makes the object 2.5 times bigger...

This is because there are 2.54 cm in 1 inch. The file was exported using a 1/1 scale.

Except that he was pointing out the difference between millimeters and inches, so the factor should have been 25.4, not 2.5.

I admit that when trying to grasp the size of something in my head, I do a mental calculation/estimation into inches. That's what happens when you use one particular system for over 50 years. However, I'm glad that were using the metric system here, and, to me at least, it's kind of embarrassing that America hasn't/can't adopt the metric system. It is a far superior system - at least that's what we were taught back in the 60's when we were being told that it was the future.]]> jbernardis General Thu, 26 Feb 2015 13:22:11 -0500 https://reprap.org/forum/read.php?1,475880,476175#msg-476175 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476175#msg-476175 nophead General Thu, 26 Feb 2015 12:52:04 -0500 https://reprap.org/forum/read.php?1,475880,476161#msg-476161 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476161#msg-476161
Certain industries adapted one system globaly.

metric = just about every machined or produced article. Even cars built in the US use metric threads/bolts/nuts.

Standard = tiles, plumbing, and certain agricultural equipment.

The world is a mishmosh. At least we are down to small variations that are at least defined. Go look at mpg on a vehicle in the UK and a vehicle in the US. Same car gets higher MPG, the reason? The MPG standard in the UK is different than US.]]> jaguarking11 General Thu, 26 Feb 2015 12:09:35 -0500 https://reprap.org/forum/read.php?1,475880,476150#msg-476150 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476150#msg-476150
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KingRahl
Metric is a base 10 system. Easy to calculate.
No, it's just easier for humans because we inherently understand decimal. A computer doesn't do integer, float, or decimal arithmetic in base 10 anyways. It's just the ending result that is converted back to what we understand, base 10.]]> cdru General Thu, 26 Feb 2015 11:37:42 -0500 https://reprap.org/forum/read.php?1,475880,476129#msg-476129 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476129#msg-476129
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elwood127
Sorry about the double post. I thought that I had deleted the first one. I guess not. Thanks for the replies. It sounds like it is time to conform or be cast out. Once again America is wrong thinking that it holds the high ground. That's why an earlier Mars mission inpacted the surface. One guy designing in mm's and another in inches. I'm going to buckle down and set Rhino up for mm's. Something new to learn and that's what it's all about.

No problem. I remember something going wrong majorly with a spaceshuttle because the calculations for a rubber ring in the fuel compartment had strength calculations done in inches while the actual ring was created by using inches or the other way around.

I'm happy to see more and more people adapting to mm's, not because I'm a fanboy, but it's already used a lot, and it's still strange that some things still aren't standard worldwide. Just like liters vs gallons, stones and pounds vs kilograms etc etc.

Maybe in a couple of years... :)

The Metric system has been widely adapted now, here you can see a list of countries that have officially adapted to the metric system:
[en.wikipedia.org]

In the long run, it's probably better (in terms of saving money) for the US to also convert at a point especially when we relate the use of separate systems in co-operations with technology, intercontinental markets and the availability of mechanical parts.

It's painful to let go of things we are used to, but sometimes, to move on, we have to let go of ideas that are dear to us.]]> Ohmarinus General Thu, 26 Feb 2015 10:45:05 -0500 https://reprap.org/forum/read.php?1,475880,476113#msg-476113 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476113#msg-476113

The real fact is that reprap as popular as it is does not have enough people momentum to function if it only uses 1 country.

Also standardization of reprap firmware to use Gcode was brilliant. It allowed reprap to automatically gain understanding from the CNC/machinist world.

Anything that Reprap can do that makes it more aligned with what another agreed upon standard that a big group uses helps.]]> jamesdanielv General Thu, 26 Feb 2015 09:50:50 -0500 https://reprap.org/forum/read.php?1,475880,476034#msg-476034 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476034#msg-476034
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tmorris9
I am 50 and always worked in fractions and decimals. Since I got into 3D printing I am learning metric and I really, really wish the U.S. had switched over to metric like they said they were going to when I was in grade school.

I'm in the same age group, and had the good fortune of living near the Canadian border in the 1970's for grade school. Half of our TV came from Toronto, and half from Buffalo. I lived vicariously through Canada's metric conversion, and was really upset that the yardstick lobbyists squashed the USA metric conversion just as it was kicking off. I vividly remember their weather forecasts in the various media having both temperatures for about a year while everyone adjusted, and then the imperial temperatures were gone. I really wish that we did the conversion with them.

Oh, FWIW, the only non-metric parts on my printer are some 1/2-inch spherical magnets, which were used only because 10mm ones weren't readily available stateside at the time.....]]> vreihen General Thu, 26 Feb 2015 05:54:26 -0500 https://reprap.org/forum/read.php?1,475880,476027#msg-476027 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476027#msg-476027 Traumflug General Thu, 26 Feb 2015 05:39:40 -0500 https://reprap.org/forum/read.php?1,475880,476023#msg-476023 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,476023#msg-476023 VDX General Thu, 26 Feb 2015 05:28:12 -0500 https://reprap.org/forum/read.php?1,475880,475969#msg-475969 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475969#msg-475969
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pushthatbolder
Yes i know that. I was just stating it to support my post.. i know how measurement and numbers work

The issue with your drawing conversions has to do with how drawing programs deal with measurements. They are based in an abstract way as "units" and those units are set in preferences and displayed accordingly. They typically aren't converted and need to be re-scaled by a size ratio and simply not by changing the units in many cases.

As for the US not adopting the metric system, it had more to do with the associated costs more than anyone not being able to understand it.]]> vegasloki General Thu, 26 Feb 2015 01:35:23 -0500 https://reprap.org/forum/read.php?1,475880,475964#msg-475964 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475964#msg-475964 tmorris9 General Thu, 26 Feb 2015 01:08:51 -0500 https://reprap.org/forum/read.php?1,475880,475954#msg-475954 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475954#msg-475954 elwood127 General Thu, 26 Feb 2015 00:04:08 -0500 https://reprap.org/forum/read.php?1,475880,475945#msg-475945 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475945#msg-475945
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KingRahl
Metric is a base 10 system. Easy to calculate. Most of the time you read inches as a fraction. While you can reinvent the wheel just to suit your needs it won't be practical. You'll have to remember we are using a low level computer that has to do a lot of calculations on the fly as it is (changing coordinates into steps per cm) If you throw fractions into the mix, that's just something else to go wrong.

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pushthatbolder
...I have tried importing using imperial and it makes the object 2.5 times bigger...

This is because there are 2.54 cm in 1 inch. The file was exported using a 1/1 scale.


Yes i know that. I was just stating it to support my post.. i know how measurement and numbers work]]> pushthatbolder General Wed, 25 Feb 2015 22:33:04 -0500 https://reprap.org/forum/read.php?1,475880,475944#msg-475944 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475944#msg-475944 IMBoring25 General Wed, 25 Feb 2015 22:25:55 -0500 https://reprap.org/forum/read.php?1,475880,475928#msg-475928 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475928#msg-475928
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pushthatbolder
...I have tried importing using imperial and it makes the object 2.5 times bigger...

This is because there are 2.54 cm in 1 inch. The file was exported using a 1/1 scale.]]> KingRahl General Wed, 25 Feb 2015 21:21:04 -0500 https://reprap.org/forum/read.php?1,475880,475922#msg-475922 Re: Why Metric? https://reprap.org/forum/read.php?1,475880,475922#msg-475922 I have tried importing using imperial and it makes the object 2.5 times bigger. Not good

I never liked having to think about a 64th of something, let oline an inch. I could not fathom the thought.
I can metric is easy. Microns, mm, cm, km and these value cubed, are their Litre Counterpart.

Metric is the world standard.
Was even supposed to be in america. But not all americans could not grasp it.
My mother in the 60s and 70s said they only had a few lessons in metric then it was all to hard to implement in all the schools

in sketchup you can design in inches. And export in MM, that may be there only to facilitate the imperials.

Try to measure a micron with a fraction of an inch, now say it five times fast...]]> pushthatbolder General Wed, 25 Feb 2015 20:54:31 -0500