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Units of Different Industries and Shops “Survey”


Jul 25, 2021
Lots of internal debate here on whether we should transition our whole shop over to the metric system. Lots of pros and cons to each. So, I’m generally curious:

1) What Industry do you work in?

2) What percentage of your parts or prints come in as metric vs inch?

3) How do you handle this in your shop? (converting or not converting prints, working with both unit systems, inspection, machines setup, fixture design, etc.)

M.B. Naegle

Feb 7, 2011
Conroe, TX USA
1. Machine Manufacturing. Specifically machines for the Leather industry.
2. 50/50. We sell and service stuff from Europe (all metric) as well as manufacture our own lines, many of which go back to the turn of the century so they are not only standard, but often have odd bastard threads and such.
3. We default to Standard unless it is a part of an all metric assembly/machine. Most of our own machines and tools are standard, as is the raw stock we get. IMO it's not a hassle or problem. Our prints for metric parts will typically have both metric and standard equivalent dimensions posted, and most DRO's, digital measuring tools, and CNC controls can toggle between them as needed. You have different tools for different jobs and different dimensions for different parts. Neither system is superior (yes I said it). Each works and has easy points and complicated points.

IMO the push to go "all metric" is naïve and a total waste of resources. It's a sore topic for me because so many of the "go metric" proponents seem to have their mind made up that America is just being consciously stubborn and that's the only reason we haven't pushed the magical Metric button yet. If someone came along and told me I HAD to switch NOW for whatever serious reason, it would be a major fiasco that could potentially shut our business down because now we're replacing all our perfectly functional tools and constantly converting dimensions so we can make parts to fit 150 years worth of machines out in the field. That's our business. Not all of it, but enough of it that there is no good reason to screw those customers over just so we can mime some ethereal hyped up image of a perfect worlds measuring system. If things keep going as they are, eventually Metric will take over and I'm ok with that, but I see no benefit to jumping ahead in that process.


Jan 14, 2007
Flushing/Flint, Michigan
1) I make carbide, cbn, pcd inserts. CNMG, TPG, SNAA, etc.. You know what these are.
2) Now where it gets strange.... Almost all metric inserts are made to inch standards so the numbers on the box are not quite right.
This good in that most of my gauging and machines work in inch. Tips that you buy for cbn,pcd are almost always metric even it they come from the guys in Ohio.
3) When we do get a metric special we dual dimension everything.

Most of my customers have gone metric on their parts made. This make it confusing when an engineer tells you he/she is off by point zero two.
If said is out 20 microns I know what this means but still have to do the conversion in my head since I still think in inches.

If you have to provide SPC size control data with parts make sure it is in the system or print type of numbers designed.

The bigger problem I see is training the worker bees. Two systems in place confuses them so fast.
It is messy and one should be able to work in or understand both but that may be asking a lot of those on the floor.
Here I'd like to know what Ox does as he must hit this problem everyday on most runs.

Seen job shops do the switch.... think one-two years before it becomes the culture and understood.
Maybe some thought as to what system your machines run? Size adjustments, tool offsets and all that in which?
Gonna change all these easily?
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Hot Rolled
May 13, 2015
1) Aerospace

2) 100% inch

3) Every once in awhile we get something that is obviously been converted wrong, or has metric units, but its generally fairly obvious.


Sep 23, 2013
1) Spindles. Rebuilding, manufacturing, grinding, and making associated parts.
2) Any print we make is metric, incoming rfq prints we see are about 50/50.
3) We work in metric, think in metric, and anything that is inch we typically complain and convert. When it comes to spindles anything made past the 80s is overall metric, so it just ends up being natural. We certainly see some here and there that are inch, but typically old hydrostatic wheel heads or something of that sort. Plus the tolerancing we need to hit is inside of a tenth, yet millionths get confusing, microns are so much easier.

We do have some customers that send in grinding work and tolerance only in inch(on metric sizes..), just adds more variables when doing conversions to use metric gauging.


Dec 14, 2017
1) aerospace, safety
2) 99% inch
3) convert to inch

50+ year old argument here. In middle school they really pounded our asses full of the change. It was coming! Get ready! NOT!

At least for dimensional measurements in the machine shop it really makes no difference to me. Simple conversion and lots of drawings are dual dimensioned anyway.

The imperial system is goofy for other stuff. Recipes and dry vs liquid ounces, for example. I'm not sure the authors always know the difference.

Really, if you tried to create a system sillier than imperial you'd have to try pretty hard!


Mar 15, 2004
Edison Washington USA
I work in one country thats inch, and one thats metric. So I can estimate sizes by eye in both, (for stuff over an inch) and have tools and measuring tools for both. You adapt.

One interesting thing- almost every country uses inch measurements for plumbing pipes and fittings, especially for water supply. Most of the world uses BSP- British Standard. Some places, like the USA, use NPT- which is a tapered thread. The same size BSP to NPT usually leaks, unless you use various local tricks- I have used sisal thread and goop, teflon tape, or even epoxies, if adapters are not easily available.
But food service equipment, and brewery stuff, is mostly metric. But japanese metric plumbing parts dont necessarily interchange with german, especially for brewery plumbing- a buddy does a ton of that kind of work, and one of his special super powers is knowing whats inch, asian metric, and euro metric, and knowing where to get the parts to connect them. Especially with microbreweries, of which there are close to 400 in my state, you find a mishmash of Euro, Asian, and US used equipment, and making it all play nice together is a very specific skillset.