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Dimensions. Metric or standard? tooling, machines.

huleo

Hot Rolled
Joined
Feb 12, 2014
Location
UT
We have been discussing of we need to make changes in the shop as we seem to be constantly converting between metric and US std. I think it mostly has to do with the our machines and tooling. For instance, some vices are std, some are metric. Yes, you can "make it work", but also nice to have a firm std to work from in the shop. All our machines are Jap so metric, yet we run them in inches and use lots of metric tooling.

I am not looking for a novel, just curious if anyone has found a solution? It seems like the old Chevy problems. Is it a 1/2" or 13mm? Hell, I don't know. I don't even think GM does!


Since it would seem the USA is about the only ones stuck in "inch land", I would be curious what part of the world you are! I know it makes a difference. I go to the hardware store and get to pay double for metric bolts! WTF!
 
FWIW, I am in the UK and work pretty much exclusively in metric. We get some imperial prints, and our common method is to model the part in inches, then switch to metric in cam.

Our most prolific source of imperial drawings is actually from a very large Italian company, who had a division in Houston for many years, that did most of their drawings. That division was shut down a few years ago, for reasons that I am unaware of, and they are gradually remodelling all of their legacy parts and creating metric prints of them.
 
We are a large corp, but we are exclusively metric. There is the odd-ball machine here and there that were been bought over the years before the purchasing standards were put in place that use imperial fasteners but everything else is metric.
 
So as far as tooling goes, I guess if you guys are using metric vises or imperial? How about the T slots on the table? I think almost all HMCs are metric? But is that true on VMCs? Rotaries?

I think the most annoying thing to have a vise that is imperial but have a metric table to put it on so nothing fits right, but so close.....

I had to deal with this on the lathes that are certainly metric but bushings are all over the map. Metric OD but imperial ID....WTF!!!!

To make it more fun, we commonly reach for metric cutters in mills for features that first day engineers designed like a .25" radius..... Thanks!
 
All of our machining centres have metric t slots. There are a couple of different sizes, but that's because we have a pretty wide range of sizes of machine. Our oldest machine still in service is a 1991/2 that uses the same t slots at the same pitch as our much newer machines, so fixtures are interchangeable.

Our rotaries are all metric, mounting diameters and fasteners.

As for lathes - if your turrets are metric, just buy metric tooling. Typical US made boring bars/drills are imperial shank so that's why you have mixed bushings.

Vices are a bit different as just about every vice model has unique dimensions. No simple answer there.
 
So as far as tooling goes, I guess if you guys are using metric vises or imperial? How about the T slots on the table? I think almost all HMCs are metric? But is that true on VMCs? Rotaries?

I think the most annoying thing to have a vise that is imperial but have a metric table to put it on so nothing fits right, but so close.....

I had to deal with this on the lathes that are certainly metric but bushings are all over the map. Metric OD but imperial ID....WTF!!!!

To make it more fun, we commonly reach for metric cutters in mills for features that first day engineers designed like a .25" radius..... Thanks!

Huh? I don't get it, is the table tapped with a grid pattern with no T slots or something? Don't see what the table has to do with it... even then if something doesn't fit (for whatever reason) make a subplate...?
 
We have been discussing of we need to make changes in the shop as we seem to be constantly converting between metric and US std. I think it mostly has to do with the our machines and tooling. For instance, some vices are std, some are metric. Yes, you can "make it work", but also nice to have a firm std to work from in the shop. All our machines are Jap so metric, yet we run them in inches and use lots of metric tooling.

I am not looking for a novel, just curious if anyone has found a solution? It seems like the old Chevy problems. Is it a 1/2" or 13mm? Hell, I don't know. I don't even think GM does!


Since it would seem the USA is about the only ones stuck in "inch land", I would be curious what part of the world you are! I know it makes a difference. I go to the hardware store and get to pay double for metric bolts! WTF!

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most cnc you can G20 or G21 easily enough BUT tool comp is normally inch on many cnc so you run cnc in G20 or inch mode. also grid shift and other parameters like maximum rapid feed often are in mm not a problem just have to be aware when changing
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not a problem ALL tooling is off perfect size and gets measured not only for tool size but also runout. i got a tape measure in inch/mm and i got a caliper in inch/mm so never had a problem. optical tool presetter dont care. measuring bores zeroed to a ring gage so dont matter there either.
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drawings we tell computer what we want and it will make a inch converted drawing in seconds. not a problem. all parts are in metric but dont care cause i use inch drawing and inch measuring tools. never been a problem
 
To make it more fun, we commonly reach for metric cutters in mills for features that first day engineers designed like a .25" radius..... Thanks!

So how is it the engineers fault ?

YOU reached for the Metric cutter....

Did you provide feedback to said engineer "No inch radii allowed" ?
 
I always use metric. If needed, I convert inches to metric, but never metric to inches.

But I'm European. Even after living 10 years in the US, I'm still having problems visualizing what is 3/16". LOL.
 
I always use metric. If needed, I convert inches to metric, but never metric to inches.

But I'm European. Even after living 10 years in the US, I'm still having problems visualizing what is 3/16". LOL.

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get yourself a inch/mm tape measure. its saved many a conversion error from happening. many places give them out for free as tape measure cheaper than messing up a part. same with digital caliper. just press of a button and its either inch or mm. what ever you want
 
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most cnc you can G20 or G21 easily enough BUT tool comp is normally inch on many cnc so you run cnc in G20 or inch mode. also grid shift and other parameters like maximum rapid feed often are in mm not a problem just have to be aware when changing
.
not a problem ALL tooling is off perfect size and gets measured not only for tool size but also runout. i got a tape measure in inch/mm and i got a caliper in inch/mm so never had a problem. optical tool presetter dont care. measuring bores zeroed to a ring gage so dont matter there either.
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drawings we tell computer what we want and it will make a inch converted drawing in seconds. not a problem. all parts are in metric but dont care cause i use inch drawing and inch measuring tools. never been a problem

gotta remember the GRID SHIFT!! :D:willy_nilly:
 
gotta remember the GRID SHIFT!! :D:willy_nilly:

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grid shift and maximum rapids and many parameters are in mm or millionths of a meter. not a problem, on grid shift check list is a +1 increment equals -.00004" or similar so can quickly figure direction and amount change.
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anytime maintenance repair work done and i usually check grid shift before tight tolerance jobs. it reduces scrap and rework problems.
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on a horizontal cnc there is grid shift AND center of index (rotary table) calibration
 
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get yourself a inch/mm tape measure. its saved many a conversion error from happening. many places give them out for free as tape measure cheaper than messing up a part. same with digital caliper. just press of a button and its either inch or mm. what ever you want

Random reading from a digital caliper: 11.52 mm.

After pressing in/mm buttom: 0.4535"

0.4535" x 25.4 = 11.5189 mm.

Of course, I don't work with that type of tolerances, but it just bother so much, that it's the reason I don't convert from inches to mm.
 
Random reading from a digital caliper: 11.52 mm.

After pressing in/mm buttom: 0.4535"

0.4535" x 25.4 = 11.5189 mm.

Of course, I don't work with that type of tolerances, but it just bother so much, that it's the reason I don't convert from inches to mm.

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i dont use inch/metric taper measure or digital caliper to .0001" tolerances its only to see if i am in the ballpark
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woman lost her hair and it was found she had selenium poisoning. her vitamin pills were suppose to have selenium added in micrograms NOT milligrams , she was getting 1000 times more selenium and was being poisoned.
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that what i look for the big errors. mason doing basement wall measuring opp corners diagonally sees its exactly same reading but later finds its exactly 1 foot off. too busy looking at inches and not the feet. hard to describe same as using 1 foot 1" and it ends up 11" that type of big error is more of a problem
 
Random reading from a digital caliper: 11.52 mm.

After pressing in/mm buttom: 0.4535"

0.4535" x 25.4 = 11.5189 mm.

Of course, I don't work with that type of tolerances, but it just bother so much, that it's the reason I don't convert from inches to mm.

Why does that bother you? Do you think the caliper is accurate to .001mm?
 
We have been discussing of we need to make changes in the shop as we seem to be constantly converting between metric and US std. I think it mostly has to do with the our machines and tooling.


huleo,

I think the key is having all the measuring tools in metric: micrometers, gage blocks, pin gages, indicators, etc. I have not switched over yet primarily because I haven't dropped the $ yet for all the metric measuring tools.

I do get a fair number of drawings in metric though that have obviously been designed in inches, then just converted at the end (which can be a bit irritating at times, LOL).

PM
 
I used to work in a metric shop... for no other reason than the boss thought the imperial system was stupid. We had only domestic customers that bought our products, and many of our competitors were imperial. It was a constant irritant to our customers that our prints and parts were in metric. The competition is still in business...

I actually liked using the metric system once I got used to it. I can still easily visualize metric dimensions like 6.35mm and 12.7mm... heck I can even visualize big numbers like 25.4mm.
 
I would work in metric if I could. The Speedio clearly wants to run everything metric, and the scale of my parts is clearly more suited to metric dimensions than inch. The troubles I have are that tooling options in metric are pretty thin as far as inventory goes, in small quantities, and all your stock is going to be in inch. Can you work around that? Sure! But I guarantee you'll have more fuck-ups and fat finger problems working with imperial tools/stock in a metric world than you will the 4 times a year you need to delve into machine params and speak a Japanese mill's native units.

In the meantime, I just throw absurd anti-Metric memes at people, mostly as a succor to my internal frustration that I haven't just bitten the bullet and converted myself over to it yet:

7OhfJ5y.jpg
 








 
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