A topic for Glenn or Harold re: metrics

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NP317
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Re: A topic for Glenn or Harold re: metrics

Post by NP317 »

I am most familiar with the "English" system of measurements, and aside from digital measurement tools I have an "SAE" shop.
However... As an Engineer I appreciate the overall simplicity of the unified Metric system and prefer it in general.
I have taught myself to visualize metric unit distances, which makes it far more useful overall.

But there are always exceptions, because of history.
While working on a 1910 ten-ton (US...!) steam traction engine, we have recently determined that the t-bolts holding the steam chest cover in place are Whitworth threads, while the rest of the engine is SAE hardware!
So here we go again.
RussN
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Harold_V
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Re: A topic for Glenn or Harold re: metrics

Post by Harold_V »

I, for one, would welcome a copy. I'll send you my email address.

Mean time, speaking as one who is in the situation of which you speak, the harsh reality is that those who don't understand our units of measure are highly unlikely to understand any other. Metric is easy for those who have an interest, but is a foreign language to those who do not, just as the "inferial" system is. Some folks simply don't care. A football field as a reference makes enough sense to them that they are satisfied. In my opinion, only the curious care enough to explore. These things make little difference in the life of the average person. They're often too busy worrying about their hair color than such matters. But I certainly could be wrong! :wink:
Thanks for the article, Marv.

H
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Bill Shields
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Re: A topic for Glenn or Harold re: metrics

Post by Bill Shields »

then there are those of us who, while our machines may have DROs -> the leadscrews are all imperial -> and running metric threads problematic since my machines are not 'dual unit' gearboxes'

so while I may work with Metric in my $$, job, my home hobbies pretty much remain Imperial since I am well past the stage in my life when I feel the need to replace a basement full of lathes just so I can cut metric threads to follow a specific design.

I like Kozo's work...but not enough that I feel the need make the investment to 'build it metric'.

2,5", 3.5", 4.75 and 7-1/4" gauge is just fine for me.
Too many things going on to bother listing them.
rrnut-2
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Re: A topic for Glenn or Harold re: metrics

Post by rrnut-2 »

I built a machine last year for a customer that was going to Germany. The only part that wasn't metric, was the air plumbing. Building it in metric wasn't hard with the DRO's on the mill and lathe as they did the conversion for me. The most expensive part of the machine was the CE certification.

I am now sorting all of my hardware, metric in one drawer, imperial in another drawer. The interesting part is that I have more metric hardware than imperial hardware. But I still think in imperial and draw in Solidworks in imperial.

Jim B
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tornitore45
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Re: A topic for Glenn or Harold re: metrics

Post by tornitore45 »

Talking about sorting to keep tooling straight...
All my wrenches, socket, Allen wrenches, nut drivers etc get a flash of paint is selected areas. GREEN for metric RED for SAE
I have a few metric TeeNuts, they get a green coat as well

Even the few drill rod stock I have in metric gets a spritz of Green
Mauro Gaetano
in Austin TX
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liveaboard
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Re: A topic for Glenn or Harold re: metrics

Post by liveaboard »

People sure do get emotional about this subject...

I don't get it with the lathe lead screws; mine is (inexplicably) imperial and I cut lots of metric threads. And it's a cheap old lathe, way below what most of you are using.

I have almost no imperial tools now. Or hardware.

When it comes to trans-Atlantic trade, there's a lot more involved. Voltage obviously, motor mounts and spare part availability, and as Jim said, certification is required for most things.

Some things appear the same at first glance, but are not.
Like straight euro pipe threads (HUH??) and posidrive cross slot screws.

I have some imperial micrometers. free to anyone who'll pay the postage, I honestly have no use for them.
rrnut-2
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Re: A topic for Glenn or Harold re: metrics

Post by rrnut-2 »

liveaboard wrote: Tue Nov 30, 2021 11:20 am Like straight euro pipe threads (HUH??) and posidrive cross slot screws.
Now I know why the customer specified american pipe threads! I never got an explanation from them.

Jim B
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Harold_V
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Re: A topic for Glenn or Harold re: metrics

Post by Harold_V »

For those of you who have built melting furnaces and procured commercial refractories, maybe you've wondered about the odd packaging. I am one of those people.

Last night I did a quick search for instructions for mixing Greenlite 45, an insulating refractory that I'm going to use for the primary lining of the melting furnace I'm building (it will accommodate a #30 crucible). The instructions for the Harbeson-Walker refractory (it's the old A.P. Green material) was designated in metric units. That's when the light came on. Instructions were for 1 kg (220 pounds). A 55 pound bag is ¼ kg.
Like it or not, we are (slowly) moving towards the metric system. The question in my mind is, how far will it go? I'm likely way too old to live long enough to see how it shakes out, but I have my doubts that it will ever be 100%. I suspect that some of the things we do in the imperial system will remain, simply because they work just fine, and may even be superior (Jim's experience with pipe threads is a good example). In fact, some units (like degrees F) are finer, and provide a closer graduation between individual units.

Could be wrong, of course!

H
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Harold_V
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Re: A topic for Glenn or Harold re: metrics

Post by Harold_V »

liveaboard wrote: Tue Nov 30, 2021 11:20 am I don't get it with the lathe lead screws; mine is (inexplicably) imperial and I cut lots of metric threads. And it's a cheap old lathe, way below what most of you are using.
How?
Not that I don't think it can be done. It can. Fact is, my Graziano is equipped to do just that. Trouble is, unless you have the proper conversion, the lead of any given thread won't be correct. Yes, it will usually be close, but if you have a long enough engagement of screw and nut, it won't work (unless both are generated on the same machine, at which time the same error is applied to both members). Tap a deep nut and single point the mating component and this will come in to clear focus.

So, what do you do when you have a long engagement?

H
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tornitore45
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Re: A topic for Glenn or Harold re: metrics

Post by tornitore45 »

120/127 gear fixes everything. Cross-slide and compound dials is another story. Convert the major diameter to Inches or mm whichever is the case and use the mike of the same breed as the lead screw.
Mauro Gaetano
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Harold_V
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Re: A topic for Glenn or Harold re: metrics

Post by Harold_V »

I'm aware of the 120/127 gearing, but he hasn't made mention of that. That's why I am curious.

H
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Bill Shields
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Re: A topic for Glenn or Harold re: metrics

Post by Bill Shields »

And with the 127/120 gearing ..does the thread dial still work -> or are you limited to power off and reverse instead of half but disengagement?
Too many things going on to bother listing them.
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