We need to make about 250 special nuts for a specific application at work.
As an exercise, we've decided to use a punch and die to flange the hole into
mild steel sheet, .04-.06" thick.
I need to know the correct ID for the hole before roll tapping. I'm sure it
can be calculated (Cliff) but I don't have time and I need to get the design
Thanks for any help.
I understand that small deviations in diameter can have a very significant
effect on the thread. By a bit under, something like 5.4? Perhaps 5.45 (inch
Thanks for your response.
.213" or a number 3 drill will put you smack in the middle of the pitch
diameter for a 6H thread. BTW, you didn't mention the pitch. M6x1 is what
we're talking about here, right? 5H or 6H tolerance? What percentage of
thread do you need?
Sorry about that. It has been my experience when talking metric threads, it
is assumed coarse unless the pitch is specifically stated (certain sizes
have more than three fine pitches).
I'n not really sure. This isn't a *really* critical issue. The reason I
wanted confirmation on the hole diameter is because I will have to grind a
punch and I'm too lazy (efficient) to do it twice.
The nut will be used to attach light structural members together (the Bosch
framing version of 80/20 extruded aluminium.) More thread would be better
for strength, but I don't think our design will have a great issue with
Thanks for the suggestion.
I've often wondered if calling out a thread as an M6 alone is a standard
way of calling for a coarse pitch thread. I see that on metric drawings a
lot. You would think it would say M6 ISO Coarse or M6x1 just to be sure.
Thanks. Like I said, I've often wondered about that. I've always taken it
to mean a coarse thread, but every time I do, there's a nagging little
doubt in my mind as to whether or not I'm doing the right thing. Good info
on the class of the thread too. BTW, I hate metric prints. I don't mind
working in metric at all, in fact if anything it's easier. But the drawings
Metric is (mostly) all I use (I'm in NZ), and the only dealing I have with
"imperial" prints it when I have to convert to metric. Our machines &
measuring equipment are all metric, I'ts all we know :-) This country
metricated long ago, it's a far better system IMO.
If we woke up in the morning and gremlins had swapped all our prints to
metric, it would be fine. It is the conversion that is the mess. All our
machines and dros are one button away from metric, hell, half the people
use digital calipers.
Now the US is like a 40 year old virgin, you can try to talk her into
it, but the odds are slim....
The metric system is horrible for construction and manufacturing. The Inch
or Imperial system is far more managable. First off the scale is an
inconvenient size. Second industry for the most part "grew up" around the
inch system. Many of the standards for things like class of fit,
tolerancing, and size in general were developed around the Imperial system.
Quite often I find that when I'm converting a metric print to inches, the
multi digit metric numbers convert neatly into standard "inch" sizes. The
resolution is also off for manufacturing. .001 mm or 1 micron is too small
to be practical. There are no .001 micron resolution conventional
micrometers because the scale is too small to read. Even most digital
micrometers have a disply resolution of one micron, but the accuracy and
repeatability of them is several times that.
Here is a good explanation of some of the disadvantages:
So that's a good argument in favour of teaching me a system which has no
relationship or continuity?
What does that mean? Imperial shaft-hole classes aren't *round* numbers and
neither are metric classes. The major difference is that the metric
shaft-hole fit system can be extrapolated using a simple chart. For
instance, if you know the spec for an H7 and an L9, you can easily figure
out an L7, H9, l7, h9, l9, and h7 without a calculator (of a similar nominal
size of course).
Perhaps talk to the engineer? I build heavy stamping dies for OEMs from
Europe and NA and they are built in metric (using round metric numbers) and
I build tools and tooling for my European apprenticeship (designed in
Germany) and they use round metric numbers... Not really an issue with the
metric system (or imperial system).
And .01mm is less than half a thou. I don't believe imperial micrometers are
produced in .0005 increments (no vernier scale)?
At the push of a button they read to .00005". Can they be expected to be
accurate to 50 millionths?
A cube has a volume of ten gallons (you pick the nationality). What are the
side lenghts in yards (no calculator or reference text)?
A cube has a volume of ten liters. What are the side lengths in meters (can
probably be done in one's head)?
Because I have been trained on both, I am comfortable machining parts using
either unit. Given a choice, I would take metric because the mental math is
It means that the imperial system evolved along with man. It is based on
unit sizes of familiarity. Ever hear of a foot? What do you suppose that
As a matter of fact it is. The other day the quill handle broke on our
Taiwanese knee mill. Turns out to be a 3/8" thread. Same as on the U.S.
made drill press which has three handles. So we borrowed one until the
replacement arrives. What is the IC size of a CNMG431 insert? And on and
on. Industry grew up with a system that grew up with mankind. The inch
system of lengths has realationships, fairly easy ones that relate to
everyday life. As far as continuity, the Imperial system beats the metric
system hands down. Man has been counting by twos since he learned to
count. The computer you're using is based on the very fast and efficient
binary system. Thank god the French haven't insisted on applying the
metric system to computers. Computers manipulate strings of ones and
zeros in groups of four, eight, sixteen, thrty-two, etc.. The foot has
been used as a unit of measure by every race on the planet. How many
times have you seen someone measure a roon or space by pacing it off heel
to toe? The division by twelve is also quite ancient. It comes from
counting the knuckles on of your fingers on one hand. Did you ever notice
in history the number twelve appears often? 12 tribes, twelve gods, etc..
It was natural for the foot to be divided by twelve, and easily divided
by 1/2, 1/3, 1/4, 1/8, and so on, all easily visible by looking at your
hand. Conversley, the metric system of the meter is based on a mistaken
calculation of the diameter of the earth, and a division system of tens.
Not very user friendly. All over Europe people have improvised systems to
help them relate the scale of the metric system to every day life. So you
end up with people using a system of two metric "feet", divided up into
24 pieces to end up with metric "inches" of a 25mm length. Stupid.
You're not quite getting what I'm saying, and I'm having trouble figuring
out how to put it together in a better way. Read through Machiery's
Handbook and I think you'll get it.
I started out much the same way, except in a U.S. based apprenticeship.
As I recall the die heights, mountings, die bed dimensions, were all
inch. Has that changed? What about a company with a twenty year old
Minster? That press would be built all in the Imperial system.
Useless information in your every day life. Why would you ever need to
know the length of a side of a ten gallon cube in yards? I do know that a
gallon is 231 cubic inches off the top of my head, so you'll have to
trust me that I can take the math from there without a calculator. I also
know that most people don't need to know that info so they don't bother
to learn or remember it. Not everyone needs to be able to design a
coolant tank, and those that do have managed just fine for at least a
dozen millenia (there's that damn number twelve again). Proponents for
metrication always seem to posit these silly arguments. Where would I be
or what would have happened to the world that I couldn't figure out your
problem? The metric system falls apart in real world situations. Let's
say you get up in the morning and want to make coffee. It takes 3/4 cup
to make a pot. The measuring cup has gone missing. No problem, a handful
is equal to a 1/4 cup. 3 handfuls and I'm done.
How's that? In most manufacturing measurement is carried out in a system
where the inch is divided by tens, same as metric. However if I need to
cut a plate to 7' 3-3/8" it's a real simple proposition to take a
measuring tape and mark the plate. That equates to 2219.33 mm. How hard
is that to keep straight in your head and measure on a Metric measuring
Well, I could see your point if all our feet were the same (I imagine shoes
would be significantly cheaper as well).
Our Taiwanese machines are built with metric fasteners. That argument is a
I have no idea. I would buy the insert by it's designation, not its IC. What
does that matter?
Which industry? Go to Germany and see how many imperial fasteners you find.
They don't count?
I find that .0001" relates to nothing in *everyday* life, and why should it?
What is the OD of a #12 thread (no calculator, no paper, no reference)? What
about a #00?
My mind is nimble enough to think in meters without having to remove my
Dial in 65/128" on a DRO for me.
What does binary counting have to do with manufacturing? You're grasping at
Who cares? I have a tape measure and I know how to use it.
No, I haven't.
I was under the impression that the metric system is based on some
wavelength of light through a vacuum. Meaning one can create a metric length
standard anywhere in the universe.
I've never seen that. You're right, it is stupid.
It looks like you haven't convinced anyone here.
Read through the European equivilent to that book and you'll get it.
I am doing my Canadian apprenticeship simultaniously. It is both metric and
Yes. We build our dies in metric. Name and OEM...
Our old Hitachi press uses metric, as well as our British Clearing presses.
The shut height readouts are typically digital anyway.
True, but steel is purchased by weight, which means volume.
Well, if you don't have an application to know the side lengths of a ten
gallon cube in yards, I guess the metric system is not for you.
Whoa! Watch the *s* word.
What the hell does that have to do with the metric system? Are your hands a
So you should have no problem with either.
Is that scribble 73-3/8" or 7'3-3/8"?
Talk about not connecting...
The fact is that I can work easily in both. You're used to the imperial
system so you don't want to change. Forget logic...
Have you ever used metric for any length of time?
It doesn't matter to me either. You were the one who disagreed that many
industrial standards were developed in the Imperial system. I don't
suppose you have any mills that take CAT tooling, or drill presses with
Morse tapers, or knee mills with R8 spindles, or lathes with 5C collet
All of the plumbing for one.. Have you ever left your home town?
I know these dimensions off the top of my head. I've probably been in
manufacturing longer than you've been alive. I don't think I need to pass
any tests that you are giving. I find this question ironic coming from a
guy who didn't know the pitch diameter of a metric fastener and got the
size from me. Even more so that you have to use a standard Imperial size
drill to get the hole size you need.
But you find fractions difficult?
12.889mm No problem.
Fractions are convenient. BTW, where can I buy 80mm floppies?
Sorry, I just don't have it in me. So let me ask you a question.
The United States built the largest economy in the world, remains the
largest manufacturer, is the largest exporter, as well as the largest
market for the rest of the world's goods. How will converting to metric
benefit this country?
We have the best of both worlds here in my opinion. We live in a dual use
society where both Imperial and Metric are common. The benefit to the
Imperial system is that it's built on a human scale and it's easy to
visualize and approximate. The benefit to metric is the continuity
between units of measure, which is useful in science, medicine, and some
industries. As far as metalworking goes, what's the diff? It's all just
numbers in a program or on a digital gage anymore. All of the imported
CNC machines we sell take Imperial size tool shanks, people don't want to
pay the cost of tooling up a machine that is not compatible with that
which they already own. All of the manual machines are Imperial
throughout, fasteners and all. The market governs what people are willing
to pay for these machines, the builder in the "metric" country is the one
who has to decide if they can build an "inch" compatible machine and
compete with the native builders. Seems that quite a few can. I heard
that Haas just sold their 50,000th machine. Many of those were exported.
Seems that they can figure out how to work in both systems as well.
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