American machine screw types

You need to try to find a copy of this handy little book:

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Michael A. Terrell
Central Florida

OK. The most common size is 6-32. 8-32 and 10-32 are also common. This is AWG size 6, 8 and 10 all with 32 tpi threads.

Also 10-24 and 12-24 with 24 tpi are used.

See

for more.

Sounds like 6-32 and 4-40.

BA.

But are they what we call UNC ? and the 40TPI ones ? only measured with a ruler as my thread gauge, in inches, does not have 40TPI and the mm gauges are not close to any equivalent.

See the chart on the web page.

Also

Now wait a sec. If you're comparing AWG size with screw sizes as above ? I think you have your wires crossed!.. #6 wire is larger than #10 wire.. 6-32 is smaller than 10-32 screws.

just an observation I made once long ago.

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Years ago, I worked for an American computer equipment company, and used to have exactly the same problem with not being able to equate the screws fitted to the enclosures, to anything available in the UK. I won myself a right royal bollocking from the UK director of engineering, after I had been speaking on the phone to one of the design enginering staff in the U.S. I had phoned him to ask if we could get a stock of the case screws sent over to us. "Sure" he said. "I guess I could arrange that. What size are the ones you want ?" "Oh" said I, "about three sixteenths APF". "APF ?" said he. "What's APF ?" "Why, American Piss Fit of course !"

Well, I *was* new to the game and only young. I didn't know much about America and the good people who live there, and just assumed that our humour was the same. Didn't do anything like it again though ...

Arfa

Which wire guage?

Correct. In fact see

for the 24111 Tri-Tap Tool, which taps 6, 8 or 10 size holes at 32 tpi.

Only nation on earth still not using metric, no?

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they

to

been

ones

humour

Perhaps APF screws in aeronautics This flight would have flown over me , not that I would have been aware that the pilot was hanging out of the cockpit.

"The subsequent inquiry revealed that the windscreen had been replaced just

24 hours before the flight, and a number of errors in the procedure resulted in the wrong size bolts being used to fit the new window. Although the difference in size was minimal, some 200th of an inch, it was enough to cause the windscreen to blow out when the pressure differential became too great between the cabin and outside atmosphere."

At least when I'm hunting for the 1% or less of "American" screws in my pile of salvaged mm and BA screws the coarse pitch makes them stand out in comparison. I still don't know if its safe to go out and get a pack of 6-32 and 4-40 UNC machine screws for American equipment, where someone has been there before and not replaced all.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

We're fairly used to UNF and UNC in the UK as they were much used on cars before metric came in - but only really in the larger sizes. For small stuff Lucas ;-) stuck to BA.

But I still see AF and AC taps and dies around - are the two versions still used? I realise there's not a vast difference - only basically thread profile.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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It should have gone without saying. But let me turn that on its head:

While the rest of the world clings pathetically to the idea of forcing a single tyrannical system on everyone, Americans have freely embraced the idea of duality. We have plenty of legacy equipment that still works perfectly well and needs support, and when making new we can choose whatever fits best. There are a few "clingers", but most of us just saw the metric system as additional options to use at will, not as a mandatory replacement. Mechanics have tools for both systems and not only switch freely between them, but take extra advantage from the wider range. A couple examples: a 12mm wrench will probably work on that 1/2" bolt head that's partly rusted away; a 1/4" bolt will probably fit that 6mm hole you just stripped out.

The bottom line: not only are Americans now fully fluent with metric and decimal measurements, but we are also still fluent with fractions and SAE, *and also* familiar with conversions and inter-relationships between the systems. We have the best of both worlds and then some.

American Fine and American Course.

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    Dave Plowman        dave@davenoise.co.uk           London SW
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You are describing a 6-32 screw. Probably NC. (UNC) This is a very common screw used in the USA. Hope this helps. Jim

Say what? Most Americans of the US variety wouldn't know a metre from a kilogram.

"Homer J Simpson" wrote in message news:JYY7i.71289$g63.25753@edtnps82...

Unfortunately, it's not confined to the U.S. Our kids in the UK are all the same now also. Can't do any math without a calculator. If you ask if they know their eight times table, they will say " 8 - 16 - 24 - 32 " and so on. All well and good, but if you say to them " so what is five times eight ?" they will say " 8 - 16 - 24 .... " only now they will add in counting on their fingers until they get to 5 ... I see pieces in the local newspaper written by new reporters, and have a hard time of making any sense of anything they have written. They all speak with some dreadful accent that they have learnt from watching Australian soaps, where the last syllable of any sentence ends on an up-accent as though they are asking a question. The few that don't do this, do the exact opposite, which makes them sound like profoundly deaf people do when they speak. I went to a Grammar School, and had what I thought was a pretty reasonable education. I came out of there perhaps a little more literate and numerate than some of my friends who went to schools which had a slightly lower academic standard, but I did not consider myself anything other than at the top end of average. I certainly wasn't Oxford or Cambridge material, and I knew many other kids who were whole realms above me. But when my own kids went to school, and we started to get into the homework help thing, and when they got interested in TV quiz shows, and I was able to answer most of the questions without hesitation, I gained a whole new respect from them. My two daughters who are now 20 and

22, still refer to me as a genius. Now I find it really sad that as things should be improving, they are actually declining, and what I considered to be an average intelligence, is now looked upon as genius. I wonder how they would refer to someone who genuinely is that clever ? So it's not just a U.S. thing.

Arfa

Hey, just yesterday I drove almost 40 kilograms to by a meter of sugar.

I started off with Whitworth, and later BA. Then we went to metric.

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I'd have thought BSW 'equivalents' to the smaller BA sizes rather rare?

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    Dave Plowman        dave@davenoise.co.uk           London SW
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