On 12/7/2016 12:33 PM, Scott Dorsey wrote:
Leon Schneider wrote:
Scott Dorsey wrote on 6 Dec 2016 16:45:21 -0500:

Assuming "Imperial" means "USA", that would mean I need a 32 TPI nut
somewhere between 0.271 inches and 0.305 inches in iD, but that doesn't
seem to be a standard size for a USA nut.

Sure isn't, that's deliberate.

I keep seeing this *mix* of metric and what they seem to call "Imperial",
(which I guess is the USA?).

Are we really that imperial?

No, Imperial measures are not the same as US measures. An Imperial pint is
0.57 litres, while a US liquid pint is 0.47 litres.

US measures, Imperial measures, and English measures are all different.

So they mix letters, percents, millimeters, and inches but each one
designates a different measurement.

That's how it goes. I've seen pressure gauges in pounds/cm2, even. We
live in that kind of world.

Aren't these two different measurements measuring the same thing?
1. Metric: 7.7 mm OD, 6.9 mm thread root, 0.794 mm pitch
2. USA: 0.305 in OD, 0.271 in thread root, 32 TPI pitch

Right?
That means it's *not* a mix.

It depends how the original document specifies it. But you could think about
it either way if you were setting a lathe up.

My question is:
Isn't the tire valve NOT a mix of measurement standards?

I don't know, I haven't read the original specification document. It's
likely written in terms of ordinary US standards, given when and where it
came about.

It's not a standard SAE thread, but then there are an infinite number of
possible threads and only a very few of them are standard SAE threads.
--scott


Right and Schrader (1890-ish) predates SAE anyway. Prior
standards were UNC/UNF, before that NC/NF and before that
Whitworth 55 degree threads in an era when many
manufacturers of many things made up thread formats as they
went along.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971