In article ,
"N Cook" wrote:

Homer J Simpson wrote in message
news:nJE7i.68874$g63.47216@edtnps82...

"N Cook" wrote in message
...

For period 1970 to 2000, whatever they are, they are not very common in
Europe. Coarser thread , diam for diam, than the usual European mm and
BA.
Common sizes are about 0.132 in outside diam. , pitch 32 TPI, would they
be
UNC 6 ? and 0.11 inch od and TPI about 40 , would they be 4 UNC ?

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 http://www.zytrax.com/tech/mech/threads.htm for more.






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.

UNC is a coarse thread. UNF is a fine thread. UNEF is an extra fine
thread. 2-56, 4-40, 6-32, 8-32, and 10-32 are common, but many others
are prevalent as well, including the "odd" numbers, e.g. 3-48.

It's worth noting that 6-32 is a UNC thread while 10-32 is a UNF thread.
The "fine" version of a #6 screw is 40 TPI; the "coarse" version of a
#10 is 24 TPI.

And of course, it goes without saying that the obstinacy of my fellow
Americans, clinging absurdly to a ridiculously clumsy system of
measurement, is pathetic.