Union nuts & cones?

[gwrdriver]

Greg and all,
Many years ago MSC offered a bewildering array of very reasonably priced "special" taps and dies which included 40-TPI. I began to buy a few, thinking this would be a good way to economically acquire 40TPI "ME" taps and dies, but what I quickly realized was that these US 60° thread form tools wouldn't successfully mate with the 55° thread form of the British ME series.

The thread angle wasn't the problem. I found there would be a fouling at the roots and crest caused by the difference in thread forms, the British threads having rounded root and crest, and the US not. The result was that a fitting could only be run in with fingers about 2 turns before stopping and required force after that. And of course as we all know, if we have to force a mechanism something isn't right. Running a US tap or die over an ME fitting eliminated the fouling.

Of course if you make your own fittings and stick with a single there's no problem, but prospective buyers of Victor's taps and dies (and I'll probably be one) should be aware that they will probably be US thread form and won't be a no-mods match for fittings made with British ME threads.

[Greg_Lewis]

Thanks for the heads-up, gwrdriver. Wouldn't it be nice if the whole world was on one single thread system?

[tornitore45]

Victor Machinery is a gem. Fair prices and large assortment.

[dnevil]

Dianne,

Here is a short article with drawings for making Union nuts and fittings by Billy Van Brocklin.

http://ibls.org/mediawiki/index.php?tit ... 6_Fittings

Regards,
Daris