On Sun, 27 May 2012 09:45:16 +0100, Justin C
wrote:


I've never heard of such a thing, what a marvellous idea.

What an interesting post. I had to identify an unknown thread last
week and hadn't heard of these either. In my case, I measured the
width of the bolt and tried to match it against tables I found from
googling "screw thread". I think I may have used results from
wikipedia because it was a web site I had heard of, unlike the other
search results.

The gauge seems to add a layer of complexity because you have to
measure the thread pitch and then look at a table to translate that to
diameter though. What's wrong with my method of measuring just the
diameter with a vernier calliper or micrometer? I suppose one flaw
might be that just measuring the diameter would not tell you whether
it was a 55 degree or 60 degree thread. Are there other flaws?

It seemed to work at the time to identify a 3/16" unc for me but I
might buy a gauge for next time. Thanks.