Quote Originally Posted by mklotz View Post
It's plastic so you'll want to be a bit gentle with it. I don't use the plastic threads to identify an unknown screw. Instead I find the one with the nearest diameter to the unknown, remove it from the board and use its nut to test the unknown. That way only the screws that actually fit the threads in the board are screwed into it and the chance of damaging the plastic threads is minimized.

I look at it as just a very compact way of organizing a test screw collection. I have these...

https://www.amazon.com/Bolt-Thread-C...s%2C152&sr=8-4

as well, purchased earlier, but they must be taken off that infernal cable and mounted to a board to make them useful and, when that is done, the result is way bigger and heavier than the little plastic thread gauge.
I have a thread checker in plastic that was under $10, but not really satisfactory. It has samples of the threads protruding from the surface of the checker, too far frm the edges except for the larger screws, and holes with thread OD, but not threaded. Not too useful. Has fastener length gauges for metric and imperial fasteners, too, that are useful, but overall, not very satisfactory. I went through the first 10 pages of thread checkers that came up on Amazon and didn't find anything like it. Got it from the local tool wholesale place, Steve's Wholesale tools for $3 or 4, so out a terrible amount on money on it. I do have a pretty fair collection of metric and imperial hardware, and a 4-84 leaf-type thread checker and similar one for metric threads, so I can identify the correct screws for the upgrade. If I had bought the good stuff 40 years ago, it would have been much better than faking it as I have all these years, but I didn't know then what I know now. And wasn't smart enough to realize it.

Bill