Hi all- I am very much a beginner- I purchased a Kennedy box with some stuff in in quite some time ago- one of the things in it was what looks to be a wire with a precision ground triangle attached to both ends- in this case measuring .245 point to flat. I think I saw Abom, in one of his videos use a similar tool to measure threads with a mic. I am assuming to measure the minor diameter. Can anyone tell me what this is called, and how to use it? I don't see these in any of the tool catalogs. Thanks!