@mwhjohnson @ai6yr Any "real" hardware store should have some brand or another in stock; Taskar, US General, etc. Lots of companies still make them. Hardware suppliers like McMaster Carr sell versions with actual bolts and nuts rather than just plastic threads too. Hard to imagine life without one, or at least a thread pitch gauge.
Edit: Turns out the nicer ones with metal parts are all the rage; Amazon and Temu have hundreds to choose from. Not that I like buying from either.
@W6KME @mwhjohnson See, someone needed to tell me this 20 years ago, the amount of time I have driven to the hardware store only to buy the wrong thing, or spent 30 minutes trying to figure out what to buy with no idea of the size, or even just spending time in my workshop trying to figure out what goes with what... well worth the whole $7 I spent.
I also recommend buying a cheap big box brand digital micrometer that can display metric, fractional ANSI, and decimal ANSI. Sometimes the gauge card isn’t fine enough, and it also saves running back and forth to the tool box with a pocket full of sockets and box wrenches.