Reply To: Howard 350 petrol cock stuck on.

[davidbliss]

They often keep to same BSP thread pitch for pipe fittings, however if you have a gauge it saves guessing. if its of US manufacture they use NPT thats only one thread per inch different, I get the odd motor cycle they often used cycle rate 26 tpi for there oil fittings thats not good into alloy being so fine. I often make my own taps and dies and a easy metal to machine then harden is EN24 works quite well as can go up a few thou without going up to next size. I recently was repairing a 1924 French car gearbox that was very poorly designed that allowed a non captive bearing to work partly off, as there is a French odd ball metric pitch I did that at a imperial 1/2”size to be equally awkward.