The coarse thread gauge is 1/4 - 20".

The fine thread version is 1/4 -28".

There are some Ludwig vintage wingscrews with larger thread gauge but for the foot pedals, stands, and hi-hat clutches the two listed above are most commonly used through the Chicago vintage production period.

I don't have any but thought this info might assist you in finding some here.

Thanks for the info!

If I am correct, the coarse were used for tripod leg spreads (on all stands), the top of the tripod section on all stands (except early Atlas cymbal stands with the dog ear collar), cymbal tilters (flat base-solid rod), and at the top of the middle sections on the non-flat base cymbal stands (like early Atlas).

Also, if I am correct, the fine were used for the Speed King beater adjustment, hi-hat clutches and at the top of the middle sections of flat base cymbal stands (that accept the solid rod).

Am I missing anything?

Its my understanding that also the coarse ones were used on the middle tube at top on the flat base cymbal stand's that had the "L" shape piece that hold the solid rod..Also the thin ones were used on the bass drum leg mounts 70's on the wing spur's....Mikey