Gibson crankpins

[Horsetan]

Whilst I know that there is a difference between M1 and 14BA I have intermixed them on occasion with no problem, at least on crankpins. My most common use is an Ultrascale flush crankpin nut on a front axle behind slidebars, and many times these crankpins are AG.

Nowadays you wouldn't have to worry about a mismatch, since Ultrascale changed over a while ago to supplying M1 screws and nuts for crankpins.

[Philip Hall]

Not so sure about that, since my most recent batch are 14BA. May be down to the availability of 14BA at times?

Philip

[Enigma]

I am currently working on a chassis for a small Barclay and have turned up some threaded crankpin bushes, needed especially for the front wheels to avoid a clash between them and the back of the crosshead. I have tapped them (into a 0.8mm hole) with a 14BA tap that I have had for years and they screw onto the Gibson screws with no problem. In the past I have also used the same tap to fit Gibson crank pins (bought from Alan) into homemade brass wheel centres, although it is a few years since I last did this so the screw specification may possibly have changed in the meantime?