Hi Hans...Here is some information on your previous gearbox query...

There are three different types of pegs for the gear selector fork shafts...(and a roller)

The 1940 illustrated parts list (which is the same as earlier ones in this respect) shows part no.66-3239 for the peg...In conjunction with this peg type a roller is also used..part no. 66-3238. I believe these parts fit into the 'wide' pattern track in the fork but don't have an example to confirm this.

This set up was replaced by part number 66-3258 for the peg...This was used without a roller and ran in the 'narrow' pattern track in the fork...
This is shown, for example, in the 42/43 parts list for Contract S1048..

This was changed again with the introduction of the post war type heavy gearbox to part number 66-3291 for the peg...This was also used without the roller but had a head size that utilised the 'wide' pattern track in the fork..

Increasing the pegs head diameter and the radii of the bends in the fork track gave a smoother action and less resistance to changes in direction due to the 'gentler' bend....
This last type can be found, for example, in the 49-55 parts lists for both M and B Series types...Ian

email (option): ian@wright52.plus.com

Thanks Ian, that's what - I admit - forgot

email (option): viaconsu [at] planet'dot'nl