Commando gearbox inner cover nuts

Have you tried 1/4 whitworth? If you dont have whitworth sockets and spanners stop now until you do!

Hi Jan

I haven’t done that job yet so don’t know for sure, but that size could be 1/4 Whitworth. A good set of Whitworth spanner’s and sockets is worth having for a Commando. 

cheers

Steve

1/4"whit Is a nominal 13.34mm across flats, so as Gino suggests it may be worth investing in a few sockets or box spanners.

Cycle part wise  you should be ok with AF sockets and spanners, but as a Dominator owner I have no idea what was updated inside the motor and gearbox when the Commando came into being.

Good luck!

... Whitworth spanners - 3/16" BSW / 1/4" BSF, 1/4" BSW / 5/16" BSF and 5/16" BSW / 3/8" BSF will cater for most things. If you get slim 3/8" drive as discussed in another thread they will do you fine.

The Commando gearbox essentially dates back to pre-war days so many of the components have BSF. Whit and Cycle threads.

are these 5/16 BSC 

use a box spanner as very close to edge and a socket may not fit

rgm sell reduced nuts which make the job much easier RGM part number E3231

Definitely 1/4" Whitworth / 5/16" BSF (exactly the same size - the hexes were all brought down one step during WW2 to save on material).

I just bought a Sealey 3/8" drive set on eBay 181570393880 £14.77 which fits on those nuts just fine. 1/2" drive might not.

Steve

Hi I buy a lot of stiff from RGM but didn't know about the reduced size nuts (and I've just rebuilt my box!

Definitely worth the money since there is very little clearance on one of the nuts.

By the way, everything on the gearbox appears to e  cycle thread / whitworth!

One thing I discovered that is not in the manual; it helps if the gear change cam is in the neutral position when fitting the selectors!!

Good luck,

Keith

... about those nuts but you can get 5/16" Cycle nuts with reduced hexagons from Nookys Nuts and others. They're used on BSA A10 magnetos if I remember correctly but I find them very handy for monobloc carb studs which have very limited clearance. It also helps to not overtighten them.

There is no need to use reduced hex nuts on the MK3, as above the 3/8 drive 1/4 Whit slim wall sockets can easily be found these days.

The reduced hex nuts are OK for the older covers which had a small diameter spot face.