Many thanks for posting that. I see what you mean.
You are right ... I've checked ... the 3 grubs are on the inner ring with the numbers on. The outer, knurled edge, part has the 1 grub. Mine still has thread but it's not holding.
Maybe I could get that drilled and threaded at another 2 points and then there are 3 grubs holding the outside.
That inner ring can come off all together. It's there so you can set the distance on focus by loosening those 3 grubs and turning it until the numbers line up with your focus. It's not used at all so I could remove that and have a bush made up that fits over the solid unit and the outer bit. Grubs can hold that in place and the custom wheel goes on the outside of the bush. In fact the outer screw on part can go as well and just make a new cover that sits over the sidewheel area and has a closed end.
Still relying on grubs though so they may work loose.
Good luck with yours.
I suppose the grubs on the new bush could be slightly bigger and be Allen head so a drop of blue threadlock could be used as the grubs should be able to be removed with an Allen key.
Last edited by skires; 15th February 2014 at 08:30 AM.