The disc sander on my Draper belt & disc sander has been slipping. I thought
that this was the belt sander but tightening the belt had no affect. I then
realised that the disc itself was slipping on its shaft.There is an
inspection hole in the belt guard and I can see a socket headed grub screw
but my allen keys are too short to reach.
Screwfix mention long allen keys in their catalogue but how long is a long
allen key?

Thanks

Kevin