Hi LJ,
Its a problem isnt it! all i can say its a Bloody good job Her in doors doesnt actually find out how much i have spent on what she calls "Rusty old boxes of Crap" .... im mortally wounded by her comments! I think its because i promised her a day out and took her to Kempton Park bike jumble, not my smartest move.
As you probably know im gathering the parts to rebuild my RR, Im buying a bit here and a bit there, peed off that the dam swinging arm will either have to be changed
or i will have to Mod the original to take the QD hub (Torque arm and Chainguard) Other threads here talking about replacing SW bushes put me right off! (funny enough its a job i have never had to do).
Anyhow this Nut is on the wish list! Nearly every primary case i have seen has marks from this castellated nut coming loose. As you say the crank is pulled up and shimmed onto the drive side by the nut and tension of the Cush drive. As you rightly said this has to be done up Bloody tight (about 4 and a half white knuckles i think) which is a pain to do with a castellated nut theres probably a "Tool" for the job, i could make one i guess. But the SRM one looks nice and they do make nice parts (at a price) by the look of the one on my engine it looks like its been done up with a cold chisel.
SRM and Burton Bike bits and quite a few others sell on ebay now.
Cheers
Steve