The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Gearbox, Clutch, Primary => Topic started by: BSA500 on 31.07. 2014 13:34

Title: Cured gearbox sprocket nut coming undone
Post by: BSA500 on 31.07. 2014 13:34

Hi,
I have always had a problem with the gearbox sprocket nut coming undone-well no more. As you know its a 'ring nut' with cut outs for a c spanner. Put it on use a c spanner(or a drift and huge copper mallet my favourite) and tab over the washer. That was the problem because as we know that tab washer has no real tabs so sooner rather than later it comes undone. Thread lock useless. Well I had a moment of great revelation, I have an angle grinder so I ground two flats onto the ring and viola a large area to tab over. If this has already been written about it doesn't hurt to remind people who hadn't seen that post(me included)

Title: Re: Cured gearbox sprocket nut coming undone
Post by: Topdad on 31.07. 2014 14:11

Nice idea ,I'll do that on one I'm working on now cheers, BobH

Title: Re: Cured gearbox sprocket nut coming undone
Post by: chaterlea25 on 01.08. 2014 23:42

Hi
The normal method is to prise the lockwasher into the slots in the nut  *????*
A  "C" spanner is no good
I made up a steel tube with two ears at the end to fit the slots and a nut welded to the outer end

Properly cleaned metal and loctite will work

John

Title: Re: Cured gearbox sprocket nut coming undone
Post by: BSA500 on 02.08. 2014 11:14

So does a big idiot grinder and its far easier to knock over a large portion of the tab :) . Besides I love my grinder :)

Title: Re: Cured gearbox sprocket nut coming undone
Post by: Briz on 02.08. 2014 20:05

I rather like the look of SRMs big hex nut with the oilseal in it.
Something you can properly tighten down with a big socket and a leak-point eliminated.

Title: Re: Cured gearbox sprocket nut coming undone
Post by: BSA500 on 03.08. 2014 18:51

Yep that would be nice  *smile* pity about the price(tight me)  :!

Title: Re: Cured gearbox sprocket nut coming undone
Post by: madsens on 04.08. 2014 09:24

Hi
I bought one of the SRM hex ones, when putting my A-10 together.

But it simply wouldn't fit - no way I could get it to go on the tread - so I had to reuse the old nut, that went on with no problem...

Wrote SRM about it, and we agreed to return it and I got a full refund.

A mate had made up an old socket with 4 wings that fit the old C-spanner nut, worked well.

regards
Joergen

Title: Re: Cured gearbox sprocket nut coming undone
Post by: morris on 04.08. 2014 22:45

Quote from: madsens on 04.08. 2014 09:24

But it simply wouldn't fit - no way I could get it to go on the tread - so I had to reuse the old nut, that went on with no problem...

Had the same issue with a regular cush drive nut I recently bought from my usual supplier. Had to run a 3/4 X 20TPI tap through it to make it fit.