Dynamo Woe

[terryg]

Is there enough thread on the armature end to get two thin nuts on, in a locking arrangement?
I haven't got the bits in front of me but I'd be inclined to look at that possibility, together with a suitably thinned version of Dutch's peg spanner.

[trevinoz]

Trouble is, Terry, the thread is 15mm, 18 tpi. It becomes a lot of work for something which is not necessary.
Don't even think about using Loctite on the lock ring either because when it needs to be removed usually flame is involved.

[terryg]

Thanks Trev. Is that a PG9 thread?
PG = Panzer Gewinde.

If it is then taps are a bit pricy, I agree.

[morris]

I tighten the nut by hand and give it a couple of knocks with a small aluminium drift. Did several like that and never got one to come off.

[trevinoz]

Terry, I don't know whether the thread is a PG or not but I suspect it is just a Lucas special.
They did the same on voltage regulator adjusters and Altette push rods, seemingly a thread for a task.