Half. Time nuts

Stanley Chappell

Well Known and Active Forum User
VOC Member
is lt correct to fit two thin nuts locked tougher on the main shaft to secure the half time pinion on my A comet or a single nut and centre
Pop as on post war engines if two nuts. Are locked tougher is there need to centre pop.The forum ha s gone very quite is every one
Gone into hibernation
 

delboy

Well Known and Active Forum User
VOC Member
is lt correct to fit two thin nuts locked tougher on the main shaft to secure the half time pinion on my A comet or a single nut and centre
Pop as on post war engines if two nuts. Are locked tougher is there need to centre pop.The forum ha s gone very quite is every one
Gone into hibernation
Hi Stan,
I'll reply whilst I'm in "A" mode and still awake.
If you look at page 391 of "Back to A" you'll see the 1937 parts list shows 2 x E80.
Quite how you hold the inner one whilst tightening the outer?
Anyhow, personally I would fit one nut, give a miss to the centre popping and use a small amount of "Nutlock". Perfectly satisfactory and much kinder to the threads.
Cheers, Delboy.
 

billirwinnz

Well Known and Active Forum User
VOC Member
Hi Stan
I had the nut come undone twice on my TTR despite the use of nutlock. Unlike some other designs that use a LH thread once it loosens it undoes with the inertia of the shaft rotation. The cause was the key which was a neat fit in the shaft but a loose fit in the pinion. It was able to fret and worked the nut loose. I made up a new stepped key and used a wider nut from a BSA crankpin with plenty of high strength loctite. It will need heat if it is to be removed in future but it hasn't loosened yet.
Cheers Bill
 

greg brillus

Well Known and Active Forum User
VOC Member
The 2 nut method works fine, but as Bill pointed out, only if all the parts are a neat fit. Do the first nut up tight and then the second up tight against the first.......Remembering they are only a thin nut so excessive torque will destroy the nut........loctites are great, but use the 2 nuts in preference to this, as the shaft thread is long enough to accommodate doing so.
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
Stanley my handsome, the E80's on "A's" are of a larger hexagon size to post war so I put a 2 BA thread into a corner of the nut. Fit & tighten nut then get the tapping drill and put a de-tent into the half time pinion, might have to start with a smaller carbide drill.
 

delboy

Well Known and Active Forum User
VOC Member
Stanley my handsome, the E80's on "A's" are of a larger hexagon size to post war so I put a 2 BA thread into a corner of the nut. Fit & tighten nut then get the tapping drill and put a de-tent into the half time pinion, might have to start with a smaller carbide drill.
Stanley,
go right ahead and fit both E80 nuts as God and PEI intended. Both chaps knew a thing or two.
Personally, If I was still apprehensive, I would still use a drop of the correct grade of "Loctite" on the outer nut rather than bashing or modifying.
Cheers, Delboy.
 
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