Axle nut tightness on new ascot

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Marcel
Posts: 3
Joined: Fri Jul 03, 2020 1:16 pm

Axle nut tightness on new ascot

Post by Marcel » Sat Jul 04, 2020 10:18 am

Hello all, after fitting new hub seals to a 1937 Ascot, I tightened them up as much as I dare but now I cannot see the holes to fit the split pin. I've been offered all sorts of advice from filing the back of the nut to slacking the nut off then tightening up to the nearest hole, but what is the definitive answer?

Rod
Posts: 15
Joined: Sun Nov 24, 2019 9:44 am

Re: Axle nut tightness on new ascot

Post by Rod » Mon Jul 06, 2020 3:37 am

I understand the ATDC recommendation for hub nut torques is 100-150 lb/ft depending on the application.
If you're sure you are tightening the nuts to their spec and the split pin holes don't line up it is sometimes worth trying another nut [or swapping the nut from the other side] before you do anything permanent to the nuts you have. If you are going to face off the back of a nut to align the slots in the nut with the hole in the axle, it is vital to keep the back face of the nut square to the bore of the nut, so care is needed. My experience with this arrangement is you usually don't have to machine all that much off and you can make a reasonable approximation how much needs to come off by comparing the fraction of a turn needed for alignment of the slot and hole with the pitch of the thread. A good aid is to scribe a radial line across the end of the axle in line with the split pin hole as a guide. It is far too easy to consistently take too much off the back of the nut and thereby have the hole always missing the slots in the nut...
Edit: using a spacing washer under the nut would also be another non-invasive method, this is the same as making the nut or the hub 'longer'. I would suggest a hardened washer would be best if you're going with this way.

bob_allison
Posts: 110
Joined: Wed Nov 27, 2019 3:20 pm

Re: Axle nut tightness on new ascot

Post by bob_allison » Mon Jul 06, 2020 10:24 am

To keep things nice and square , and in default of machining , you could rub down the back of the nut on emery on a hard flat surface . Wet and dry and paraffin works well , and keep turning the nut in your fingers so as to do the job evenly .You will get tired of the job before you take too much off .

peter_christie
Posts: 29
Joined: Wed Nov 20, 2019 3:46 pm
Location: Newton Mearns, Glasgow

Re: Axle nut tightness on new ascot

Post by peter_christie » Mon Jul 06, 2020 11:25 am

Hi Marcel,
The advice of our technical guru, Tony Mealing, is quite clear. If you refer to pages 31 & 32 of his (ATDC Publication) Guide to Owning, Running and Maintaining an Austin Light Twelve, you will see that he says "The hub nut has to be done up really tight, say 150 ft/lbs and you may need to use a spacing washer to ensure the split pin fits."
From my own personal experience this is good advice. If the hub is in any way loose on the taper at the end of the half shaft then you are heading for a broken half shaft. That once happened to me on a 1936 Ford V8, the right hand rear wheel overtook me and the mechanic at the Ford agent in Penrith showed me the signs of movement on the taper. The sheared end of the half shaft looked just like the business end of an Austin starting handle!
Best of luck,
Peter C. [6515]

Marcel
Posts: 3
Joined: Fri Jul 03, 2020 1:16 pm

Re: Axle nut tightness on new ascot

Post by Marcel » Tue Jul 07, 2020 7:16 am

Thanks to all who replied. Using a combination of your advice, I swapped the nuts over and was able to tighten and secure one side, while a little judicious filing on the other saw a new split pin home and dry on the other. They might be tighter than 150lb but they're not likely to come loose. Thanks again, Marc

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