Page 1 of 1

Swinging arm spindle nuts.

Posted: Tue Aug 26, 2014 11:27 am
by jj.palmer
Hi, NH 350 cc 1954.
Arrived home the other day after a ride out and discovered that one of the swinging arm spindle nuts, the large chromed and domed nuts, was missing which left the swinging arm assembly loose on its bearings, the bearings are of the phosphor bronze type and not the rubber. I can only assume that the nut had loosened through vibration and had fallen off, luckily the centre spindle had stayed in place due I believe to the pulling power through the rear chain.

The thought of what could have happened is rather frightening.

Has any one experienced this situation before and if so have they devised a method of positively locking the nuts to avoid them vibrating loose ie a mechanical method of locking rather than something like Loctite, I intent to ensure that it will not happen again.

Regards
John Palmer.

Re: Swinging arm spindle nuts.

Posted: Tue Aug 26, 2014 3:16 pm
by steve.clarke
Hello John
Not a problem i have seen before, but as the nut is convex and the seat is concave you can't us a lock washer so the only engineering solution is to drill and pin not an easy job to line that up and no room for tightening, i have always used thread locker on that sort of application with no problems as long as the item you are locking is clean and dry, when you tighten the spindle nuts get someone to sit on the bike off the main stand that sets them in the right place for securing.
Cheers Steve.

Posted: Tue Aug 26, 2014 9:55 pm
by robjameson
I think the original metal-elastic bushes push back against the nuts locking them, I'm guessing with phosphor bronze there is little or no resistance and could be the source of the problem.

Posted: Wed Aug 27, 2014 9:49 am
by keith.hodgenia
I've got something like this.
http://www.ebay.co.uk/itm/Warrior-Motor ... 20e1d0d406
They don't fall off again. Keith.

Re: Swinging arm spindle nuts.

Posted: Wed Aug 27, 2014 9:56 am
by david.anderson
When you replace the swing arm rubber bushes with bronze bushes, the bronze bush cannot run on the original spindle. A hollow tube must be made up. The hollow tube should be the combined length of the steel centres to the original rubber bushes plus the spacer between bushes. The original spindle is inserted through the spacer tube and the swing arm bushes run on the spacer tube. The spindle nuts can then be tightened as original and never come lose.
The spacer tube should be made from 4140 steel or similar and it should be hardened. Case hardening is adequate. Mild steel will wear rapidly. The underside of the swing arm should be drilled, tapped and fitted with grease nipples (preferably extended grease nipples) and the bushes should be regularly greased.
Alternately the outer face of the bronze bush can be machined and fitted with O rings at the outer diameter. The swing arm bearing tube is drilled and plugged somewhere at an accessible central location so that it can be filled with oil. The bushes then have a long lasting supply of lubricant.
A properly maintained bronze bush swing arm takes all the flex out of the rear end and improves handling.
David
IMG_2077.JPG

Re: Swinging arm spindle nuts.

Posted: Thu Aug 28, 2014 10:32 am
by jj.palmer
Hi,
Thanks for your replies and advice, at the moment I am awaiting the delivery of the replacement nut from Drags, I will get started as soon has it arrives and let you know the outcome.
David, your description of the phosphor bronze type bearing is exactly as fitted to this bike, it was fitted by someone previous to myself. I assumed that at one time you could buy a kit containing all the parts.

Regards
John Palmer

Re: Swinging arm spindle nuts.

Posted: Thu Sep 04, 2014 9:42 pm
by jj.palmer
Hi
Have just finished making and fitting mechanical locking to the swinging arm spindle nuts, see photo's, I now feel much safer when riding.

Regards
John Palmer

Re: Swinging arm spindle nuts.

Posted: Thu Sep 04, 2014 10:00 pm
by jj.palmer
Hi
Just another photo showing the 3 components, the other photo's did not show to much because of the reflection from the stainless steel and the chrome.
Regards
John.