LH Fork Slider - Drum Brake

... you could fit a stud instead of the bolt (which would be a sounder engineering approach anyway). 5/16 UNC one end, CEI at the other.

try RGM i got one for a dominator and a commando

At first I assumed the bolt actually screwed into the fork bottom but if it's a plain unthreaded 5/16" hole for a nut & bolt then yes, tap to 3/8" BSW and make a stepped stud would be the wayI would go. Although there isn't a huge amount of surplus material down there......

Hi both Ian's,

I speak as owner of 1964 fork legs. Fitted on an Electra but as Dominator of the time.

At that time the pinch was with a stud with nut. No washer listed under the nut, but I use both a plain and a spring washer. Threads were 5/16ins cycle at each end of stud.

Remain confused as to part number of my fork leg but think 19299. I've seen 06.0351/64 and 030031. 

I'm sure someone will confirm the thread on your early (date?) Commando fork leg, but very much doubt if there were Commando fork legs with BSW tapped holes for pinch stud. The UK move generally in early 70's was towards the American UNF and UNC threads with A/F spanner sizes. Driven by directives from government in the 50's and 60's when the Commando, Mini, and Nato fighting vehicles were on the drawing boards.

As Ian S says, when secured into aluminium, a stud and nut is a much better solution than a bolt. 

Peter

Attached photos show my replacement early Commando LHS Slider. Purchased from A/N about 5 years ago. I was expecting the pinch mechanism to be threaded for a stud (as for Dommie) but instead it was a clean hole with an AF threaded bolt as the clamping device. 

Works fine but you do need 2 spanners to undo the bolt. There appears to be enough metal to cut a thread for a stud or larger bolt if somebody wants to do do..

... I use a spring type and only tighten till it's flattened, as I do with carb nuts. I'm not really sure what advantage there is to having the LHS spindle gripped tightly anyway as the nut on the RHS clamps the whole assembly up firmly. It seems to me that allowing the LHS to float slightly might help with keeping the forks aligned but am not brave enough to slacken off the pinch bolt entirely......

You pump the forks to get the correct alignment with the bolt loose, then tightening the bolt keeps the alignment. Even modern forks work that way albeit with twin bolts and enough alloy thickness so they do not break if a Gorilla gets to tighten.

I have a commando slider - I think its pinch bolt side, ill have a look tomorrow

dan

I found my slider which I think is NOS - but it has a bolt not a stud. 

I believe the available Commando slider is interchangeable with the earlier version,

A lot more meat around the pinch bolt on later sliders, making them Gorilla proof?

I have several old versions in service that have been welded up. If done properly no issue.

The earlier P B sliders tended to have studs. My two Commando sliders used bolts.

I read that use of a suitably narrow fibre washer in the gap can prevent over tightening/ fracture of the leg.

A lot of years ago in my youth I rode a Norton with this arrangement. Somewhere/somehow the alloy leg stud assembly broke the alloy (must have been a bit 'enthusiastic' with the spanners!) I don't remember any embarrassing moments! I seem to remember finding the break after a time!

The hole in the wheel spindle is of course very handy to hold the spindle still when fitting/unfitting but again I have never used this hole for such, The spindle always seems to be an easy fit and tighten with its nut. Provided the brake and wheel are correctly fitted of course.

... Al's experience bears out my view that clamping the spindle is unnecessary. The fork leg on my ES2 has been repaired by a previous owner and seems to have been done quite well but I'm very reluctant to put too much force on it.

Just remember it is only a pinch bolt and doesn't require much tightening.

I should have mentioned the fiber washers for use with the earlier slider PB. They certainly do help to prevent over tightening.  But all the same, go easy with the spanner. The PB is only to stop the spindle from moving. 

I think it was said above, to push down on the forks several times before nipping up gently the PB to centralise the forks.

The amount of cc in each leg and the weight of oil is another interesting fork topic. But down to rider preference in this case. ('The hole truth')