robin.parker wrote:From past experience and disappointments (despite making use of very capable professional help) with ancient and oily ally castings, I'm inclined to agree with Dai, if you can find a way to affect a repair without welding that's the best approach.
This is what I was afraid of. I would prefer to use TIG but I don't have a set and though I could go out and buy one this is not a job I want to learn on.
I have stick and MIG and have been welding (as an amateur) for 40 years. I have books on the subject and check up on the techniques before tackling something new. I know about pre-heating alloy (to the point where sawdust 'sparkles' when sprinkled onto the surface
My worry was distortion. I was thinking that I would have to bolt both halves of the cases together or else bolt the half case to a strong flat surface before heating and welding. Is this an issue I should worry about ?
I am rather reluctant to go to 'experts' as so many prove to be less expert than they claim and I'll only have one shot at this.
I have a lathe and repair stuff without welding where I can.
The kickstart shaft sleeve on the SA gearbox was broken in three places - due to the bronze bush in the kickstart sleeve being worn.
I set the end cover up on my faceplate and machined the sleeve off. I then threaded the hole.
Next I turned-up a new, threaded sleeve.
The new sleeve fits fine. I still have to finish-off the inside and drill the holes for the kickstart spring to locate in but its almost there. I also turned up a new bronze bush for the shaft and pressed it in.
This sounds easy but in practice it took me a few days. The one thing I could have done better was to cut reverse threads - but I'll peg the sleeve to the case to prevent it from coming loose under the action of the kickstart. The spring will also locate it.
On later Sturmey Archer boxes this sleeve was replaceable, so this isn't a new problem
As a wise man once said "having a lathe does not make you a Machinist" - I have learned a lot
Thanks for all the comments folks. I'll have to make a decision sometime soon as I want the bike to be on the road in 2015.
My avatar shows the late Len Rich in 1970 with the bike I now have - a 1958 Ariel VH