burman thread size

[chaz]

I know not drectly BSA but does anyone know the size of thread on the  mainshaft of a Burman gearbox
clutch end, its 5/8 guessing 20tpi but what BSF,BSW?
actually on a Ariel Huntmaster
also is it acceptable/wise to get a damaged thread welded and re cut?

[Goldy]

I don,t know about Burman gearboxes, but 5/8 BSF is 14 tpi, BSW 11 tpi. I would think it.s BSC which can be 20 or 26 tpi.

[bonny]

I know not drectly BSA but does anyone know the size of thread on the  mainshaft of a Burman gearbox
clutch end, its 5/8 guessing 20tpi but what BSF,BSW?
actually on a Ariel Huntmaster
also is it acceptable/wise to get a damaged thread welded and re cut?

if you weld it you might (read will) bend the shaft with heat distortion , better to turn it down to the next smallest size or replace it , have you tried draganfly ?

[dpaddock]

If you metal-spray it, the temperatures involved are too low to warp anything.
Alternatively, you could probably recut the thread to 9/16 CEI and still have a good grip if it's not a tapered shaft.

David

[groily]

It's 5/8 20 for sure. BSC I'd say for the lack of other matches. Problem with turning down is that the clutch push-rod on the Burman is quite a chunky thing and there isn't that much metal to play with if you clean right down to the minor diameter to start again. No chance of getting it back with a die and a new nut?
Faced with the same problem a year or so back, I cleaned things up as best I could, cut the thread just a tad deeper in the lathe and made a new nut a fraction under-size. Hell of a palaver but works fine.
Good luck!

[chaz]

tried thread file to clean out, and thread pitch gauges but as half thread is missing thought best to ask.
currently using a new nut with loctite but looking at a strip down as found a spare shaft.

what I would like for a project bike is a mainshaft for a square four which I believe is around 3/32" longer than a
standard burman shaft.