The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: Johannes on 26.08. 2013 21:03

Title: BSA B31, front wheel spindle
Post by: Johannes on 26.08. 2013 21:03

Hello,

My name is Johannes and I am a new member of this amazing forum. I started to restore a B31 from 1953 and I have a problem!
The thread in the sliding tube of the fork is slightly damaged and has to recuted. I measured the size of the front wheel spindle but it is not so easy. I believe it is a 9/16-20LH thread. I looked for a tap a figured out it is common for bicycle pedals. I borrow a tap from a bicycle dealer. However, the tap started to clamp after 2 rotations and I stopped. Now I am not sure whether it is due to the condition of the thread or the size is wrong.
I would appreciate if somebody can tell me the right size.

Regards
Johannes

Title: Re: BSA B31, front wheel spindle
Post by: a10 gf on 26.08. 2013 22:46

Hello, and welcome to the forum. You may get some help here for your B, but this is 99,5% an A7A10 place, and we'll be there to help when you buy yourself a twin!

Title: Re: BSA B31, front wheel spindle
Post by: muskrat on 26.08. 2013 23:47

G'day Johannes.
That size sounds right. Check the tpi of the tap against the axle thread. It may have been butchered long before you got it.
Cheers

Title: Re: BSA B31, front wheel spindle
Post by: bsa-bill on 27.08. 2013 10:24

yep cycle is 26tpi up to and including 7/16,then goes to 20tpi but 7/16 can be both

Title: Re: BSA B31, front wheel spindle
Post by: terryk on 27.08. 2013 13:52

Heres a helpful thread chart in PDF format so you can download it


http://www.gerardsgarage.com/supportfiles/Threading_Tables.pdf