There is a 3/4" threaded sleeve and nut that holds the rear brake drum and sprocket to the fork end. Does any one know what the thread profile should be.
My nut is very rounded off and rusty and need replacing. The thread is however strange and appears to be 24 tpi. The nut is most definitely 24 tpi but I am worried it should be 26 tpi. The sleeve thread is a little distorted and I am concerned a 24 tpi UNS nut may have been forced on. (UNS is a non standard thread available in many TPI ranges but was not introduced until the 1950's)
Can anyone help please
Bob Southall
What year and model is the machine?
1929 model 8
3/4" 24 Tpi it is on both my bikes. 1929 and 1932.. part no 754 listed for quite a few models..same thread as the brake cam spindle boss..i ordered a 3/4" 24 Tpi whitform tap from tracy tools to make new nuts.
There doesn't seem to be a standard thread in 3/4" x 24, which is why i went for 55 degree Whitform. John
Hi Bob,
BS811, Cycle Threads, includes some quite odd sizes, 7/8 x 24tpi among them, so 24tpi is not unlikely. I have checked my own and that, like yours, is 3/4 x 24tpi.
Thanks everyone for taking so much trouble to check your bikes. I have ordered a tap from Tracy tools
Thanks again
Bob
I have a nmber of rear wheel and front wheel "nuts" if they can be called that. Some are pretty worn.....see sketch of the rear variety.
Vic
Thanks for the info Vic. My key need was the hexagon nut the fits on the 3/4 inch thread of the component you have sketched which looks like part 5013. Mine is serviceable although the slots are a bit dodgy.
I have bought steel and the tap for the nut.
Thanks again
Bob
The clutch centre nuts are 24 tpi too. Seems to be a bit of a Sunbeam eccentricity!
Cheers Rick
26 Tpi on the earlier gearboxes..i've made both...John