Help identify a thread

I don't "know" what the thread is but its most likely to be cycle 26tpi. what i usually do in cases like this is to compare with my stock of nuts and bolts where i know what they are. I also have sets of taps and dies to compare with.Most bought at boot sales for peanuts.

Can't help with the thread - but it should have and it DOES NEED a special spring washer. Available from the usual suspects. Otherwise the rotor will come loose and wreck the stator, and damage the woodruff key and crankshaft keyway.

Skip previously wrote:

Once you know the diameter & the TPI, your good to go.

Not quite! There are the thread angle and profile to consider. Luckily these are not generally to worry about on old Norton engines. British threads are usually 55 deg (but BA threads found on bikes are 47.5) and metric or US threads are 60 deg.

One parts source I have states that for part number 465909 cross references to part number 01-20692 and that cross references to 01-000292 which states that is a 5/8X20tpi The books do not state whether it is right hand or left hand thread but I presume that it is right hand as there is no mention of it being left handed in the service manual.

Mike

5/8 - 20 is a likely size. CEI threads in larger sizes were made in 20 tpi as well as 26. 20 would seem a sensible choice. If you want to make a nut, the biggest problem might be finding the correct size hexagonal bar.

Colin.

Previously wrote:

One parts source I have states that for part number 465909 cross references to part number 01-20692 and that cross references to 01-000292 which states that is a 5/8X20tpi The books do not state whether it is right hand or left hand thread but I presume that it is right hand as there is no mention of it being left handed in the service manual.

Mike

Yes Allen, you are absolutely correct on the thread angle, I should have mentioned that. If you figure the difference between 55 degrees & 60 degrees is 5 degrees (total included angle) thats really only a difference of 2 1/2 degrees per side. Factor in a 1 - 1 1/2 degree tolerance & old threads, one might not be able to tell the difference? But right is right & you are correct & a thread pitch gauge is a big help with that concern also. Thanks for bringing that up

Skip Brlund

Allen has not told the whole story. British Standard Cycle threads have a 60 degree thread angle, it is only British Standard Whitworth and British Standard Fine threads which are 55 degrees.

http://en.wikipedia.org/wiki/British_Standard_Cycle

Colin.