Fork stanchion 1 1/8" inner thread top

[Greybeard]

It 's the inner thread of the tube that is damaged. When the top cap is screwed on, at one point it turns in a vacuum and therefore cannot be tightened. I contacted Tracy tools, he doesn't have this tool anymore... thread tap 15/16 20 tpi whitworth.
Rudelan

Hello, Rudelan. By describing the nut as turning in a vacuum, are you saying that the nut simply turns without gripping the thread? If that is the case then a tap wouldnt help you as it sounds like the inside threads have actually torn away. It would be possible to replace the inner thread with an insert the threads being cut on the lathe. It would mean machning out the top of the fork leg to take an insert similar to a helicoil repair but it would be a time consuming job, and need some sizeable machine facilities. It may be that a more cost effective option would be to simply replace the fork leg unfortunately.

Steve

[Mick D]

Hi

It certainly sounds like the thread in the stanchion has been stripped, will a brand new top cap screw in correctly? If so re-assemble the forks and don't over tighten the cap, (it doesn't need to be very tight as the pinch bolt is the main mechanism maintaining the fork in place). Don't be tempted to draw the stanchion into place with the top cap - use the correct tool if it will grip.

If a new cap or the fitting tool will not screw in and hold you will need to replace the stanchion, (there's not enough material for an insert to be easily fitted and the cost to do so would exceed that of a new item).

Regards Mick

[rudelan_LAPSED]

This problem is that of a friend who has a 1954 Matchless. The original stanchion was very rusty and bent. He bought a used stanchion after an ad. Apparently in good condition... at the end of the assembly, he saw that the inner thread was damaged.

[bitza]

I have just read my April old bike mart, there is a advert from a company in Leeds, C & I Treading Ltd. Climax Works, Leeds, LS 11 5 JY,
Turning and Welding, 40 years expertise say they specialise in Left and Right hand Threads, also custom made to your specification,
Phone number, 01132760808, or charlie@candithreading.com.