stripped threaded fork
 

Ok I have a common problem here, the threads on the fork have been stripped so that the headset can't bite and rocks. So heres my question: Short of replacing the fork, which has huge sentimental value (don't ask), is there any crazy way of making it work? Time, effort and money are no object (again huge sentimental value). I've been thinking of filling down the rest of the threads, using a shim and a quill stem adapter. But that doesn't allow me to keep the correct pressure on the headset.

Yes I know this is kinda stupid, but help me out here. Thanks.

I presume the original threads are damaged to the point where just "chasing" them with a threading die won't be enough.

I have heard of having a frame maker melt brazing brass into the damaged threads and then recut the threads using the proper threading die.

A shorter stack headset is another option if your current headset stack height allows for it.

have a frame builder replace the steering tube....

How about telling us how many threads are ****ed. Pictures would help as well.

Bump since I think the same thing happened to me, see attached.

I have no idea how this happened. It's an old used fork with a basic, bought-new headset. I've commuted daily on the bike for over a year since I replaced the headset. Suddenly it started loosening up while I ride. Tightening the top nut just hits the stop, even after I added two spacers to the stack.

I'm willing to replace the fork, but I think I might have a hard time finding a shop that stocks used parts around here. Would this eventually stop loosening if I added more spacers? Could I add another threaded nut / old top race to the stack, to lock against the top nut like the current top race is supposed to?

1" threaded forks can still be found. Nashbar even has a 1" threaded carbon fiber 700c fork.

I hope that is just a paint crack on the weld at the top tube/head tube joint on Capt. Cool's frame.

That was my first thought... the brass threads should last longer, too.

It's not the top nut that needs to be locked; it's the cup. Looking at that pic, it's no wonder the cup comes loose; you can't tighten it in the first place. If your LBS has an appropriate die and you have access to an oxy set, I recommend the above suggestion.

Yeah, that's a bit disconcerting... bears investigation.

Neat, JensonUSA has a steel one for $26. That's a good backup plan.

Me too.

It's an old gaspipe frame, heavy and solid, but I should look it over again. Thanks.

I should be able to tighten the cup by tightening a nut above it. And if I "lock" two nuts together above the cup, the cup won't go anywhere. Right?

Having a frame-builder with brazing-rod would be idea - but also more expensive than replacing same. Certainly in the long run. If you have a classic bicycle where substituted forks would harm it's value - go ahead with the frame-builder. And hang it on your wall.

1 inch forks are available and a mitre-block is pretty cheap - or have your LBS assist.

Tally Ho!

That type of damage usually is the result of riding with the headset loose. Spacers won't fix the problem since there is insufficient thread to hold the threaded cup in place. I've fixed many forks like this by melting brass into the damaged area and cutting new threads.

I will look for a replacement fork. But I still don't see how this follows. If I could tighten down a nut above the spacers to set the cup, and then another nut on top of that to lock it, why wouldn't that hold?

Most likely the steering tube is pressed in, and so it can also be pressed out and subsequently replaced by and machine shop or, as suggested, frame builder.
Sometimes improvising a little bit is the most cost effective way to proceed. The purpose of the top nut is to preload the bearings of the headset, providing the radial and axial stability the application requires. If you can find an appropriately sized spacer and engage the thread where it's not stripped, go for it :). You might even put a dab of loctite on those threads to keep it from backing out ever.

Here is an interest trick that may work from http://ratrodbikes.com/forum/viewtop...p=13190#p13190 (scroll down for more info. Alot of the images are missing but you should get the idea)


grind of the top beveled/cap part of the nut so it will look/act like any ordinary nut. You would be able to screw it down the fork tube as far as you want without it bottoming out.

Then cut the nut in two so you have a right and left half.

Wrap the 2 halves around the fork tube below the bad spot thus putting the nut back together. Vice grip the 2 halves to hold them together.
Now unscrew up and over the bad spot.

Without intact threads, there's nothing to hold the cup in a stable position. If you adjust it so the bearings rotate smoothly, the cup will wobble on the steer tube (try it if you don't believe me -- it may work for a short while in the work stand, but not on the road in the long term). If you adjust it so the cup doesn't wobble, the the bearing will not turn smoothly.

You really do need to either fix the threads or replace the fork.

+1 agree with this.

I think that the op is thinking is to press the race cap with spacers and similar to a threadless headset. This will not work well because of the existing damage to the threaded portion of the steerer. there are no longer the close tolerances neccessary to prevent the race cap from wobbling and will eventually cause more damage to the steerer and the races and bearings. This is something that should be fixed the correct way.

Thanks, this is what I was looking for. That makes sense. Replacement fork it is.