Chasing hub axle threads?
 

I recently bought a nice Campy record high flange hub, and when it came to me the lock nuts were just barely threaded on. I assumed this was from the former owner checking a date code. When I went to tighten them down, I found the locknuts would only go a turn or two before jamming up.

You're probably thinking what I was thinking: someone swapped the axle and hardware for a non-Italian axle, but kept the lock nuts.

Well, I went to unthread everything to pull the axle and lo and behold the cones are genuine Campy marked 10x26. They thread just fine until they get to the ends of the axle and won't come off.

A closer look at the axle ends shows the threads are quite smashed. I would presume this is from being mashed into the dropout hundreds of times?

https://cimg6.ibsrv.net/gimg/bikefor...276e5a0410.jpg


Anyway, is there any hope of "chasing" these threads so th lock nuts can go on?

Yes, there is a tool for that. Specific files for specific threads. We have a few sets of them at the shop. Doubtful you'll be showing up in Philly with your wheel though. The files do exist though! Someone out there has to have one.
Phil

Here is one on Amazon:

Thread restoring file

It has a 26 tpi face. Many others do not have 26 tpi.

Campy rear axles from this period are 10m x 26 TPI with 55 deg thread angle. This is a thread size that is about as obscure as it gets. Not a chance of finding a die this size. Even it you found one the a new axle would be much less money. I would take the cone and lock nut off of the other side so you can remove the axle from the hub. Hold the axle on the untreaded center portion, soft jaws in a vice for instance. Unscrew the cone, it's made from hardened bearing steel so it will force the soft damaged axle thread back into shape. Worst case, you need a new axle and cone. If you want to avoid the chance of ruining the cone, just cut the damaged thread off of the axle with a hack saw and file the end smooth. In this case you will need another axle. Jim Merz

You could also use a triangular file to carefully remove the smooshed part of the the thread. You will need one of the small triangular files. You only need to remove a small amount of material that has been pushed into the area where the mating thread wants to go.

Another way is if you have a spare Campagnolo cone or another 10mm x 26 tpi cone, cut a groove into it the threads on the cone to make it into a die and run it onto the axle. You could also grind a lead-in to the cone so that it cuts more progressively. You would be making a thread die out of the cone.

Just had to do this, used a triangular file - with a loupe it's a doddle, 5 minutes.

And if you don't have - or want to use - a vise to hold the axle just jam the cone and locknut on the other end together, and hold the jammed cone when you unscrew the cone-which-won't-unscrew.

If it's just the last one or two threads, you could just shorten the axle by that much. Axles of this type are almost always a few mm longer than they need to be.

The threads don't carry the weight of the rider, the axle nuts do, once the QR is tight. So even a mm or two of axle stickout past the locknut is enough to locate the wheel while closing the QR.

This isn't idle speculation; I've done it multiple times, and Saint Sheldon himself has approved this.

If you need to remove more than one or two mm, you can shift the axle over to split the width reduction between both ends.

Another tip, just force the cone to thread all the way off the damaged side (holding the axle by the middle unthreaded part), and it'll re-form the threads at least partly. The cone is harder metal than the axle, so little chance of damaging the cone. I'd probably do that only after shortening the axle by a thread or three.

This is great advice from ybulgie ; I forgot the cones are hardened steel and I was afraid the axle steel was harder than the hardware. I'll try to file a time amount out and then "chase" it with the cone and see if I can clean it up.

As far as shortening the axle, I believe this is a 120mm but I will double check.

It is unlikely that you will get a file to cut grooves inside the cone, it's RC62 or something hard. Just back it off over the damaged threads. Put some oil on first.

Jim Merz

Serious question, although I probably will never face such a predicament: Would running a standard 10 x 1 (25.4 tpi) 60° die just over the damaged outer threads help, or would it make matters worse and cause mobs of angry C&Vers appear with torches and pitchforks?

In my conversations with John Allen, I seem to recall he experimented with zero axle showing past the lock nut, and with a firmly-applied QR no issues or movement at all.

Not sure if you have tried to thread Italian hardware on a non-Italian axle, but you don't get very far. I think this would be a bad idea.

Jim (and others), if you don't already know about these fellows, you should.
Thought they do not have such a size in their catalog I'd bet a fiver they would make one.
They do have just about every other cycle-related threading tool - and not too dear either.

www. tracytools.com

Easy solution for this problem
 

All these answers about purchasing files and dies require more money than just getting another axle. The comment by oneclick mentions tracytools. I looked at the webpage, no dies in this tread size. Americans will not be able to purchase anything shipped using post from outside of the USA starting today due to onerous import restrictions. Here is a NOS genuine Campagnolo Record rear axle that is suitable for a 6 speed, 126 OLD hub as shown in the original post. $20. I also have a NOS Gipipemme rear hub that has a M10 x 26 tpi 55 deg threaded axle. It is about 6mm longer than the 6 speed Campy axle. The cones, balls, locknuts and washers all interchange with the Record rear hub. This axle does not have grooves for the tab washer. The hub body has a French freewheel thread, M34.7 x 1, not very useful but the axle hardware is. $20. Shipping at my cost, should be around $5. Jim Merz
https://cimg8.ibsrv.net/gimg/bikefor...0946894a57.jpg
https://cimg9.ibsrv.net/gimg/bikefor...ec68b79cac.jpg

I would strongly advise not having a custom die made, even if it were cheap. Which of course it won't be. I doubt even Campagnolo has one of those weird M10 x 26tpi dies, since their axle threads (back then) were rolled, not cut. The other M10 x 26 tpi thread they made, the screw that attaches the R. der. to the dropout, was almost certainly made on an automatic screw machine using a single-point tool, not a die.

But lets say you bit the bullet and had a custom die made, now what? The problem is, how do you start a threading die on a screw with the first couple threads mangled? There's no way to start it in-phase with the good threads farther down, so the die will probably start cutting out of phase with the good threads, and ruin all the threads, even the previously-good ones. I'm not even talking about the problem of starting the die aligned with the axis of the part; that can be achieved on a lathe, or with some sort of custom-made pilot on the die holder (but you have to make the pilot, it's not a stock part anyone sells). But no amount of skill or technology will overcome this phasing problem; only blind luck will save you, maybe one out of a thousand tries.

The only way I know to do this precisely (not counting the thread file or triangle file, which are only approximate) is on a lathe, with a single-point cutting tool. I could do that, but that's putting $100 worth of labor into saving a $20 part. Even though I have a lathe, I still would fix that axle with a triangle file, or by just forcing the cone over it as I mentioned earlier. Or just cut the mangled end off, and re-center the axle with less stickout on both ends.

Maybe it could be done with a segmented die that can be expanded to go over the bad threads, then closed onto the good threads, and run in reverse to re-cut the mangled thread. If one of those existed in M10 x 26 tpi, which they almost certainly do not. I have no experience with those 3-part segmented dies, only heard of them, but I believe they are large and super-expensive, and run on a dedicated machine. But now I'm being ridiculous, no one is going to spend five or six figures to make a custom tool to repair that $20 part.

The only segmented expanding die I've even heard of was owned by Tesch, who made his forks in big batches with long unthreaded steerers, the cut them to length as needed and added the threads last. As you may know, 1" x 24 tpi threading dies exist, but pretty often they screw up (no pun intended) and absolutely ruin all the threads. They cut beautifully going down, but then something goes wrong while unthreading the die back up. The expanding die gets around that, and saves time, by opening after the threads are cut, never backing up. The shop where I worked sometimes sent a fork to Dave to have that done, if the fork was valuable enough to be worth the round-trip shipping and the time it took. Not a service he offered to anyone, but we had a special relationship because he bought his lugs, BB shells and fork crowns from us. He saved our bacon a few times. Or at least we didn't have to make a new fork and paint it to match, sometimes the only other choice.

I still like threaded headsets and quill stems, for sentimental reasons, but man what a PITA those steerer threads were sometimes!