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-   -   Fork thread damage (https://www.bikeforums.net/classic-vintage/1159830-fork-thread-damage.html)

vintagerando 11-08-18 07:06 PM

Fork thread damage
 
I picked up this fork on ebay. The headset cups were strategically left on, hiding the damage. The damage goes all the way around; more extensive than the photo shows.
Fixing this would be expensive, correct? I had communications with Seller prior to buying; i got the feeling he know little to nothing about bikes. The damage looks shiny and fresh. I think he just took a pipe wrench and forced the headset off. I have to decide if I want to do a return.
The bit of reading i did, it appears to be a bigger job than I could do. The threading metal to stripped right off in places; no metal to re-thread.
Any thoughts? https://cimg0.ibsrv.net/gimg/bikefor...0a8f360b2c.jpg

JohnDThompson 11-08-18 07:51 PM

It's hard to tell from the picture whether the threads are damaged or just clogged with aluminum debris from an aluminum headset part. If the latter, simply chasing the threads with a die or thread file may be all that is needed.

If the threads are truly damaged, the damaged area can be filled with brass and new threads cut into the brass. This is a job for a framebuilder, but it's not particularly difficult if you have the tools and equipment. The threaded portion of the steer tub is far enough away from any visible painted areas on the fork, so paint damage is unlikely from the brazing heat.

3alarmer 11-08-18 08:25 PM


Originally Posted by vintagerando (Post 20654779)
I picked up this fork on ebay. The headset cups were strategically left on, hiding the damage. The damage goes all the way around; more extensive than the photo shows.
Fixing this would be expensive, correct? I had communications with Seller prior to buying; i got the feeling he know little to nothing about bikes. The damage looks shiny and fresh. I think he just took a pipe wrench and forced the headset off. I have to decide if I want to do a return.
The bit of reading i did, it appears to be a bigger job than I could do. The threading metal to stripped right off in places; no metal to re-thread.
Any thoughts? https://cimg0.ibsrv.net/gimg/bikefor...0a8f360b2c.jpg

...have you tested it in the frame you want to use it in ? If the head tube and stack height of your chosen headset in use is enough shorter than the bike it came out of, you should be able to just avoid the portion with the damaged threads, and shorten the fork steerer a little bit. But yeah, I can't tell whether the threads are damaged, or you just have a bunch of aluminum clogging things up in there.

Clean the threads up with a wire brush and see where you're at then.

vintagerando 11-08-18 08:32 PM

It was sold with the old headset screwed on by hand. The head set cups, and lock nut, spacer, etc. was hiding the threading. When I go the fork, I hand screwed the headset pieces off; shreds of alum fell out. This was recently damaged and the headset screwed back on to cover the damage.

xiaoman1 11-08-18 08:46 PM

Is it just me or are the threads damaged vertically ..upper left of the tube? If not wire brush and chase it with a headset nut a little at a timeIf that does not work send it back.
Ben

vintagerando 11-08-18 08:56 PM

https://cimg3.ibsrv.net/gimg/bikefor...e60f5fa098.jpg
https://cimg4.ibsrv.net/gimg/bikefor...1d649d1d7d.jpg
more pics

vintagerando 11-08-18 08:59 PM


Originally Posted by xiaoman1 (Post 20654883)
Is it just me or are the threads damaged vertically ..upper left of the tube? If not wire brush and chase it with a headset nut a little at a timeIf that does not work send it back.
Ben

No, what you are seeing is that vertical space for the tooth of the locknut. Not sure if I am using the right terms; on the locknut and/or spacer is a tooth that prevents the headset parts from slipping (i believe)

randyjawa 11-08-18 09:01 PM

I have seen this sort of steering tube damage several times. It is caused when the tap washer wants to turn with the nut, when undoing it. Generally a little wire brushing and, perhaps, some smoothing with a smooth file is all that is needed to get it all good enough to use and without any added danger.

Perhaps there are other issues that my old eyes can't see. Were it my fork, I would give it a try. I would also contact the seller and let him or her know that the fork arrived damaged. Who knows, he or she might be pretty decent about it.

xiaoman1 11-08-18 09:11 PM


Originally Posted by vintagerando (Post 20654891)
No, what you are seeing is that vertical space for the tooth of the locknut. Not sure if I am using the right terms; on the locknut and/or spacer is a tooth that prevents the headset parts from slipping (i believe)

Great, try the wire brush and chase it.... it should be all good.
Best, Ben

vintagerando 11-08-18 09:16 PM


Originally Posted by randyjawa (Post 20654895)
I have seen this sort of steering tube damage several times. It is caused when the tap washer wants to turn with the nut, when undoing it. Generally a little wire brushing and, perhaps, some smoothing with a smooth file is all that is needed to get it all good enough to use and without any added danger.

Perhaps there are other issues that my old eyes can't see. Were it my fork, I would give it a try. I would also contact the seller and let him or her know that the fork arrived damaged. Who knows, he or she might be pretty decent about it.

The threading is gone in the effected areas; nothing to file and clean up; I paid a good price for it. I am protected by ebays Buyer Guarantee. Maybe it wasn't done on purpose, but the headset parts (incomplete) were hand screwed back on covering the damage ( in photos on ebay) . I would not have paid what I paid if I knew that. I guess what i am trying to determine; is there going to be an issue when I try to use this fork. If so, I need to act now and return it.

randyjawa 11-08-18 09:27 PM

I am pretty sure that I could repair the threads and that the strength lost would not be significant enough for me to worry about. The damage is above the tab washer, Only the lock nut will be effected and it does not have torqued all that tight, in my opinion. That said...

Were it me, I would ask for a complete refund rather than have something on my bike bother me, even if it is not a serious issue. Based on your description of the seller's lack of vintage bicycle knowledge, it could be an honest mistake. However...

The damage should have been disclosed and shown in the pictures and a full refund could be had, based on that undisclosed damage.

Raleigh74 11-08-18 09:31 PM


Originally Posted by 3alarmer (Post 20654862)
...have you tested it in the frame you want to use it in ? If the head tube and stack height of your chosen headset in use is enough shorter than the bike it came out of, you should be able to just avoid the portion with the damaged threads, and shorten the fork steerer a little bit. But yeah, I can't tell whether the threads are damaged, or you just have a bunch of aluminum clogging things up in there.

Clean the threads up with a wire brush and see where you're at then.


^ I think this is your answer, and if in doubt return and wait it out for something better. My $0.02

JohnDThompson 11-08-18 10:14 PM

A thread file or chasing with a die ought to be able to clean that up.

obrentharris 11-08-18 11:00 PM

If you are uncomfortable cleaning up the threads yourself you could take it to a local framebuilder or shop with the correct die. Get a quote from them and ask the seller for a refund of that amount.
Brent

MarcoBianchi 11-09-18 01:02 AM

1-Refund.
2-Framebuilder.
3-DIY
https://www.amazon.com/Nicholson-Thr.../dp/B07GZ3WC9B.

madpogue 11-09-18 08:18 AM


Originally Posted by randyjawa (Post 20654895)
I have seen this sort of steering tube damage several times. It is caused when the tap washer wants to turn with the nut, when undoing it.

This explains it best, when you look at the location, and the fact that it extends one direction from the slot for the notch on the washer. So the damage should coincide with the location of the washer, and you should be GTG. I've always considered that design to be lacking; it's far too easy to turn the cup and locknut at the same time, thus turning the washer and doing exactly ^^^^^^ this. The slot should be deeper and the notch larger, or there should be multiple slots/notches, or something.

randyjawa 11-09-18 08:44 AM


The slot should be deeper and the notch larger, or there should be multiple slots/notches, or something.
Perhaps but that would cause other issues, in my opinion. On more than one occasion, I have seen that groove in the steering stem actually split, thanks, primarily, to the stem being inserted too little. Once that happens, repair becomes wayyyy more difficult.

Knowing the turning tab washer to be a problem with many bikes, I lubricate the faces of the tab washer and top nut. This helps to prevent the washer from trying to follow the top nut during installation and removal. It does not always work, but is better than saying "oops". My opinion, of course.

belacqua 11-09-18 08:55 AM

I would not sweat it too much. This damage is common and seems to happen when people try to force non-rotating keyed spacers to "unscrew" when adjusting or removing the headset.

I have had really good luck just cleaning up the *remaining* threads and using the fork as is. The threaded components still go up and down all right once the threads are cleaned up, and since the stripping occurs where the spacer goes, there's usually adequate threading left for the races and locknut to seat.

PS now I see [MENTION=84826]randyjawa[/MENTION] and [MENTION=9425]madpogue[/MENTION] have already pointed this out more precisely and accurately

lacro 11-09-18 02:35 PM

I don't think that's something major to worry about. I would fix it and carry on. I find these thread files very handy for cleaning up damaged threads. A re-threading die (chaser) tends to cause more tear out, but the thread file fixes just the damaged area.

https://www.mscdirect.com/browse/tnp...hoCSxMQAvD_BwE

randyjawa 11-09-18 10:00 PM


I find these thread files very handy for cleaning up damaged threads.
Ah, my failing memory! I completely forgot that I have a set of thread chasing files, one in metric and the other imperial. That said, I still prefer a small triangular file for cleaning stem threads - lower left in picture...
https://cimg4.ibsrv.net/gimg/bikefor...d70671347d.jpg

vintagerando 11-09-18 11:33 PM


Originally Posted by randyjawa (Post 20656458)
Ah, my failing memory! I completely forgot that I have a set of thread chasing files, one in metric and the other imperial. That said, I still prefer a small triangular file for cleaning stem threads - lower left in picture...

Well, what do you know. I actually have one of those triangular files. Is the goal to re-shape the thread or remove the squashed threading?

vintagerando 11-10-18 12:43 AM

https://cimg7.ibsrv.net/gimg/bikefor...cc5fe0b096.jpg
https://cimg8.ibsrv.net/gimg/bikefor...4250aa5b32.jpg
Just made a new discovery. Where the threading was stripped, the tube is collapsing inward, in other words cracking.
I would say its clearly dangerous now. The question now is, can it be cut and still be usable. Without building up the bike the fork would go on, how would I know if its going to be long enough when cut?

xiaoman1 11-10-18 10:08 AM

Send it back and end the worrying...IMHO it is not worth the concern.
Best, Ben

madpogue 11-10-18 10:13 AM

If it's long enough for the intended head tube now, it would be too short after cutting it. It might end up long enough for a frame with a shorter head tube, depending on how far down it's threaded,

But why is the inside of the steerer tube so damaged in the first place?

GrainBrain 11-10-18 11:15 AM


Originally Posted by vintagerando (Post 20656554)
https://cimg7.ibsrv.net/gimg/bikefor...cc5fe0b096.jpg
https://cimg8.ibsrv.net/gimg/bikefor...4250aa5b32.jpg
Just made a new discovery. Where the threading was stripped, the tube is collapsing inward, in other words cracking.
I would say its clearly dangerous now. The question now is, can it be cut and still be usable. Without building up the bike the fork would go on, how would I know if its going to be long enough when cut?

Bah what a bummer. Clearly damaged from the lock ring tab pushing in. Plus the ID looks like the steerer was rusted in then forcibly turned to remove. Unless this is a unicorn better condition forks aren't hard to find


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