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Old 11-02-06, 08:27 PM   #1
TheSergeant
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Welding together a steerer tube cut too short!

I'll try and be as brief as possible for you all:

Basically I cut the steerer tube on my all steel (lugged crown, chromoly steerer) fork far too short. I scored the tube with a screw driver, but apparently so did my headset. I ended up cutting the wrong score line. And essentially ruining my fork.

A buddy that I work with saw how upset I was and took the fork to some professional shop welders who are customers of ours. They cut the tube down flush on both sides and welded it perfectly (and I mean perfect, we measured all the way around) together. They then sanded it down so it's barely noticeable except for a section where they sanded it. The inside shows some beading as well.

The part that where the tubes joined sits a little below the top cup on the headset inside the headtube. It is on a cyclocross bike. I weigh 165lbs.

My question to you all is....

Will it hold and would you trust it?
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Old 11-02-06, 08:51 PM   #2
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How's the weld look on the inside of the tubing? Personally I would've re-inforced the inside with a sleeve. A lot depends upon the quality of the welder, rod-material used, gas, technique, etc.

There was a debate on this welding tubing together presented at the hearings after Ayrton Senna's crash...
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Old 11-02-06, 08:52 PM   #3
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CrMo welds well and retains its properties after welding. It sounds like they knew what they were doing. When steel fails it is a graceful failure (doesnt shatter). I would use ut if it were still straight. The beading on the inside may be a problem with a quill stem.
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Old 11-02-06, 08:54 PM   #4
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If these are indeed professional welders then yes and yes.
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Old 11-02-06, 09:05 PM   #5
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I have a fork that had its steerer tube extended by a local framebuilder. He uses a sort of plug to connect the old and new parts of the steerer tube in addition to the weld.

It's held up pretty well so far.
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Old 11-02-06, 09:31 PM   #6
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Sorry, I think that this is dangerous, especially on a CX bike. The stresses that joint will be experiencing will be tremendous, more so than on a bike ridden primarily on road. If the welders used some sort of internal splint or sleeve this may strengthen the steerer tube a bit, but just the same I would spring for a new fork for peace of mind.

Last edited by bykerouac; 11-02-06 at 09:55 PM.
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Old 11-02-06, 09:53 PM   #7
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Will it hold and would you trust it?
Sorry my face is too valuable to lose descending at 80kph.
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Old 11-02-06, 11:04 PM   #8
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Quote:
Originally Posted by Ganesha
If these are indeed professional welders then yes and yes.
I do a little welding myself. Sounds like these guys were pretty good. It's not rocket science, and it holds REALLY well. I'd ride it.

If you decide not to "risk it," let me know and I'll take the forks off your hands.

The only thing I could see going wrong is if it wasn't welded exactly straight, you'll probably go through headsets pretty rapidly. No harm in just trying it out. You can replace with a $30 headset if you have to get a new fork anyway. Not the end of the world.

I wouldn't worry at all about it breaking.
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Old 11-02-06, 11:23 PM   #9
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I've been told that welds are often stronger than the steel itself. If the shop did as fine of a job as you described, it should be fine. I still would have sleeved it, but it's probably not needed.
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Old 11-03-06, 01:10 AM   #10
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The haredest part in welding tubing is getting the weld so it doesn't distort the surrounding metal out of straight line as each pass is made. If as you say you can't find anything amiss with straight edges (or a length of angle iron that you can rotate the tube in to see if there is any out of true)... go for it.

Concerns about welding stuff on bikes make you wonder how modern steel, aluminium and titanium frames are assembled... with sticky tape?
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Old 11-03-06, 03:04 AM   #11
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Personally, I wouldn't have done it. You said that the fork had a crown and the tube was brazed into it. You could have sent it to a frame builder and they could have taken out the short tube. Then they braze in a new full length one. It would have been one piece and very strong. You can still have that done. A steering tube failure can catastrophic.

Tim

Last edited by cs1; 12-31-07 at 01:31 AM.
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Old 11-03-06, 11:43 AM   #12
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Originally Posted by cs1
Personally, I wouldn't have done it. You said that the fork had a crown and the tube was brazed into it. You could have sent it to a frame builder and they could have taken out the short tube. Then they braze in a new full length one. It would have been one piece and very strong. You can still have that done. A steering tube failure can catastrophice. Be forewarned.


Tim
Whatever makes you think that would be any better? Reheating the crown and lugged area around the forks for a second time by brazing is not what I would think is prudent, irrespective of the skill of the framebuilder. At least at the *top* of the steerer tube, the reheating/annealing issues are not such a moot point because the steel is thicker, hasn't already been heated from prior welding, and it's likely the welding shop used TIG or MIG to do the job, and hence kept heat issues to a minimum. It is not as though the steerer tube at that point is sustaining any substantial stress to threaten its integrity. If it was, things like aheadsets or quill stems that rely on friction fit wouldn't work.

It sounds to me as though the professional welding shop knew exactly what they were doing. I suspect they used a plug in the tube to ensure it remained straight and distortion-free. I'd be interested to know.
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Old 11-03-06, 12:52 PM   #13
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FWIW I had a framebuilder cut&weld my cromo steerer (switch to threadless). He has done a million of these, I am sure. I trust it completely.
If they are decent welders and knew what material it is, then it's as good as new.
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Old 11-03-06, 04:01 PM   #14
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Quote:
Originally Posted by Rowan
Concerns about welding stuff on bikes make you wonder how modern steel, aluminium and titanium frames are assembled... with sticky tape?
No, helicopter tape. Ooops sorry. Wrong thread.
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Old 11-04-06, 01:11 PM   #15
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Personally I find this thread amusing. As I read posts over the past months the majority of folks rave about steel (CroMo) bikes because if they are in a wreck or fail in any way they can be welded back together. Those posts appear most commonly in discussions about carbon bikes/components. Now I normally just chuckle at such a thought, I would probably just buy a new bike. This time folks seem to be exhibiting a caution against trusting a welded CroMo part. Interesting. Which is it to be? My steel bikes are welded together and I trust them.
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Old 11-04-06, 01:29 PM   #16
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Properly done welds are as strong as the parent material, many custom motorcycles have butt welded joints, and if they are strong enough for a 500lb machine at 70mph, it's hard to believe that the same type weld won't work on a 20lb bicycle at 30mph

if percieved strength is the issue, look at fillet brazed frames, then remember that brazed joints are only 1/3rd as strong as the parent material, and that all stresses on the bike are handled by them with no issue. Same goes for aluminum frames.

ken.
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Old 11-04-06, 10:25 PM   #17
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Just seems a little too sketchy for me. No dice. I would get a new fork.
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Old 11-05-06, 12:35 AM   #18
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It's your call, but it I can't see any reason not to ride it. A professional welding shop made the repair, and your description indicates that they did a top notch job.

I understand that a failure of some joints is far more dangerous than others, but this whole debate is nuts to me. Whether we realize it or not, most of us regularly stake our lives on welded joints. The difference in this particular situation is that we're all focusing on it.

Actually, there are at least two other important differences. In this case, the OP has some background information about the people that prepped, welded and finished this joint. The OP has also thoroughly inspected the joint (to the best of his/her ability). Most of us don't know much about every critical weld, and we generally know less about the welder that laid the bead.

In the end it's your call. Use your best judgement.
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Old 11-05-06, 02:07 AM   #19
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So, for the moment I'm going to ride on the fork. I dont' have any reason to believe that the fork is going to fail other than "heresay". I'll likely upgrade to Nashbar's Carbon Cross Fork. It's $140 right now but I'm going to wait until they have a coupon code again. I would have preferred to have upgraded later rather than sooner, but these recent events have persuaded me to act sooner. The fork is Surly's cyclocross fork, on a Surly Cross-Check frame. It's my understanding that Nashbar's fork will save me 1/2 pound and at the same time add a little peice of mind.

The welders did the job for free, so I can't complain. Atleast I have a finished bike to ride. I'll hold off on pushing the bikes limits until I order a new fork.

Thanks for all the input guys! sd
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Old 11-05-06, 04:01 AM   #20
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Quote:
Originally Posted by Rowan
Reheating the crown and lugged area around the forks for a second time by brazing is not what I would think is prudent, irrespective of the skill of the framebuilder.
The OP asked what we thought. I told him what I thought based on what I was told by a professional framebuilder. IMO, I would rather have a new fork first. If not a new afork, then a new steerer tube instead of a repaired one. You might think a repaired one is fine. If you do then that's fine for you.

To the original poster, good luck and let us know what happens down the road.

Tim
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Old 11-05-06, 06:55 AM   #21
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To answer the naysayers again, quoting a classic "Do you trust a weld to keep the BB attached to your frame, but not to turn your wheel into the corner?"
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Old 12-31-07, 12:10 AM   #22
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Quote:
Originally Posted by TheSergeant View Post
So, for the moment I'm going to ride on the fork. I dont' have any reason to believe that the fork is going to fail other than "heresay". I'll likely upgrade to Nashbar's Carbon Cross Fork. It's $140 right now but I'm going to wait until they have a coupon code again. I would have preferred to have upgraded later rather than sooner, but these recent events have persuaded me to act sooner. The fork is Surly's cyclocross fork, on a Surly Cross-Check frame. It's my understanding that Nashbar's fork will save me 1/2 pound and at the same time add a little peice of mind.

The welders did the job for free, so I can't complain. Atleast I have a finished bike to ride. I'll hold off on pushing the bikes limits until I order a new fork.

Thanks for all the input guys! sd
I'd be interested in hearing how this held up.
I've got a threaded steerer tube that broke at the base of the threads, was probably going to replace the fork rather than weld.
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Old 12-31-07, 12:37 AM   #23
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Interesting thread.

I'd love to see some detailed pics of the work they did.

Also, I'd probably ride it.
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Old 12-31-07, 08:46 AM   #24
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Yes

There is no doubt in my mind, if they knew what where doing that it will hold.
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Old 12-31-07, 10:05 AM   #25
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As the owner of a welding and machine shop I've had considerable experience with welding thin-walled tubing, 4130 aircraft structures etc.

The OP indicated there was 'some beading' visible inside the tube. Generally a repair of this type is done with another short piece of tube inserted inside the two parts to be joined. Then when the welding is done it is easy to assure 100% penetration throughout the cross-section of the tube. If the weld is done without a place for the root pass . . . and if the inside of the tubing is not purged with an inert gas . . . you will be left with a decarburized area, surface roughness, and a possible place for failure.

The difference between a weld with two pieces of tubing butted together [with the outside bead removed as in the OP's example] and virtually all the other welds on a steel frame is that most of the welds are fillet welds . . . with considerable filler metal remaining to reinforce the welded area.

The welding shop may have done an excellent job on the repair. However, considering the importance of the repaired part . . . I'd opt for a new fork.

DON
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