Welding aluminum steerer stem
#1
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Welding aluminum steerer stem
Does anyone in the framebuilders forum, with extensive experience welding aluminum, offer a repair service? I have a handlebar/steerer stem about a foot long (for a folding bike) that had an integrated (welded) handlebar clamp that cracked. I would like the handlebar clamp sawn off and then a smaller aluminum tube inserted telescopically into the tube maybe four inches or so, protruding from the top about two inches, and welded in place there, so that a standard handlebar stem could be bolted onto it. The proprietary replacement from the manufacturer is just too costly.
I've included a picture of the stem with a pencil mark in the approximate location where I'd like the outer tube to be cut.
Is that kind of repair job even feasible?
I've included a picture of the stem with a pencil mark in the approximate location where I'd like the outer tube to be cut.
Is that kind of repair job even feasible?
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Last edited by timo888; 09-25-19 at 06:44 AM.
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Sure anything is feasible, many jobs might be best not actually done though
The crack looks to have been at the weld root, a common location for stresses to focus on and where undercutting often happens.
What's the alloys involved? If you don't know then seriously reconsider the repair. By your questions I hope you are not the person who will do the welding, that person is the one you need to qualify and trust with your face. Andy
The crack looks to have been at the weld root, a common location for stresses to focus on and where undercutting often happens.
What's the alloys involved? If you don't know then seriously reconsider the repair. By your questions I hope you are not the person who will do the welding, that person is the one you need to qualify and trust with your face. Andy
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AndrewRStewart
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#3
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Sure anything is feasible, many jobs might be best not actually done though
The crack looks to have been at the weld root, a common location for stresses to focus on and where undercutting often happens.
What's the alloys involved? If you don't know then seriously reconsider the repair. By your questions I hope you are not the person who will do the welding, that person is the one you need to qualify and trust with your face. Andy
The crack looks to have been at the weld root, a common location for stresses to focus on and where undercutting often happens.
What's the alloys involved? If you don't know then seriously reconsider the repair. By your questions I hope you are not the person who will do the welding, that person is the one you need to qualify and trust with your face. Andy
As for the alloy, no idea. I assumed 6061. Don't all the frame-builders here have personal electron microscopes?
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well, we all have a fully staffed metallurgical lab in the back.
Most aluminum alloys need post weld heat treatment. I'm not sure there are any people that work with aluminum that monitor this forum any more. There are only a few left in the U.S. Frank the welder used to hang around, but I think the C&V guys scared him off. If anyone would do this repair, he's the one.
Most aluminum alloys need post weld heat treatment. I'm not sure there are any people that work with aluminum that monitor this forum any more. There are only a few left in the U.S. Frank the welder used to hang around, but I think the C&V guys scared him off. If anyone would do this repair, he's the one.
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I'm not that far from you in South Jersey I could do the aluminum welding, but I don't have any way to heat treat it afterward. I would be willing to re-create the whole part in steel, if that works for you.
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I think steel is a great idea if that will work.
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It is hard to judge sizes. What is the outside diameter of your steer tube. Inside diameter?
I think your repair should be feasible, as long as you get adequately thick. I need some more practice with welding aluminum. I find it frustrating to deal with. Too cold and a mess. Too hot, and it just drops away. I think I need more practice with the stack of dimes.
In theory you can also braze aluminum, which might be an option for a lap joint as you suggested.
As far as the type of aluminum, one can conclude that you have a "weldable alloy". It would be best to get as good of a match as possible, but you should be able to choose a piece to splice with, as well as welding rod which should allow some flexibility.
I think your repair should be feasible, as long as you get adequately thick. I need some more practice with welding aluminum. I find it frustrating to deal with. Too cold and a mess. Too hot, and it just drops away. I think I need more practice with the stack of dimes.
In theory you can also braze aluminum, which might be an option for a lap joint as you suggested.
As far as the type of aluminum, one can conclude that you have a "weldable alloy". It would be best to get as good of a match as possible, but you should be able to choose a piece to splice with, as well as welding rod which should allow some flexibility.
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If you can find/machine a suitable tube to fit nicely inside the existing one and with sufficient overlap, couldnt you just bond it in place?
If the inner tube is plenty over engineered you could add a securing screw/pin to prevent an accident should the bond fail
If the inner tube is plenty over engineered you could add a securing screw/pin to prevent an accident should the bond fail
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I wouldn't be welding or gluing or any other unconventional repair. I finally understood what the OP wants, and I don't think it's a great idea. What I would propose is a custom stem that fits on the existing tube. It's possible that a seat post clamp would fit on that tube, in which case it could be slotted and a tube clamped inside.
I also wonder if it's possible to get this part and just skip the repair
I also wonder if it's possible to get this part and just skip the repair
#10
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My Plan B at present is to insert a steerer tube from another folding bike (Swift) into the tube in the photo (as it turns out, it fits almost perfectly and costs only $30 rather than the $300 the proprietary replacement would cost). To keep the inner tube from spinning inside the outer tube, I would drill a hole through them both and insert a cotter pin or an M4x40mm machine screw or something.
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#11
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trying to delete this
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#12
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It is hard to judge sizes. What is the outside diameter of your steer tube. Inside diameter?
I think your repair should be feasible, as long as you get adequately thick. I need some more practice with welding aluminum. I find it frustrating to deal with. Too cold and a mess. Too hot, and it just drops away. I think I need more practice with the stack of dimes.
In theory you can also braze aluminum, which might be an option for a lap joint as you suggested.
As far as the type of aluminum, one can conclude that you have a "weldable alloy". It would be best to get as good of a match as possible, but you should be able to choose a piece to splice with, as well as welding rod which should allow some flexibility.
I think your repair should be feasible, as long as you get adequately thick. I need some more practice with welding aluminum. I find it frustrating to deal with. Too cold and a mess. Too hot, and it just drops away. I think I need more practice with the stack of dimes.
In theory you can also braze aluminum, which might be an option for a lap joint as you suggested.
As far as the type of aluminum, one can conclude that you have a "weldable alloy". It would be best to get as good of a match as possible, but you should be able to choose a piece to splice with, as well as welding rod which should allow some flexibility.
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Did the manufacturer say why this isn't covered under warrantee?
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I wouldn't be welding or gluing or any other unconventional repair. I finally understood what the OP wants, and I don't think it's a great idea. What I would propose is a custom stem that fits on the existing tube. It's possible that a seat post clamp would fit on that tube, in which case it could be slotted and a tube clamped inside.
I also wonder if it's possible to get this part and just skip the repair
I also wonder if it's possible to get this part and just skip the repair
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AndrewRStewart
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#16
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I wouldn't be welding or gluing or any other unconventional repair. I finally understood what the OP wants, and I don't think it's a great idea. What I would propose is a custom stem that fits on the existing tube. It's possible that a seat post clamp would fit on that tube, in which case it could be slotted and a tube clamped inside.
I also wonder if it's possible to get this part and just skip the repair
I also wonder if it's possible to get this part and just skip the repair
What is involved in slotting the tube? Is that simply a matter of taking a dremel with a cutting wheel to it and then filing it smooth?
The OD of the tube is 35mm. The ID is 30.5mm.
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Last edited by timo888; 09-27-19 at 03:13 AM.
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Drill a 3/16" hole at the terminus of the slot. Use a dremel or hacksaw to cut a slot. Whatever you insert into it needs to fit fairly closely or it's not going to work. In this case, you probably don't care if it gets stuck. The bore size is slightly less than a 1 1/8" steerer, so that could be modified to go in there. If it were my bike, I would make a stem to fit the od. Granted, custom stems cost about the same as the manufacturer wants for the part, so it's not that attractive for you
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Of course, there is a risk of a fracture line. That is the most serious as it could involve separation.
The risk of twisting free likely would be more of an annoyance than a critical danger.
I've had a couple of stems that have turned (quill or threadless).
But, never have they pulled out. Of course, they have bolts which may still add friction.
Anyway, simply a loose stem may still result in a controllable bicycle, especially if the insert is rather long.
The two differences might affect one's choice of bonding processes, and how they might affect the end result.
There are a few stems for 1", 1 1/8", and 1 1/4" steer tubes.
Your point of seat post is good, and there may be a larger variety of rear Tandem Stoker stems, although they may be longer, with more adjustment that would ordinarily be desired.
Knowing the internal size, there are standard 1" quill stems, as well as 1 1/8", and I believe the equivalent of 1 1/4" quills (of course, those are steer tube diameters, not the actual stems).
Moderate adjustments in size can be made with shims.
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a 1 1/8" quill stem would almost work. They are pretty rare though
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I like the idea to slot and use a seat post clamp. A 34.9 clamp should work fine. The insert would need to be a machined part that goes from 30.5 to 28.6, so a standard 1 1/8" stem would fit.
It would be fairly easy to turn the necessary piece on the lathe from an 1.25"x .25" wall aluminum tube. Let me know if you'd like me to make that piece for you. I'm willing to do it for the cost of materials, if you can come pick it up.
It would be fairly easy to turn the necessary piece on the lathe from an 1.25"x .25" wall aluminum tube. Let me know if you'd like me to make that piece for you. I'm willing to do it for the cost of materials, if you can come pick it up.
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You should be able to pick them up at a local bike co-op. E-Bay?
Look for MTB's, and perhaps hybrids from about 2000 to 2005 or so. Cheaper MTBs and Hybrids?
Look for MTB's, and perhaps hybrids from about 2000 to 2005 or so. Cheaper MTBs and Hybrids?
Last edited by CliffordK; 09-27-19 at 04:43 PM.
#22
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I like the idea to slot and use a seat post clamp. A 34.9 clamp should work fine. The insert would need to be a machined part that goes from 30.5 to 28.6, so a standard 1 1/8" stem would fit.
It would be fairly easy to turn the necessary piece on the lathe from an 1.25"x .25" wall aluminum tube. Let me know if you'd like me to make that piece for you. I'm willing to do it for the cost of materials, if you can come pick it up.
It would be fairly easy to turn the necessary piece on the lathe from an 1.25"x .25" wall aluminum tube. Let me know if you'd like me to make that piece for you. I'm willing to do it for the cost of materials, if you can come pick it up.
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