Steerer tube extending without welding

[baron von greenback]

It depends what you want to do with bike if it's only going to sit in garaga or a little cruisearound town or if your going to smash it down hills but can't you get the same guy that did silverfish yo eddy forks I don't know if there the same components but he did a real job

 

[novocaine]

You need the internal brazed sleeve below the quill, but you can keep the fork crown cool with running water, so no need to affect that joint.

A motorcycle steerer is under different forces to a bicycle, because (almost) all mc Forks are "triple clamp".

I've seen fork steerers extended with a mig bead in a rebate, then ground down too, but I've never done that - im uneasy with effects on the temper of the steel at and around the joint, and my mig welding looks like something the cat coughed up.

Cool it slow. Managed the heat by stitching it and having a heat sink inside the tube.

Still wouldn't do as you machinist suggests.

 

[Woz]

You need the internal brazed sleeve below the quill.

Ideally I would get a donor fork, cut off its steerer have the shop machine a sleeve and weld.

With the proposed idea, I can't see a quill stem going down there deep enough - what minimum insert about 70mm?

The idea of stuffing something solid and threaded at the top would allow to keep the threaded headset but then would need to use 1" ahead stem with a sleeve and internal thread for fixing the top cap. It could also be "pinned" to the steerer tube with something like a hammered in nail.

Why not just try one of these and convert the whole lot to 1" ahead?

https://www.sjscycles.co.uk/stems/p...1-inch-quill-to-1-18-inch-threadless/?geoc=FR


Would get you rolling but not period correct etc.

 

[Russell]

 

[bikeworkshop]

View attachment 969120

I know the feeling!

 

[klunkrider]

I’ve brazed several steerer extensions but never a threaded fork as it’s always seemed to me that the plug/slug/bung/whatever you want to call it would get in the way of a quill stem being inserted. Given a long enough steerer it’d certainly be possible to make it work but I’ve yet to come across that scenario.

Remember you can’t get too close to the crown as the steerer will likely be butted and that will get in the way of the insert and that’s without considering how the steel steerer/ali legs of the Cannondale fork are put together.

I’ve spoken to a retired industrial welder who reckons that the insert is entirely unnecessary, that a properly done butt weld is (at least) as strong as a piece of straight tube and that the insert is a “crutch which supports poor welding and poor alignment” or something like that. As an idea of the level he was at, he was working in nuclear power plants. Not sure that there’s many of us with budgets on par with nuclear power plants to pay for modifications!

 

[klunkrider]

Woops, double post.

 

[highlandsflyer]

I’ve brazed several steerer extensions but never a threaded fork as it’s always seemed to me that the plug/slug/bung/whatever you want to call it would get in the way of a quill stem being inserted. Given a long enough steerer it’d certainly be possible to make it work but I’ve yet to come across that scenario.

Remember you can’t get too close to the crown as the steerer will likely be butted and that will get in the way of the insert and that’s without considering how the steel steerer/ali legs of the Cannondale fork are put together.

I’ve spoken to a retired industrial welder who reckons that the insert is entirely unnecessary, that a properly done butt weld is (at least) as strong as a piece of straight tube and that the insert is a “crutch which supports poor welding and poor alignment” or something like that. As an idea of the level he was at, he was working in nuclear power plants. Not sure that there’s many of us with budgets on par with nuclear power plants to pay for modifications!

Three Mile Island, Chernobyl, Windscale...