Stripped Threads.

[Gert Janse v Rensburg]

Hi Guys .

 

Ive got a customer that came in with a squicky Crank.

Turns out that the Drve side BB was stripped when it was assembled by some previous shop.

It was left like this and given back to the customer to ride as is.

 

No this is where the fun starts.

The Thread is completely Gone. Cant even get it right with the Thread tool. It just goes into the BB housing just touching the sides.

 

Now my Question is.....

Is there anyone that knows if this can be fixed in some sort of way or is the frame gone?

Ive herd that there is a method. Its done by an Engineering shop in Jozie.

Does anyone know where i can get hold of these guys?

[Gert Janse v Rensburg]

Bump....

 

 

Please guys i need a solution for this guy as he doesnt have money to buy a new frame.....

[Reden]

Loctite has a thread repairing compound.

Dont know how exactly it works but might be worth a try.

Try and contact the Loctite supplier them self or Google it on the web.

[Mojoman]

Bike shops...

[Flowta]

Hi Guys .

 

Ive got a customer that came in with a squicky Crank.

Turns out that the Drve side BB was stripped when it was assembled by some previous shop.

It was left like this and given back to the customer to ride as is.

 

No this is where the fun starts.

The Thread is completely Gone. Cant even get it right with the Thread tool. It just goes into the BB housing just touching the sides.

 

Now my Question is.....

Is there anyone that knows if this can be fixed in some sort of way or is the frame gone?

Ive herd that there is a method. Its done by an Engineering shop in Jozie.

Does anyone know where i can get hold of these guys?

 

I've heard with steel frames you could possibly build up enough material in the thread area with welding to be able to cut a thread there. Not sure what the deal is with alumimium, and the need to heat treat the area.

 

Speak to an engineering shop and see what they can do.

[kosmonooit]

Where there is a problem, there is a solution ...

 

One solution would be to mill out the damaged thread and put a custom-turned threaded insert in, bonded or whatever but that a fair amount of machine shop work, easy for an old skool fitter & turner with the right equipment

[TNT1]

Everytime I see this thread pop up in the latest posts widget, I click on it, and it's just never quite what I expect it to be about. Dammit.

[Johan Bornman]

OK, you don't tell us much about the frame but lets assume it is an aluminium frame or, a carbon frame with aluminium BB threaded insert.

 

If it is the latter, the insert can be removed and a new one bonded in place. I've done this on Cervelo and Daccordi.

 

If it is an alu frame, the solution is easy. I assume it is an English thread.

 

An English or ISO BB shell has an ID of 1.37 inches in dia which is approximately 34mm. An Italian BB shell has an ID of 36mm.

 

Simply re-prep the BB as an Italian BB and use Italian BBs henceforth. A framebuilder can help but don't ask me which framebuilders have that tool. Frans du Toit in Cape Town? Don't mill the shell until the machinist has determined the right diameter for the specific Italian thread pitch.

 

You will almost certainly waste your time at an engineering shop. The threading tool will require a guide to keep it parallel with the BB and that is a bicycle-specific tool.

 

If it is a steel frame, the solution is even easier. Braze all along the inside of the BB shell and prep it as if it is a virgin frame.

 

Sell him the new pain job as a feature, not a side-effect.

 

 

Sad to say it will more than likely be cheaper to buy a new frame. However, we don't know what type of frame we're talking about. Don't bother with a cheapie.

 

Good luck