Can a stripped crank removal thread be repaired?

If so, how?
Thanks

I know there's a company (VAR) that makes a thread repair kit - although it doesn't 'repair', it cuts new oversize threads to match a remover that's in the kit.
It costs around £150 I think.

Re:

Alternatively there is a rather brutal tool like a u shaped wedge that you slide between the crank and bb shell then wallop with a hammer that forces Crank off bottom bracket axle. Nothing to do with thread repair but gets cranks off bb axles when ever you need it done. Probably not delicate enough for Crank or frame but an alternative

Re:

Hmm, might wait for a replacement crank arm to show up somewhere. Thanks for info

I have the VAR PE-11000 crank repair kit in my workshop.
Happy to do the job if required.

As Jim suggested, it doesn't restore the existing thread, but cuts a larger one and has a self-extracting bolt along the lines of the Syncros and Sugino Autex things.
So just needs an Allen key (6mm or 8mm IIRC) to remove the crank.


All the best,

Posted this in the other part of the forum

Jonny69":1tb48f7c said:

Not easily because it's a bit of an obscure thread. When I say obscure, I mean it's not a usual common metric size, UNC or UNF etc. Usually to fix stripped threads you'd first try chasing the threads with a plug tap, then either helicoil or drill it out and tap a larger thread. Not really possible in this case because I doubt there's a helicoil in that size (could be wrong though) and the next size up is just another obscure non-standard thread which you then won't have a tool for.

Click to expand...

But I stand corrected danson67

danson67":evtz9ku6 said:

I have the VAR PE-11000 crank repair kit in my workshop.
Happy to do the job if required.

As Jim suggested, it doesn't restore the existing thread, but cuts a larger one and has a self-extracting bolt along the lines of the Syncros and Sugino Autex things.
So just needs an Allen key (6mm or 8mm IIRC) to remove the crank.


All the best,

Click to expand...

Very hard to find this now but a great set from VAR

Jonny69 wrote:
Not easily because it's a bit of an obscure thread. When I say obscure, I mean it's not a usual common metric size, UNC or UNF etc. Usually to fix stripped threads you'd first try chasing the threads with a plug tap, then either helicoil or drill it out and tap a larger thread. Not really possible in this case because I doubt there's a helicoil in that size (could be wrong though) and the next size up is just another obscure non-standard thread which you then won't have a tool for.
But I stand corrected danson67

Click to expand...

You're quite right there.

The standard puller thread is M22 x 1, Metric (extra) Fine....obscure, but not unknown.
I do have a bottoming tap to match that, and would try that before resorting to the VAR kit.
I've never seen a Helicoil in that size, M22 x 1.5 Fine is the closest around...close but no cigar (or puller).

The VAR system is essentially the 'tap larger and helicoil' approach, but with a bike twist:
Remnants of old thread are removed and tapped out to M24 x 1.5 (so works with those really weird, bigger TA and Stronglight threads too).
The special tap and guide system is aligned onto the bolt fitting of the BB axle, so axial with the tapers and axle.
After cutting the thread, the retaining bolt (8mm hex key) is inserted just like a normal crank bolt, then is held captive by a retaining ring screwed into the newly cut M24 thread.



The whole thing works like a Shimano One-Key-Release, Sugino Autex or Syncros auto-extraction bolt.

All the best,

OK. VAR thread repair and auto-extracting bolt fitted.

Old damaged thread bored out on the mill to 22.5mm (for M24 x 1.5 tap).
New thread tapped:

Greased captive bolt inserted with new retaining ring lightly threadlocked.

All clean and ready to go:


All the best,