Anyone knows how to re-tap carbon fibre?

[johnny2007]

I put this in the general diy section, if it's wrong please let me know.
I inherited a carbon fibre bike stem with 2 bolt fixings.
One of them at one point has been overtightened and the bolt doesn't grip anymore.
If it was metal I would simply re-tap one size larger, but what can it be done with carbon fibre?
Is there a metal sleeve that can be used?
If so, where do I find it and what adhesive would I use to fit it?

Thanks

 

[GhostIntMachine]

Not quite the same, I know, but years back we did a project which required bonding layers of carbon fibre into a laminated wooden structure. We used an epoxy adhesive (West System, but I don't recall which glue it was). West System is commonly used in boat repair and they also sell carbon fibre repair tapes. There is also a site called Resin Expert which has a very good page on gluing carbon fibre here that might be useful to you. The resins they recommend aren't readily available in the UK, but West System is, as are cyanoacrylate adhesive (Super Glues)

 

[johnny2007]

Thanks!
I'll get a metal sleeve and glue it to the carbon fibre.
Hopefully it will pass the test of time.

 

[freddiemercurystwin]

 

[johnny2007]

Thanks, but mine is a different situation.
There's no insert there and never was.
Unfortunately previous owner must've cross threaded the stem and now I need a solution.
Nevertheless, good advice on that video.

 

[Old Salt]

They use inserts when 3d printing. You may be able to find one suitable but I wouldn't have a clue which adhesives to use.

 

[mattylad]

What was the thread size of the bolt?
Inserts are available but I'm not sure which or how to fit it without seeing where it's going.

 

[johnny2007]

Thread was M5 but I've seen that to have a female M5 I need to drill an 8mm hole as the sleeve would be M8 male.
So I think I'm gonna go one size smaller M4 female - M6 male.
Bolts for carbon fibre are only torqued at 10Nm on this specific stem, so an M4 would be more than sufficient.