Stripped bottom bracket threads -solutions please

[paton]

https://veloretrocourse.proboards.com/thread/488/edco
https://fr.der-ritzler.de/products/edco-grip-innenlager-bsa
Its possible that it is not a universal fit: it has to be a close fit suited to each thread/ BB size

http://i75.servimg.com/u/f75/09/00/90/77/p23_ed10.jpg

 

[paton]

https://i.ebayimg.com/images/g/d~8AAOSwLalh6cFs/s-l960.jpg

 

[crimin]

Depending on how bad it is, and how much you value the frame:

The Loctite Form-a-thread kit (#28654, or PC 3967) is a good basic thread repair system, and should be OK for a large diameter, low load fine thread like a BB shell. You spray a release compound on the male thread (cup), and a cleaner/primer on the female thread (BB shell), then mix and apply the epoxy into the thread and assemble. The release compound allows the cup to still be screwed out as normal.

I also have the 45° cutting tool for putting the appropriate chamfer on the BB faces if you're going down the threadless BB route, such as Mavic YST, or M-wave.

A quick and nasty repair (only for frames that you're not too attached to, probably) is to take a 2-3 mm straight cut across the underside of the BB shell. Close up the shell with a combination of brute force and heating, then weld or braze up the gap, then retap the threade into the fresh metal of the now slightly smaller diameter shell.

As @Peachy! mentioned above, I have repaired several BB shells by reaming out the old thread to a larger diameter, tapping out to Italian spec,

View attachment 598535

then fitting a pair of thread repair helicoils.

View attachment 598534

These are steel inserts that are screwed into the Italian thread, held in with Loctite 638 Retainer, with a standard BSA thread on the inside.
This is the best way to sort it out.

PM for more details if you're interested.

View attachment 598536

All the best,

Depending on how bad it is, and how much you value the frame:

The Loctite Form-a-thread kit (#28654, or PC 3967) is a good basic thread repair system, and should be OK for a large diameter, low load fine thread like a BB shell. You spray a release compound on the male thread (cup), and a cleaner/primer on the female thread (BB shell), then mix and apply the epoxy into the thread and assemble. The release compound allows the cup to still be screwed out as normal.

I also have the 45° cutting tool for putting the appropriate chamfer on the BB faces if you're going down the threadless BB route, such as Mavic YST, or M-wave.

A quick and nasty repair (only for frames that you're not too attached to, probably) is to take a 2-3 mm straight cut across the underside of the BB shell. Close up the shell with a combination of brute force and heating, then weld or braze up the gap, then retap the threade into the fresh metal of the now slightly smaller diameter shell.

As @Peachy! mentioned above, I have repaired several BB shells by reaming out the old thread to a larger diameter, tapping out to Italian spec,

View attachment 598535

then fitting a pair of thread repair helicoils.

View attachment 598534

These are steel inserts that are screwed into the Italian thread, held in with Loctite 638 Retainer, with a standard BSA thread on the inside.
This is the best way to sort it out.

PM for more details if you're interested.

View attachment 598536

All the best,

Hi are you still fixing bb as I have a job for you. Thanks Anthony

 

[Old Ned]

Did the frame ever get 'passed on' to someone? If I'd seen this at the time I'd probably have made an offer.

 

[danson67]

Hi are you still fixing bb as I have a job for you. Thanks Anthony

Yes, still here doing the repairs and such.
PM me (Click my name to go to my profile page, then 'Start Conversation'), and we can go from there.

All the best,

 

[minutemat]

Hi @danson67, I found this page through google. Damaged my BSA threaded shimano bottom bracket racing down Cadair Idris, and was told by my LBS that it is impossible to fit a threaded bb cup with the damage there is now. I quite like this bike, and don't really feel like getting a new one unnecessarily.

Do you think this Loctite Threadlocker will do the trick? I'm based in Shropshire, not far from you, so happy to drop it over if you think you could work a bit of magic.

Tried PM but perhaps as my profile is new I cant see the option to 'start conversation'.

mathew (dot) hocking (at) gmail.com

Cheers

 

[Nabeaquam]

Hi @danson67, I found this page through google. Damaged my BSA threaded shimano bottom bracket racing down Cadair Idris, and was told by my LBS that it is impossible to fit a threaded bb cup with the damage there is now. I quite like this bike, and don't really feel like getting a new one unnecessarily.

Do you think this Loctite Threadlocker will do the trick? I'm based in Shropshire, not far from you, so happy to drop it over if you think you could work a bit of magic.

Tried PM but perhaps as my profile is new I cant see the option to 'start conversation'.

mathew (dot) hocking (at) gmail.com

Cheers

View attachment 876180
View attachment 876179

You can try red Loctite. If it doesn’t hold or if you want to remove it a propane torch will usually free the loctite. Personally, I’d try JB Weld reinforced epoxy, if it’s unavailable in the UK, then order it on Amazon. It’s the strongest glue for most applications except plastic, and it’s still good for that. It works for loose headset races and doesn’t give out. I’m pretty sure this would work for you. It comes out on top, by a lot, in independent tests among glues.

 

[minutemat]

You can try red Loctite. If it doesn’t hold or if you want to remove it a propane torch will usually free the loctite. Personally, I’d try JB Weld reinforced epoxy, if it’s unavailable in the UK, then order it on Amazon. It’s the strongest glue for most applications except plastic, and it’s still good for that. It works for loose headset races and doesn’t give out. I’m pretty sure this would work for you. It comes out on top, by a lot, in independent tests among glues.View attachment 876207

Hiya, it looks like the thread has worn too much for this trick. I've managed to persuade @danson67 to have a look at it, think he will insert an Italian thread. Thanks anyway!

 

[danson67]

Hiya, it looks like the thread has worn too much for this trick. I've managed to persuade @danson67 to have a look at it, think he will insert an Italian thread. Thanks anyway!

It gets reamed out then tapped up to Italian, but then the bonded insert takes the thread back down to BSA as before.
Actually having an Italian thread BB would be a huge PITA these days.

All the best,

 

[stephan]

Hiya, it looks like the thread has worn too much for this trick. I've managed to persuade @danson67 to have a look at it, think he will insert an Italian thread. Thanks anyway!

Interesting thread this (pardon the punt), I would like to see that getting done with the tools used, also where you get the parts/inserts from. I hope it all works out ok. Cheers, Stephan. @danson67 @minutemat