Campy FD helicoil size?

[mudhead]

I have a 2015 Athena 11sp braze on FD with a damaged helicoil. Anyone know what size it is?

[kramnnim]

For the clamp bolt? M5?

[mudhead]

Thx for confirming, not sure if I’ll attempt to address the helicoil or just replace the unit.

[charliedid]

Originally Posted by mudhead

Thx for confirming, not sure if I’ll attempt to address the helicoil or just replace the unit.

Can you post a pic? Are you saying a heli coil has already been installed and it is now stripped?

[oldpotatoe]

Originally Posted by charliedid

Can you post a pic? Are you saying a heli coil has already been installed and it is now stripped?

afaik, it comes as a helicoil from the factory..

[mudhead]

The bike is with my shop now so I don’t have a pick. The helicoil, or threaded insert, was oem. I didn’t notice it when I installed it originally, just when I removed the FD to address poor shifting performance.

[charliedid]

Originally Posted by oldpotatoe

afaik, it comes as a helicoil from the factory..

Ah, now I get it.

TY

[oldpotatoe]

Originally Posted by charliedid

Ah, now I get it.

TY

BUT a 'standard' size..hopefully the LBS has a helicoil 'kit' with the correct size..
Just zing the tool in there to clean up the threads and re-install a new helicoil..
Make sure the old helicoil remnants are not in the hole.

[jc031699]

Originally Posted by oldpotatoe

BUT a 'standard' size..hopefully the LBS has a helicoil 'kit' with the correct size..
Just zing the tool in there to clean up the threads and re-install a new helicoil..
Make sure the old helicoil remnants are not in the hole.

Hmm, I think this was the case with an old 7700 era Ultegra triple FD that I had as well. Long ago, I overtorqued the mounting bolt for attaching the FD to the braze on bracket and pulled out the helicoil. Not knowing if this was original to the FD or not, I drilled and tapped it for a M6 helicoil which ended up working out just fine.


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[dddd]

I had one come in for this issue this week, so I just found me the longest M6 bolt for the combined hole depth and bz-on and washer thicknesses.

I then ran an M6 tap in until it bottomed, then took the bolt and cut one tapping slot into the last few threads at the tip of the bolt and back-and-forth'ed it in real tight.

The hole in the Shimano BZ-on adaptor was ever-so-slightly too small but I just threaded the M6 bolt through it until it stripped out to match the 6mm bolt diameter so it could draw tight freely as the bolt was tightened.

I never did have to use any tap drill since the hole seemed adequately clearanced after I pulled the threaded heli insert all the way out.

I've seen many M5 screws strip out of thin and/or alloy parts and have wished that someone made self-tapping oversized bolts of roughly 5.5mm diameter for such repairs.

An SAE #12 size bolt is one possibility for this but usually has an SAE hex size unless it's 5/32" which is 4mm.

[jc031699]

Originally Posted by dddd

I had one come in for this issue this week, so I just found me the longest M6 bolt for the combined hole depth and bz-on and washer thicknesses.



I then ran an M6 tap in until it bottomed, then took the bolt and cut one tapping slot into the last few threads at the tip of the bolt and back-and-forth'ed it in real tight.



The hole in the Shimano BZ-on adaptor was ever-so-slightly too small but I just threaded the M6 bolt through it until it stripped out to match the 6mm bolt diameter so it could draw tight freely as the bolt was tightened.



I never did have to use any tap drill since the hole seemed adequately clearanced after I pulled the threaded heli insert all the way out.



I've seen many M5 screws strip out of thin and/or alloy parts and have wished that someone made self-tapping oversized bolts of roughly 5.5mm diameter for such repairs.



An SAE #12 size bolt is one possibility for this but usually has an SAE hex size unless it's 5/32" which is 4mm.

Same with the FD braze on adapter and M6 bolt in my experience-


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[charliedid]

Originally Posted by oldpotatoe

BUT a 'standard' size..hopefully the LBS has a helicoil 'kit' with the correct size..
Just zing the tool in there to clean up the threads and re-install a new helicoil..
Make sure the old helicoil remnants are not in the hole.

Right

I guess I forget that some were designed that way with a heli coil.

[jc031699]

Originally Posted by dddd

I had one come in for this issue this week, so I just found me the longest M6 bolt for the combined hole depth and bz-on and washer thicknesses.



I then ran an M6 tap in until it bottomed, then took the bolt and cut one tapping slot into the last few threads at the tip of the bolt and back-and-forth'ed it in real tight.



The hole in the Shimano BZ-on adaptor was ever-so-slightly too small but I just threaded the M6 bolt through it until it stripped out to match the 6mm bolt diameter so it could draw tight freely as the bolt was tightened.



I never did have to use any tap drill since the hole seemed adequately clearanced after I pulled the threaded heli insert all the way out.



I've seen many M5 screws strip out of thin and/or alloy parts and have wished that someone made self-tapping oversized bolts of roughly 5.5mm diameter for such repairs.



An SAE #12 size bolt is one possibility for this but usually has an SAE hex size unless it's 5/32" which is 4mm.

It’s very remarkable and positive (in my eyes) that you did this instead of selling them a new one... yours is a shop that I would give all my money for parts, consumables, and service to after that...



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[dddd]

Home repair shop of sorts, helping out club members, students and the like.

I actually had more than one suitable replacement at hand, but the original mech had apparently been replaced recent, it looked MUCH newer than the old aluminum Trek it had been mounted on and had no slack in the pivots or any damage to the cage.
So I decided to just yank out the steel thread insert and go to a stronger 6mm bolt. The bike's owner was pretty stoked to say the least.

I found the stripped bolt the next day in my driveway, it had fallen free as the bike's owner hauled it to my door. I noticed that the last five or six threads were stripped, so could have been that the bolt needed to be longer (to better sustain whatever previous tightening and working loads had been applied to it). Likely also that the bolt had been severely over-tightened for it's meager M5x.8 threading!