Has anyone succeeded in taking out a broken bolt from a thumbie mount?

[Prodigal Son]

The threads stripped 2 times on me. While trying a bigger bolt, it broke inside. It´s tight and recessed so maybe finding another mount is the safest bet again losing my mind trying to salvage that thing. It´s the left/ front derr xt thumbie. Anyone w/ a spare, DX, 6sp, 7 sp, suntour ? Anything goes.

 

[ishaw]

I've used easy outs to get stuck bolts out with success. Sounds like you were trying to create a new thread with a bigger bolt, was it a steel or alloy bolt? It can work of course but better to use the right tool for the job, a thread die. Or you could helicoil the damaged thread to repair it and not need a bigger bolt solution.

 

[Prodigal Son]

I've used easy outs to get stuck bolts out with success. Sounds like you were trying to create a new thread with a bigger bolt, was it a steel or alloy bolt? It can work of course but better to use the right tool for the job, a thread die. Or you could helicoil the damaged thread to repair it and not need a bigger bolt solution.

You are right... but i am in a small town in Mexico and did not find machinists around.

 

[RetroDavy]

I've drilled broken bolts out with success before. Getting a smooth face on the broken part, punching a guide in the centre and going slow with a sharp drill bit and oil. Using needle files helps to get the remains of the bolt out without (further) damaging the threads. Not sure how much of this is available to you in Mexico.

I can't quite picture the situation. Is it a thread going into an alloy or steel mount? Can you use a bolt right through with a nut on the back, or is it not open-ended?

 

[Prodigal Son]

I've drilled broken bolts out with success before. Getting a smooth face on the broken part, punching a guide in the centre and going slow with a sharp drill bit and oil. Using needle files helps to get the remains of the bolt out without (further) damaging the threads. Not sure how much of this is available to you in Mexico.

I can't quite picture the situation. Is it a thread going into an alloy or steel mount? Can you use a bolt right through with a nut on the back, or is it not open-ended?

It´s an alloy mount, the XTII 732 or 735 which is known for stripped threads and it´s not open ended.

 

[M-Power]

A fine drill bit at slow speed into the middle of the bolt, then gently hammer a small flathead screwdriver into it until it jams in. Then spray in some WD40 leave for a bit then turn the screwdriver using pliers - often works. Lots of other methods work as above but I always managed to get broken screws out without damaging the main part. You can use progressively larger diameter drill bits to drill most of the screw metal out, then its usually easy to break up the bits in the threads and tip the bits out.

Good luck.

 

[Prodigal Son]

A fine drill bit at slow speed into the middle of the bolt, then gently hammer a small flathead screwdriver into it until it jams in. Then spray in some WD40 leave for a bit then turn the screwdriver using pliers - often works. Lots of other methods work as above but I always managed to get broken screws out without damaging the main part. You can use progressively larger diameter drill bits to drill most of the screw metal out, then its usually easy to break up the bits in the threads and tip the bits out.

Good luck.

Thank you. That´s what i am planning to do.

 

[Prodigal Son]

That´s how i am riding it:

 

[Ryry_1985]

As others have said, totally doable. One word of caution, smaller drill bits tend to break pretty easy and using a pair of pliers (or anything except your other hand) to hold the shifter in place is key! Learned this hard way after a fun Friday evening hospital visit a couple of summers ago. M732 facepalm

 

[Prodigal Son]

I am going for it tomorrow and no, i wont hold the shifter mount w/ my hands.