Help! Rounded off Allen bolt stuck!

[bm0p700f]

I would try an stud extractor myself. They have worked for me in the past. If that fails just drill the whole bolt out and do a helicoil reapir of the thread if it gets damaged.

Is it a steel bolt, if so the head may have been rounded because the bolt is seized. This sort of job is just a pain but it is possible to save the cranks.

 

[ted andkilde]

TBH, I'd find a machine shop or a guy who specializes in removing broken or damaged bolts. We have a guy locally who calls himself the "spark plug doctor" who goes out to all the local auto mechanics shops to do onsite extractions, Frank is super reasonable, £15-£50 depending on the complexity of the job and has a huge array of techniques to call on to remove things, he also does it every day so his skills are top shelf.

I like to do stuff myself, but not mangling an XTR crank arm is worth more than my pride

Ask around at your local auto parts place, I'm sure you've got a guy like Frank locally.

Cheers, Ted

 

[wookiee]

I would try an stud extractor myself. They have worked for me in the past. Or just drill the whole bolt out and do a helicoil reapir of the thread.

Stud extractor? Is that the same as the screw extractor?

 

[wookiee]

Is it a steel bolt, if so the head may have been rounded because the bolt is seized. This sort of job is just a pain but it is possible to save the cranks.

Not sure what is made of...chocolate by the state of the head! They were the bolts that came with the cranks...I think I have tightened the bolt beyond the torque recommendations! Could be seized though, maybe some penetrating oil over night too.

 

[wookiee]

Re: Re:

My experience with those screw extractors hasn't been great. With high quality stainless steel bolts found on many bike components the material is a bit too hard for the extractor to 'bite' into them.

They are fine on aluminium alloy bolts and lower grade steel in terms of biting into the bolt and getting enough purchase to unscrew them. You can end up just shearing the bolt cap off.
if you haven't already pre-drilled a nice clean centred hole down the bolt shaft, then it is much more difficult to then get a hole drilled in the end of a broken bolt.
That said, once the bolt cap is gone then the tensile load on the thread will no longer be an issue so the remainder of the bolt shaft usually turns if you can get hold of it.

I'd definitely recommend using that 2mm drill bit first as a fail safe. A bit of light oil on the tip of the drill bit helps too.

You'll be fine Doug. Drilling out titanium bolts on expensive titanium frames is much more nerve wracking.

Another vote for that - I've not had great experience of easy-outs, either. They can sometimes make a bad situation even worse.

I'd be tempted to try and drill it out as has been recommended, here. Just one question - is there space in the gap to use a hacksaw blade to actually cut the bolt, so you could at least get the crank off the spindle? Then it would be easier to drill out when you could put it in a vice or something - or even better, if you've got access to a pillar drill.

Not sure I could get a blade in the gap as its the bolt nearest the frame too. I'm guessing you too have had failures with the extractor method?

 

[wookiee]

TBH, I'd find a machine shop or a guy who specializes in removing broken or damaged bolts. We have a guy locally who calls himself the "spark plug doctor" who goes out to all the local auto mechanics shops to do onsite extractions, Frank is super reasonable, £15-£50 depending on the complexity of the job and has a huge array of techniques to call on to remove things, he also does it every day so his skills are top shelf.

I like to do stuff myself, but not mangling an XTR crank arm is worth more than my pride

Ask around at your local auto parts place, I'm sure you've got a guy like Frank locally.

Cheers, Ted

Thanks for the thought...I'll look into that too

 

[just jacques]

The tried & tested old school way to get that bolt out, you only need a blow torch, butane will do,
a hammer, small cold chisel or punch & some beeswax. Smear the bolt with the beeswax & apply some heat, the beeswax will be drawn down the threads by capillary action & lube the threads, then start tapping the bolt anticlockwise, repeat as necessary.

 

[Rampage]

Re:

See if you can get a hacksaw blade in the slit, Screwfix sell white cheap ones with 0.9mm blade thickness (kerf) IIRC. Make sure the blade when cutting is forcing the bolt to rotate on the loosening direction in-case it helps. Then drill or slot the bolt from the bottom and force something into the hole and remove by screwing it into the crank rather than out.

 

[dyna-ti]

Any chance of a pic visual speaks a thousand words :?

 

[Neil]

Re: Re:

My experience with those screw extractors hasn't been great. With high quality stainless steel bolts found on many bike components the material is a bit too hard for the extractor to 'bite' into them.

They are fine on aluminium alloy bolts and lower grade steel in terms of biting into the bolt and getting enough purchase to unscrew them. You can end up just shearing the bolt cap off.
if you haven't already pre-drilled a nice clean centred hole down the bolt shaft, then it is much more difficult to then get a hole drilled in the end of a broken bolt.
That said, once the bolt cap is gone then the tensile load on the thread will no longer be an issue so the remainder of the bolt shaft usually turns if you can get hold of it.

I'd definitely recommend using that 2mm drill bit first as a fail safe. A bit of light oil on the tip of the drill bit helps too.

You'll be fine Doug. Drilling out titanium bolts on expensive titanium frames is much more nerve wracking.

Another vote for that - I've not had great experience of easy-outs, either. They can sometimes make a bad situation even worse.

I'd be tempted to try and drill it out as has been recommended, here. Just one question - is there space in the gap to use a hacksaw blade to actually cut the bolt, so you could at least get the crank off the spindle? Then it would be easier to drill out when you could put it in a vice or something - or even better, if you've got access to a pillar drill.

Not sure I could get a blade in the gap as its the bolt nearest the frame too. I'm guessing you too have had failures with the extractor method?

Yes, although under the bonnet of a car - but all the same - it failed, and just made it even harder to sort out in the end.

And yes, innocent engine ancilliaries were harmed in the making of this anecdote, and they're not in a happy place recovering from their ordeal. Apparently, aluminium thermostat housings can crack when you whang the feck out of them - who'd have thought it.

Turned a reasonably simple job into and entire fecking nightmare - and this is the thing - I'd read bad things about them before trying it - but thought, nah - it'll be fine...