Help! Rounded off Allen bolt stuck!

[Radar]

Re:

Had the same issue with an ultegra crank on my road bike a few years back. Only problem was that my bolt heads were rounding so preemptively I swapped them out for ti bolts. Unfortunately the ti bolts were really poor quality.
Tried the torkx bit, then cutting a slot for a driver. Neither worked, by this time the head was really mashed up. Tried drilling. HSS bits, even with coolant just kept snapping. I even tried putting a bolt in from the wrong side, because if you notice the bolt thread goes all the way through the crank. My idea was that as I tightened the new bolt it would effectively push the other bolt out. This wasn't as daft as it sounds, and was working, but the new bolt snapped off in the crank. Perhaps with plenty of penetrating oil, and a 'slowly slowly catchy monkey' approach rather than 'give it some welly son' this could work.

How did I fix it in the end? Angle grinder. then I bought a new crank and bottom bracket as I enjoyed the angle grinder a bit too much

 

[02gf74]

^^interesting idea but i dont think there is enough thread for a bokt from the othed side.

Not sure how the other bolt can push out without the orinal ddstrying the threads, did you mean it unscrewsa it?

A slot could be made in the bolt end too.

 

[wookiee]

Re:

Wow ok well lots of ideas and thoughts, thanks all for the input... The arm wouldn't come off with 1 bolt out and the end tension cap off so its still on the shaft. On the plus side at least it is still ridable at the moment! Seeing as I want to use it this weekend I may wait until Monday to try the drill out!

 

[02gf74]

Re:

......... and?

 

[wookiee]

Re:

Weeeeellll......the extractor...it didn't work! It didn't grip in the pilot hole I drilled, and just pulled out. I thought about working up in drill bits but I was worried that without a bench drill I would drill at a dodgy angle and f**k up the crank arm! So I ended up cutting the bolt through the slot with a dremel and sacrificing the plastic bit in the slot. This freed up the bolt on the head side and it dropped out, leaving the bolt still in the threaded side of the crank arm. But the arm was off! So I got in touch with Drystonepaul and have sent the crank arm to him to drill out the remainder of the bolt. As I feared my own hamfisted attempts would ruin it! Waiting for it to come back but should all be resolved!

Doug

 

[dyna-ti]

Youre sounding a bit overwhelmed with this so its probably best to find a small engineering firm. It wont cost you much and the job will be done .
I'd be surprised if they want anymore than £20 to do it.
You will have to put up with the long drawn breath through the teeth and the ' Oh who did this' accepting your answer as done by a friend when you both know the truth.
Be prepared to hear sniggering at your back as you walk out

PLUS
Once youve found a small firm who will do 'homers' for beer money you have quite an asset to rely on.

 

[John J]

Good advice

 

[wookiee]

Youre sounding a bit overwhelmed with this so its probably best to find a small engineering firm. It wont cost you much and the job will be done .
I'd be surprised if they want anymore than £20 to do it.
You will have to put up with the long drawn breath through the teeth and the ' Oh who did this' accepting your answer as done by a friend when you both know the truth.
Be prepared to hear sniggering at your back as you walk out

PLUS
Once youve found a small firm who will do 'homers' for beer money you have quite an asset to rely on.

Paul is my "small engineering firm" and he says it is a simple task for him! Hopefully it will come back sorted!

 

[02gf74]

This particular job can be diy at home, thr trick part is to keep the chainset still to prevent the drill from slipling. Anuone with a drill press and vice could do it.

I once did same to remove snapped bolt in kawasaki engine, had a mini drill chuck atteched to a spoke that eas held in a drill in order to clear the frame, the weight of the bike kept the cylinder head still.

PS dont wory about the plastic safety device, if you are concerned, a drop of loctite on the bolt threads will ensure the wont come undone.

 

[drystonepaul]

Re:

Update on this.

Received the crank at the beginning of last week or thereabouts. Left it with some PlusGas soaking for a couple of days while I got on with some other stuff.

Doug had already drilled out most of the bolt so it was just the bolt shaft to remove.

10 minutes with a 2mm drill bit and it was out. All the threads are clean and undamaged.

Doug, you'll need a couple of these to replace your bolts: Part Number = Y1E512100
You can get them here: --> http://www.petracycles.co.uk/search.php ... 00&x=0&y=0
or here: --> http://www.ukbikestore.co.uk/product/39 ... -bolt.html
It's the same bolt as used on Dura Ace cranksets.

The cap diameter on normal M6 button or socket cap bolts is too large for Hollowtech crank arms. The proper replacements are a bit expensive for what they are.

Just need to post it back now.
Doug, please can you PM me your address.