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After a bit of help 🙂
Managed to round off the clamping bolt on the left hand crank of my XT cranks.... As things normally do go from bad to worse for me I don't know why I expected anything different.
The lure if power tools got the better of me and I decided to drill the bolt out. The only slight problem was snapping the drill bit off Inside the crank 🙂
So after I've got the offending drill bit out. That's saying I don't completely muller the crank in doing so would helicoiling it be an option? Never done a helicoil before. Is it ok to do?
Appreciate any help 🙂
You said you rounded the bolt not stripped the thread?
Which model XT?
They are hollow tech 2's.
I rounded the head off and then decided to drunkenly drill it out. Hence the uber stuck/snapped drill bit.
Sometimes I really do exceed myself.....
Can you not wind in one of the reverse thread type things which are the saviour of many a rounded allan key tale? Haven't got a clue what they are called though.
An 'easy out' is what you need
Wish I'd known something like that existed. I've pretty much drilled out the old screw taking the old threads with it and then snapped the bit in for good measure.
Helicoil or a big ugly nut and bolt straight through are the only options then.
I did the same (and I'm sure others have). Standard bolts are made of cheese - I always replace them now with longer stainless bolts.
Will helicoil work in such a small diameter hole?
A helicoil can work, its an M6x1.0 normally isn't it?
the key thing is not to open up the hole tool much now you are attacking it with a drill... much more than about 6.3 - 6.4mm and the helicoil may just strip its way out of the arm, you are essentially drilling and tapping an M7 x 1.0 hole for the helicoil...
Just don't get too drill happy!
Buy a new set of cranks.You've arsed it by two separate processes already......