Crank arm pinch bolt

[Honkdonk]

I have a slight issue in that one of the two crank arm pinch bolts has a rounded head and I need to get the crank out to replace the BB. So with a rounded head I and my LBS cant get it out..

 

The bolt takes a 5mm allen key and is countersunk so I cant cut into it without causing major damage to the crank arm - its an XT crank with a 34t ring

 

Any ideas?

[fanievb]

I managed to moer a slightly smaller torx bit (can't remember the size) in the rounded head and remove it. remember to replace the other bolt and loosen both simultaneously/equally.

 

if that fails a lot of patience and a 4mm drill bit.

 

[JanJan]

Would you be able to fit a steel saw blade into the gap? Because then you would be able to cut off the bolt to remove the crank arm. You can then take the loose arm to a machining shop to drill and counter thread the bolt to remove it.

[Formallyknownas]

Easy out

Have you got bud? I've got a brake set that I bought as a bundle with a stripped allen head.

I'll gladly pay with a sixer of your preference.

[HowardSteele]

Once you've tried the torx bit trick if you still stuck

do it the proper way drill a hole and use an easy out.

Midas sells a Easy out set for under R100

[Skinnyone]

Carefull application of a SHARP drill and drill the head off...done it before...

[droo]

EZ-Out or Grabit. It's the right tool for the job. Drill hole, remove bolt. Job done.

 

The hacksaw and screwdriver trick should not be employed in a professional workshop unless there are serious extenuating circumstances (in my humble opinion, of course...)

[droo]

Cost me almost nothing and they've saved my ass countless times

 

Do yourself a favour - make yourself some aluminium jaws for your vice. They will change your life for about 20 bucks and an hour of graft.

[V12man]

I have a slight issue in that one of the two crank arm pinch bolts has a rounded head and I need to get the crank out to replace the BB. So with a rounded head I and my LBS cant get it out..

 

The bolt takes a 5mm allen key and is countersunk so I cant cut into it without causing major damage to the crank arm - its an XT crank with a 34t ring

 

Any ideas?

Change your LBS...

[droo]

That vice is older than i am 

 

No issues with million year old tools, I have a few. But steel jaws near a bicycle make my nuts tighten a bit.

[Honkdonk]

Change your LBS...

Dunno hey.. I take Anton's word for it if **** gets real

[Honkdonk]

Easy out 

Even for a countersunk crank arm pinch bolt? Do they make EZ Out in that size?

[V12man]

Dunno hey.. I take Anton's word for it if **** gets real

 

There are a couple.of ways of removing that in the order I would try:

 

Left handed drill

Bolt remover - like a fine splined torx wrench designed to be hammered into a round hole

Easy out - these are a bugger if they break - so make sure you get a high quality set

Dremel to cut screwdriver slots and use an impact wrench to undo it with a screwdriver bit.

Build it up with a tig welder - this I would get my engineering mate to do

Use a spark eroded to remove the remnants of the above- hard to do because that is still attached to the frame and I am not sure if it would all fit under the only spark eroder I know of.

[Honkdonk]

 

There are a couple.of ways of removing that in the order I would try:

 

Left handed drill

Bolt remover - like a fine splined torx wrench designed to be hammered into a round hole

Easy out - these are a bugger if they break - so make sure you get a high quality set

Dremel to cut screwdriver slots and use an impact wrench to undo it with a screwdriver bit.

Build it up with a tig welder - this I would get my engineering mate to do

Use a spark eroded to remove the remnants of the above- hard to do because that is still attached to the frame and I am not sure if it would all fit under the only spark eroder I know of.

I am going to asses the situation with him on Friday..

 

Damn it man. Last thing I need.

[Eugene Brown]

 

There are a couple.of ways of removing that in the order I would try:

 

Left handed drill

Bolt remover - like a fine splined torx wrench designed to be hammered into a round hole

Easy out - these are a bugger if they break - so make sure you get a high quality set

Dremel to cut screwdriver slots and use an impact wrench to undo it with a screwdriver bit.

Build it up with a tig welder - this I would get my engineering mate to do

Use a spark eroded to remove the remnants of the above- hard to do because that is still attached to the frame and I am not sure if it would all fit under the only spark eroder I know of.

Soak hole overnight with penetrating oil. Drill 2, then 2.5, then 3, then 3.5mm holes through bolt head, and use easy out slowly, the same way you would a tap i.e loosen out a bit, run forward a bit, loosen out a bit, run forward a bit until bolt is free. That would be the most extreme, normally just drill 2.5mm hole and easy out (even with Midas quality-level easy outs)

Worked for me over many years on aircraft, bicycles, forklifts and earth moving equipment, so you should be OK.

[V12man]

I am going to asses the situation with him on Friday..

 

Damn it man. Last thing I need.

Not as bad as my mate who stripped the splines on his XTR crank because that Bolt was not fastened properly... it is fixable but not economically sensible to fix it...

 

I can help you with the first 4 or so... then point you at a couple of specialists if you get stuck beyond that.