Ball-end Allen Key Stuck in Bolt

[spartanKid]

:help:

Lesson learned: Don't use ball-end hex keys on even moderate torque settings.

I was trying to change the BB30 bearings on a specialized crank. The two crank arms are held together with an M12 bolt that is recessed inside the driveside arm behind a M5 set screw.

I was trying to loosen the M12 bolt with a 3/8-drive breaker bar and a long, 6 mm ball end allen key socket when the ball-end snapped off and lodged itself inside the bolt head. :eek:

I installed the crank myself and torqued it to spec: 300 in-lbs == 25 ft-lbs = 32 N-m. High-ish torque for most bike parts, but not what I would suspect would break a piece of tool steel. And that's in the range of expected torque for an M12 bolt.

I've tried a bunch of different things to retrieve the ball-end:

Dab of superglue on the end of the broken tool. Bond isn't strong enough to dislodge the ball-end.

Squirt of WD-40, a pin punch and a hammer. Gently tap the corner of the bolt head. Didn't work either.

Cobalt drill bit and an EZ-out. Even the cobalt bit doesn't bite into the tool steel and there isn't a good way to secure the frame into a drill press.

At this point I'm beginning to think I am going to just have to hacksaw one of the arms off and get a new crank. As it is, the M12 bolt inside isn't replaceable so if the hex head inside is too stripped or the ball-end can't be removed the crank is toast anyway.....

[nate2351]

A strong magnet?

[spartanKid]

A strong magnet?

I've thought about this. I need to find a strong one that is less than 8 mm in diameter, unless I want to drill out the threads of the set screw that seals the inside of the crank arm.

[charliedid]

I had that happen on a thomson stem and had to drill it out

[seanile]

I had that happen on a thomson stem and had to drill it out
ditto. had to go at it perpendicularly to cut the bolt in half. those allen heads are made of really hard material.
the magnet won't work on stainless which is what the allen likely is.

maybe drill perpendicularly into the side of the bolt's head if that's exposed enough, so then you can untrap it by flicking it out with something small enough to wedge in behind it if you can expose the broken piece enough. then, youll have to drill the head off, but DO NOT use an ez-out (i didn't heed the advice and it happened exactly as they said it would, at least don't use an easy out with a drill to start, just a screw driver if you must). thomson says not to, so i assume that is advice enough for other things. try what they recommend maybe if you can get the ball-head out?
http://i8.photobucket.com/albums/a10/Zanetti7/tmpbr1.jpg

[Ken Robb]

ditto. had to go at it perpendicularly to cut the bolt in half. those allen heads are made of really hard material.
the magnet won't work on stainless which is what the allen likely is.

But apparently not hard enough--sometimes. :)

[spartanKid]

But apparently not hard enough--sometimes. :)

Oh they're definitely hard enough. They're so hard they're brittle and snap at stress-risers like the neck before the ball end.

Unfortunately on the Spesh crank the bolt head is recessed about 2" inside the driveside arm. It's all but totally in-accessible.

[seanile]

just found this on a forum, pretty neat idea: "Have access to a welder? Just tap the rod of a stick or MIG wire to the reminder of that hex socket and pull out.
You know how when you can't weld, the wire just wants to get stuck in the work piece? This time do that on purpose."

edit: but, if it's super recessed, you're pretty screwed..edit2: unless you can find a pencil grinder and a small carbide burr.

[guyintense]

I've use carbide tipped drill bits to drill holes in tool steel. If you can find one small enough spin at a slow speed and maybe a little coolant.

[kramnnim]

http://www.amazon.com/dp/B00C5KLJ9O?psc=1

These stacked up would be quite strong...

Wonder what is holding it in place?

[spartanKid]

I've use carbide tipped drill bits to drill holes in tool steel. If you can find one small enough spin at a slow speed and maybe a little coolant.

I'm trying to figure out the best way to hold the frame on an end mill to try and cut the ball-end.

[spartanKid]

http://www.amazon.com/dp/B00C5KLJ9O?psc=1

These stacked up would be quite strong...

Wonder what is holding it in place?

Ball-ends are effectively undersized for the spec'd hole they're supposed to grip. The corners of the ball-end are probably wedged against the flats of the socket.

[Tandem Rider]

Have you tried using the smallest pin punch you can get, tapping ballhead inside the corners of the bolthead, against the sides of the bolt, in a "cross" pattern? kind of like the torque pattern on lugnuts. You have to hit it but not too hard. The key is repetition, not driving the pin through the bolt. This has worked for me on similar situations, but it takes a while. Good Luck.

[Peter P.]

Squirt the area with an ENTIRE can of freeze spray. Be sure and wear gloves because the can may get cold.

If you're lucky and the ball end and the mating socket have different rates of contraction, then when they're sufficiently cold you can whack the ball end with a punch and it will free up.

You can get freeze spray at most auto parts stores and some hardware stores.

[lonoeightysix]

along the same lines, use the tip of a soldering iron to heat the bolt head/ball before hitting with the freeze spray.

what brand of hex wrench were you using, for future reference's sake?

[spartanKid]

along the same lines, use the tip of a soldering iron to heat the bolt head/ball before hitting with the freeze spray.

what brand of hex wrench were you using, for future reference's sake?

Kobalt tools from Lowe's. 3/8th drive, long (6") allex key socket.

[Fatty]

along the same lines, use the tip of a soldering iron to heat the bolt head/ball before hitting with the freeze spray.

what brand of hex wrench were you using, for future reference's sake?

It doesn't mater what brand wrench it is , a breaker bar on a ball end.
Not a good idea.

[Fatty]

[QUOTE=spartanKid;1738812]I'm trying to figure out the best way to hold the frame on an end mill to try and cut the ball-end.[/QUOTE

Since the crank is still attached to the frame could you mount an old pedal or pedal spindle to the opposite site and grab that in the vice?
That a some strong hands holding tightly to the frame itself.

[BobbyJones]

If im understanding correctly what you're describing I'd pound in a small chisel first to try and create a groove for a very small bit to find some purchase/bite on the ball head.

Then a little patience and increasingly larger bits.

[wildboar]

Can you pop it out with some compressed air?

[spartanKid]

Thanks everyone for your help. I ended up getting it out with a flat head screwdriver, a hammer, a rubber mallet, and a dental pick.

:banana:

[cmbicycles]

Depending on the version of crank, some S cranks took a torx bit. Sounds like yours maybe did not. Some also have a cap where that set screw goes into... it is glued into the arm, and I've seen those come loose, so it can be done to get the larger bolt out.

Is that cap metal? If so you can put a longer bolt into it to pull on, put mild heat on the cap to loosen the glue and try just pulling that out of the way. If that cap is clearcoated, just take a razor and cut around the edge so it doesn't pull any off the crankarm. Afterwards you should have better access to the larger bolt to get the socket head out or cut/chisel the bolt out.

[seanile]

Thanks everyone for your help. I ended up getting it out with a flat head screwdriver, a hammer, a rubber mallet, and a dental pick.

:banana:

you got lucky if that's all it took

[aosty]

A strong magnet?

:banana:

http://blogs.houstonpress.com/artattack/23533242.jpg

[Vinci]

Squirt the area with an ENTIRE can of freeze spray. Be sure and wear gloves because the can may get cold.

If you're lucky and the ball end and the mating socket have different rates of contraction, then when they're sufficiently cold you can whack the ball end with a punch and it will free up.

You can get freeze spray at most auto parts stores and some hardware stores.
This doesn't apply to the OP, now that he got it out, but I wanted to address this:

This is an excellent want to get stuck bolts out when there is only metal pieces involved. The issue in this case could be that aluminum and carbon may contract at different rates when chilled like that, which could cause an aluminum insert bonded in the carbon to separate and ruin the crank arm.

Just something to consider.

[aosty]

This doesn't apply to the OP, now that he got it out, but I wanted to address this:

This is an excellent want to get stuck bolts out when there is only metal pieces involved. The issue in this case could be that aluminum and carbon may contract at different rates when chilled like that, which could cause an aluminum insert bonded in the carbon to separate and ruin the crank arm.

Just something to consider.

I totally agree.... ya, beware with bonded and composite parts.

[kittytrail]

interesting reads from Bondhus' site: "breakage" (http://www.bondhus.com/features/ballend-breaks/breakage.htm) & "tech" (www.bondhus.com/bondhus_products/Bondhus-Resource-1-13-10.pdf)

most ball ends hex tools are not made for applying much torque, especially box store brands. get better ones*, your bikes deserve it(and you too). :cool:



* no, "bike tools brands" are not the solution there.

[spartanKid]

interesting reads from Bondhus' site: "breakage" (http://www.bondhus.com/features/ballend-breaks/breakage.htm) & "tech" (www.bondhus.com/bondhus_products/Bondhus-Resource-1-13-10.pdf)

most ball ends hex tools are not made for applying much torque, especially box store brands. get better ones*, your bikes deserve it(and you too). :cool:



* no, "bike tools brands" are not the solution there.


Snap-on sells a set of 3/8 drive metric hex keys for $200 :bike:

[cmbicycles]

Snap-on sells a set of 3/8 drive metric hex keys for $200 :bike:
They don't sell them for $200. Snap on is smart, they sell them for only $10 a month... for a few years.

[unterhausen]

Snap-on sells a set of 3/8 drive metric hex keys for $200 :bike:

we can't even find a snap-on dealer that will visit my LBS, so that is out anyway. I would think that you can get a few sizes and be fine, maybe 6mm, 8mm, 10mm
eta: wouldn't impact rated hex wrench do the trick?