aggst1

Doing some maintenance on my vintage 70s Bianchi and I was checking the crank arms in case they were loose. Well, I was able to tighten both sides (drive and non-drive sides) with some body weight force, and I was starting to worry that they are not getting tight enough for me to stop. I would do a turn on each side just to compare, until the bolt on the crank arm if the non-drive side broke off (see photos). I removed the crank to see better and of course the remainder of the broken bolt is inside the threads of the bottom bracket spindle (see photo). It is a vintage Campagnolo Super Record square taper type.

Any thoughts on how to remove the bolt remains or should I quit kidding myself and buy a new bb spindle?

arex

A machine shop could probably fish that out of there.

Retro Grouch 

You need an EZ out. Tool stores will have them.

The hard part is drilling the right size hole in the shank of the broken screw. The EZ out is a left handed self tapping screw. As you screw it in, it will screw the broken screw shank out.

arex

I didn't suggest that because of the way the bolt is broken off at a fairly steep angle...impossible to drill without sliding off of it and into the spindle's threads.

aggst1

Thanks to both, I guess it is worth trying to drill first, go the EZ out route and see what happens. If it doesn't work I will resort to replacing the spindle.

arex

I was wrong...that's not that steep of an angle. Yeah, try the EZ-Out. Drill slow so the bit doesn't get away from you and into the threads.

seniorchief93

Don't forget to center-punch the bolt prior to drilling to keep it from walking the drill bit.

arex

+1

rpenmanparker 

Everybody loves a challenge so I wouldn't propose to dissuade you, but personally I happen to love the easy way a lot better. I would just get a new spindle. If I had to have use of the part with the broken bolt in it, sure I would give it a try. But that really isn't the case here. Just a divergent opinion to flesh out the options.

Rubato

Ferrous bolt? I've had good luck with solvent and a small magnet. The strain is off the threads and broken studs can often be unscrewed with no difficulty.
If you go with the EZ-out, look at industrial tool dealers for a left handed twist bit-it will often remove the stud without expanding like the EZ-out. Make sure you don't store it where your wife can use it in the "Right" direction!

Crankycrank

Before breaking out the heavy equipment have you just tried spinning the bolt out with a pick or similar? Sometimes bolts are easy to remove without the stress of being tightened down on anything.

Booger1

The bolt is not suppose to be bottomed out,so it should come out with your fingers.......If it is bottomed,use a square ez-out...not a tapered spiraled screw extractor....makes life easier.....won't put so much tension on the bolt.

Make sure the crank arm and BB are NOT flush.....or you'll break the new bolt.

If it's 8mm--5/16....It only needs to be about 15-20 ft/lbs....just tighten until it holds torque after riding around a bit.

fietsbob

Axle is hollow , take out the bolt on the other side and see if you can find a long threaded bolt (or setscrew and allen wrench to fit)

and screw it in from the other side ..

rpenmanparker 

How is that going to push the threaded fragment out the other end? It will just lock up against the residue in the spindle.

fietsbob

Schadenfreude ..

just throwing the idea out brainstorming that kind of stuff..

well then the guy just buys a new BB.. a Phil Or

one of those posh Ones from Compass Bike, should satisfy ..

rpenmanparker 

That's where I would head.

hueyhoolihan

not surprised... if strictly adhered to, will never fail to break one bolt.

i remember my mother cutting my hair and doing the same thing while trimming around the sides. when she eventually finished they still weren't equal but were about two inches above my ears!

BTW, i never gave her another chance.

dedhed

When drilling for easy outs use a left hand drill bit in a reversible drill. This will often spin out the bolt and preclude the need for the easy out (If that name isn't one of the biggest lies around!)

13 Piece Left-Hand Drill Bit Set

Homebrew01

Jam some needle nose pliers or such in there and see if you can unscrew it. Next time, only apply 2 "grunts", not 3.

Andrew R Stewart 

Funny that many crank brands list a 25 to 30 ft/lbs torque for tapered square arms. I do agree with the concept of "only as tight as works". Andy.

Andrew R Stewart 

I think fietsbob meant that you can run a long drill bit through a hollow axle from the other side. As the bit takes a bite on the end of the broken bolt it will unthread the bolt and, hopefully, out the axle end it was threaded into to begin with. The bolt could be trapped in the axle's hollow if run all the way in it too. Some rim glue
would fix it in position then.

As mentioned by others I find the big key to drilling a broken bolt is the start. Andy.

fietsbob

Thnx A.R.S... FWIW, in comparison wit broken end, inside end is flat.. relatively ,.. at least..

davidad

Easy out and a drill. Next time use a torque wrench and never retorque the crank bolt again.

SquidPuppet

And when the EZ-Out breaks off inside the bolt (don't ask) there are shops that specialize in removal. They use a laser to burn out the bolt following the thread line and then they re-tap to clean it up the threads. Pretty amazing to watch. Not cheap.

markjenn

My experiences with things like EZ-outs is highly variable. Keep in mind that a UN55 cartridge BB is about $20 and you'd have a brand new BB.

- Mark