Removing a sheared bolt - help pls

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Removing a sheared bolt - help pls

10 posts & 8 voices | Started 2 years ago by DT78 | Latest reply from parkesie

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DT78 - Member

Randomly whilst cleaning my bike I heard a sudden ping and the cable bolt on my front mech has sheared off leaving a bit inside the mech.

What tools do I need to buy to get it out?

I've been googling and it would seem I should drill a hole in it and then use a bolt extractor which is reverse threaded...

First question - what size hole should I drill 3mm? (m5 bolt)
Second question - if I buy some of these extractors off ebay how do I turn them? Do I use a rachet or spanner?
Third question - why don't they just jam the bolt in tighter?

Thanks!

Posted 2 years ago #
TandemJeremy - Member

extractors are a reverse thread - so you turn them in the direction you would undo a bolt - they are tapered so wind into the hole you have drilled and then then jam - continue to turn and the bolt undoes.

Is any of the bolt above the surface? Cut a slot in it and use a screwdriver to remove it.

Posted 2 years ago #
Zedsdead - Member

The cutting of a slot is the best option.

If not possible then I just drill out the old bolt.

Posted 2 years ago #
GaVgAs - Member

Its unlikley to be tight,so just tap the bit of thread out with a sharp punch/chisel,you need to tap it anti clockwise to make it turn obviously.

A picture of the problem would help.

Posted 2 years ago #
snowslave - Member

You generally need a powerdrill or power screw driver which you can use in both directions to use the extractors. I use grabbit. Youuse one end to drill the hole out and then switch it around to extract.

Posted 2 years ago #
DT78 - Member

Not a great pic - but the best I can do -

When people say 'just drill it out' do you mean drill it with a smaller hole and then use a reverse thread extractor?

This is what I'm thinking about buying -
http://cgi.ebay.co.uk/EASY-OUT-OUTS-BROKEN-STUD-SCREW-BOLT-EXTRACTOR-SET_W0QQitemZ280449707706QQcmdZViewItemQQptZUK_BOI_Metalworking_Milling_Welding_Metalworking_Supplies_ET?hash=item414c1aeeba

Posted 2 years ago #
boxelder - Member

Try just drilling it. Start with the smallest drill bit you've got and try to get it centred. Once pilot hole is drilled go up through sizes - it should get so thin (what's left) it will come out up the drill. If you have a timber drill (with the sharp, pointy bit for centering)
tap that into the hole you've drilled and turn it out by hand.

Drill slowly!

Posted 2 years ago #
GaVgAs - Member

Looking at your picture you will have to dot punch the end centrally first, then use a small drill to put a hole all the way through the remaining stud/thread.

The revearse taps are ok if the thread is not tight(hardened steel)but on smaller stuff they can snap easily if your not carefull.

The diameter of the bolt is ver small so if you can get the hole in centrally,I would try a small wood screw or bolt first.

Tapping a small Torx bit into the hole has worked in the past as well,getting a good purchase within the hole is key,apply some GT85 and warm it up a bit helps too.

Posted 2 years ago #
singlespeedstu - Member

I bet that'd come out by just getting a seal pick in there and turning the bolt anti clockwise.
Once the head has snapped off there's on pressure holding the bolt shaft in.

The same thing happened the other day on a makes bike and I got the shaft of the bolt out on the trail with nothing more than the screwdriver on my trail tool.

Posted 2 years ago #
parkesie - Member

that looks like it took some of the threads with it.
drill carefully and use an extractor.
Could be a new mech unles you have aold spare and swapp that part over.

Posted 2 years ago #