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Getting a sheared bolt out of a seat post clamp

imatfaalimatfaal Posts: 2,716
edited September 2016 in Workshop
Anyone have any protips on how to get the remainder of a bolt out of a seatpost clamp


The head and about 2 turns of thread came off and left the remainder in the clamp

Ok - so I could just buy a new one; but I would prefer not to have to.

And before anyone say it - I was using a torque wrench


  • fat daddyfat daddy Posts: 2,605
    There are 3 techniques I can think of

    (1) .. a fine drill bit and drill into the bolt, get it wedged and hand rotate it out bringing the bolt with you (this only works if the bolt is relatively loose

    (2) very fine screw driver put up against the bol and hammered so it bites in to the metal, then wind out (you will apply shock to the seatpost stem though so might not want to do this too hard if its carbon or alu

    (3) .. attach something very valuable to the seat post clamp that you cannot bare to loose and will only stay there IF the bolt stays there .... then go for a ride ..... you can bet your censored that bolt will come out
  • Since the pressure is now taken off the bolt you may be able to just spin it out with a sharp pick before resorting to drilling anything.
  • I had something similar before, though not on the seat post clamp (think it was a crank arm bolt in my case).

    Depending on where the bolt is sheared off, and whether the threads on the clamp go through both sides ... it may be possible to get the sheared bit of bolt out using another bolt of the same size. Threading this bolt through the side where you can see threads - when it nips up against the sheared bolt the friction should be enough to be able to unscrew it out - it was for me anyway.
  • The RookieThe Rookie Posts: 27,748
    I've had success using a dremel and tile cutter bit, it drills in a short way and then jams and spins the bolt all the way through.
  • pilot_petepilot_pete Posts: 2,108
    Unless you already have the required tools, surely it would just be cheaper to fit a new one...?

  • imatfaalimatfaal Posts: 2,716
    Thanks for the suggestions - none worked so far. Dremel at the weekend
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