Viewing 40 posts - 1 through 40 (of 53 total)
  • Removing a REALLY stuck Square taper crank – HTF
  • iamanobody
    Free Member

    So far i have managed to remove the nds
    The drive side has had:
    crank extractor snap
    new one out out threads
    Drill
    Angle grinder but not made much head way – better discs? if so what?
    Ball joint splitter
    Bigger hammer

    Really struggling here – any more ideas?

    the-muffin-man
    Full Member

    Gear Puller.

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    dovebiker
    Full Member

    I have a cold chisel of the right thickness/angle to fit between BB cup and crank arm and a 4lb club hammer.

    In bike shop, angle grinder to cut 2 slots in end of arm – assuming its scrap

    mashr
    Full Member

    Ball joint splitter plus heat – not the forked hammer type

    The forked hammer type absolutely does the job too, plus you get to hit stuff

    iamanobody
    Free Member

    with the cold chisel am i going in perpendicular to the crank? if so thats how ive used the ball joint splitter to no avail
    angle grinder had a new disc when i started but not cutting great. What discs are best to cut into the metal?

    alexnharvey
    Free Member

    If you’re using an angle grinder buy a thin, metal cutting disc (rather than a grinding disc) and wear eye protection.

    Can you get some penetrating oil on the frame side of the taper? Have you tried putting the other crank back on and taking it for a careful ride so that pedalling forces loosen it?

    Aluminium expands more than steel so that should be very helpful in loosening it too.

    StirlingCrispin
    Full Member

    Are you turning it the right way?
    Over the top to the front.

    You also want a socket holder and a breaker bar (I use a Trailgator – only thing it is good for)

    https://pedros.com/products/tools/pedal-crank-and-bottom-bracket/bb-socket-holder/

    iamanobody
    Free Member

    there is no thread left – it pulled out – the cranks been on for >20 years

    iamanobody
    Free Member
    submarined
    Free Member

    If you are not managing to cut through an alloy crank with a grinder, have you made the mistake of accidentally using a child’s Bob The Builder grinder?

    Cut a slot along the axis of the axle, whack a chisel into the slot, and the crank will pop right off (if it hasn’t already with just the slot cutting)

    Edit: just seen the picture. Jebus. Use a cutting disc. Lop the spider arms off first if access is tricky.
    Also give it some taps towards and away from the frame to try and lever it off.

    iamanobody
    Free Member

    alloy or alu?

    andyeez
    Free Member

    Hacksaw worked a treat on mine, 2 slots 10mm apart as near to the axel as poss then drive out the bit in the middle with a hammer and chisel…

    DezB
    Free Member

    Looks to me like it’s still held onto the axle with the bolt:

    So ain’t no pulling getting that off!

    Merak
    Full Member

    Cut the spindle.

    Merak
    Full Member

    Hope the BB isn’t seized.

    They are a real pig if dry assembled.

    Hateful design. I love outboard bearings for this reason.

    Bon chance.

    TiRed
    Full Member

    Cut the spindle.

    This. Get a decent full-size hacksaw and a sharp new blade. Cut it off behind the chainset. Then go for the BB with penatrating oil 😀

    I’d probably remove rings and what else I could to improve access. Then clamp the spider to a tube with a toestrap or (modern) big zip tie).

    DezB
    Free Member

    Cut the spindle

    I think he was asking what will cut it.

    iamanobody
    Free Member

    dezb – DEFFO no bolt in there buddy!! That is what is left of the axle!!

    iamanobody
    Free Member

    Hacksaw is not touching it with a new blade in!!

    DezB
    Free Member

    Then [p]ray for the BB

    See, this is the thing – you go through all this and find that you can’t get the BB out of the frame anyway. So have to trash the frame. Been there, done that.
    The splines on an old BB just aren’t grippy enough to remove a seized one.

    I’m betting this is a job you offered to do for a friend 😆

    Merak
    Full Member

    Hacksaw won’t cut it.

    As mentioned a spanking new metal cutting disc in a grinder right through your spindle, after you’ve cut the rings away with same.

    iamanobody
    Free Member

    ONly positive is that the NDS cup came out easily as was plastic. SO at least penetrating oil/plusgas MAY get into the drive side threads?

    DezB
    Free Member

    DEFFO no bolt in there buddy!! That is what is left of the axle!!

    Oh wow. Maybe it’d pull off then! I stand by what I said about the BB though 😀

    nuke
    Full Member

    Use to go for a ride sans bolts to get cranks loosened off but that door is closed given the chopped chainrings

    nixie
    Full Member

    Hacksaw should go through the axle. Had an octalink BB off that way before.

    the-muffin-man
    Full Member

    Looking at that pic I’d just get an angle grinder on that now and stop faffing about with a hacksaw!

    Chop it up and sell as ‘mint’ on eBay! 🙂

    iamanobody
    Free Member

    Will someone please link to a suitable cutting disc that is 22.2 diameter

    submarined
    Free Member

    I’m guessing you’ve got a standard 4.5″ grinder? If so, https://www.screwfix.com/p/metal-cutting-disc-4-115mm-x-1-x-22-2mm-5-pack/2585v

    Bur please please please also wear at the very least goggles and gloves. Better still a visor. Cutting discs can be relatively easy to snap, and when they do, can cause a lot of damage.

    swedishmetal
    Free Member

    See, this is the thing – you go through all this and find that you can’t get the BB out of the frame anyway. So have to trash the frame. Been there, done that.

    I’ve restored countless old bikes and never been beaten by a crank or bottom bracket. The biggest tip is to only break out the hacksaw or grinder when all other engineering solutions have failed.

    I once removed a cup and cone BB out of a 25 year old bike which had been sitting outside for several years. This needed a 36mm (IIRC might have been a 32mm) headset spanner on the flats to remove the fixed cup on the drive side. It kept slipping off so I clamped the spanner to the cup using threaded bar and some huge washers and metal plates. Then with a 1m long extension on the spanner it eventually cracked off. Took a while to unwind it from there but the crack was the rust bond separating.

    The best way to remove sq taper cranks is to ride them around without the bolts on – soon comes off!

    jkomo
    Full Member

    I had a similar problem with a campy bb.
    My mate welded a long bar to it and it wound out easily.

    DezB
    Free Member

    Let’s hope he knows if it’s Italian or English thread.. 😉

    thisisnotaspoon
    Free Member

    Let’s hope he knows if it’s Italian or English thread.. 😉

    Shouldn’t matter (I think?) the cartridge side is always the same, just the spacer is different?

    philjunior
    Free Member

    I removed one no problem with an angle grinder, just metal discs from B&Q or those that came with it (lidl special) I think.

    Just cut down level with one face of the sq taper. Try not to cut al. and steel with the same disc as it can cause fire (probably not an issue in a home workshop but if you had a load of swarf from other stuff it could be.) – think thermite reaction.

    It looks like you’ve been grinding all over the place, not keeping it focussed on making one cut that will do the job.

    In terms of the BB, hopefully its steel shell/steel frame, or alu shell/alu frame, then it should come out without much bother. You can clamp the BB tool in the vice and rotate the frame around it which gives you a lot of torque – and soak in plusgas for a while first to make it as easy as possible before you break any tools or fittings for tools.

    epicyclo
    Full Member

    swedishmetal

    The best way to remove sq taper cranks is to ride them around without the bolts on – soon comes off!

    This. Maybe pad your toptube. 🙂

    Too late now though.

    Amazing how many people don’t know this.

    joebristol
    Full Member

    Looks a mess. I’ve not had this before but I’d cut away as much of the spider arms holding the chainring on as possible to give you better access to the metal round the bb spindle. You should then be able to cut downwards on it and get it split in half.

    I’m assuming if it’s a small grinder it’ll be 4.5” – some cutting discs from b & q will do the job.

    I echo the safety gear comments – definitely wear goggles at the minimum.

    When it comes to the bb I’d soak it with penetrating oil for a few days before having a go at it. The last one I had wasn’t moving dry, but having sprayed it numerous times with penetrating oil over a few days it then cracked off ok. Replaced with gxp external bearing bb!

    madhouse
    Full Member

    I had this issue with the boy’s bike, handily the old crank was aluminium so a hacksaw went through it with easy, after that a chisel to crack it past the BB spindle and it was off.

    Square tapers are evil.

    brant
    Free Member

    As an alternative, if the NDS is out I would be tempted to try using a punch/chisel on the axle, driving it into the shell, supporting the crank on the outside of the shell.

Viewing 40 posts - 1 through 40 (of 53 total)

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