9⁄16-inch (14.2875 mm) hole with 20 TPI Tap

ga02clr
ga02clr Posts: 97
edited April 2011 in Workshop
My better half managed to somehow have her pedal undo and fall out while riding at the weekend.

As a result the last 2 or 3 threads in the crank set have been damaged.

I understand I should just need to re-tap these as the rest of the tread is intact and will require a 9⁄16-inch (14.2875 mm) hole with 20 TPI tap.

I have had a search on the internet and this does not appear to be a standard size. Does anyone know where I can get one from or have any experience of doing this?

Thanks a lot.

(I have ordered a replacement crank set but she is racing on Saturday and its possible it won’t arrive in time!)

Comments

  • nicklouse
    nicklouse Posts: 50,675
    any good LBS should have a set of taps

    weldtite do a set of LH and RH for about £45

    or
    http://www.max-t.co.uk/tapsAndDies/20TPIHSS.html

    but you dont say which crank it is.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • sheffsimon
    sheffsimon Posts: 1,282
    ga02clr wrote:
    My better half managed to somehow have her pedal undo and fall out while riding at the weekend.

    As a result the last 2 or 3 threads in the crank set have been damaged.

    I understand I should just need to re-tap these as the rest of the tread is intact and will require a 9⁄16-inch (14.2875 mm) hole with 20 TPI tap.

    I have had a search on the internet and this does not appear to be a standard size. Does anyone know where I can get one from or have any experience of doing this?

    Thanks a lot.

    (I have ordered a replacement crank set but she is racing on Saturday and its possible it won’t arrive in time!)

    Try screwing the pedal in from the back of the crank, using the axle to sort the knacked threads out when its held properly by the good threads at the back of the crank.

    If you know what I mean :)
  • ga02clr
    ga02clr Posts: 97
    Thanks I was going to try that this evening with an old pedal just in case it does not go well!!!
  • Peejay56
    Peejay56 Posts: 41
    Hi ga02clr,
    Try Ceeway - they sell taps (and heli-coil inserts) for both LH and RH crank pedal threads.
    www.ceeway.com
    Check under the section Other Tools

    Pete.
  • ga02clr
    ga02clr Posts: 97
    Its the drive side crank arm that has the damaged thread entry.
  • keef66
    keef66 Posts: 13,123
    +1 on threading a pedal in from the back. Failing that, pop it in to a decent bike shop. They'll have the taps, and it's not the kind of thing you're likely to need more than once so not really worth buying.
  • marcusjb
    marcusjb Posts: 2,412
    Threading from back should work okay - cranks are made of fairly soft metals.

    If it's really borked and your LBS can't do anything, Highpath are apparently the best for repairing cranksets. I've never had to use them myself, but have read nothing but good things about their service.

    http://www.highpath.net/