Thread to ask for help on thread

kelsen
kelsen Posts: 2,003
edited August 2012 in Commuting chat
I managed to get my hands on a set of nearly new pedals, but the thread on the left pedals is slightly mashed where it starts off. I had a quick go at straightening it with a knife but it didn't work and began to strip the thread on the crank when I tried to fit the pedal on.

Any ideas how I can fix the thread on the pedal?

(and yes, I know the left pedal thread is reversed before anyone points it out!)

Comments

  • bails87
    bails87 Posts: 12,998
    Lidl had a tap and die set in at the start of the week, get one of those?!
    MTB/CX

    "As I said last time, it won't happen again."
  • bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!

    +1 Tap and die.
  • kelsen
    kelsen Posts: 2,003
    Aha, great suggestion Bails! Thanks. Never used one in my life so didn't occur to me. Will have to check it out.
  • bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!
    Unless its a pedal thread specific one you wont find a pedal thread in an off-the shelf tap n die set... what you need is one of these but I feel the price might be a bit painful... off to a decent LBS who should have one...
    Invacare Spectra Plus electric wheelchair, max speed 4mph :cry:
  • kelsen
    kelsen Posts: 2,003
    bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!
    Unless its a pedal thread specific one you wont find a pedal thread in an off-the shelf tap n die set... what you need is one of these but I feel the price might be a bit painful... off to a decent LBS who should have one...
    Is that because the thread is reversed? Sorry, I have no idea how these things work.
  • optimisticbiker
    optimisticbiker Posts: 1,657
    edited August 2012
    kelsen wrote:
    bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!
    Unless its a pedal thread specific one you wont find a pedal thread in an off-the shelf tap n die set... what you need is one of these but I feel the price might be a bit painful... off to a decent LBS who should have one...
    Is that because the thread is reversed? Sorry, I have no idea how these things work.
    No its because a pedal thread isnt a standard thread used elsewhere..

    Sheldon says: Most pedals have 9/16" x 20 tpi threads
    However, you can pick up the required die(s) to repair the thread on the pedal from here:

    Right: http://www.rdgtools.co.uk/acatalog/20TP ... HREAD.html

    Left: http://www.rdgtools.co.uk/acatalog/20TP ... _Dies.html

    You'll also need a die holder (to put the die in of course)...

    I don't know where in London you are, but I may be able to help, else your local LBS is the best bet
    Invacare Spectra Plus electric wheelchair, max speed 4mph :cry:
  • bails87
    bails87 Posts: 12,998
    kelsen wrote:
    bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!
    Unless its a pedal thread specific one you wont find a pedal thread in an off-the shelf tap n die set... what you need is one of these but I feel the price might be a bit painful... off to a decent LBS who should have one...
    Is that because the thread is reversed? Sorry, I have no idea how these things work.
    No its because a pedal thread isnt a standard thread used elsewhere..
    Obviously my suggestion required the OP to check that the Lidl thing actually contained the thread type/size he needed.
    MTB/CX

    "As I said last time, it won't happen again."
  • kelsen
    kelsen Posts: 2,003
    I see. Maybe a trip to my local friendly bike shop is easiest.
  • bails87 wrote:
    kelsen wrote:
    bails87 wrote:
    Lidl had a tap and die set in at the start of the week, get one of those?!
    Unless its a pedal thread specific one you wont find a pedal thread in an off-the shelf tap n die set... what you need is one of these but I feel the price might be a bit painful... off to a decent LBS who should have one...
    Is that because the thread is reversed? Sorry, I have no idea how these things work.
    No its because a pedal thread isnt a standard thread used elsewhere..
    Obviously my suggestion required the OP to check that the Lidl thing actually contained the thread type/size he needed.
    Obvious to you and me maybe, not necessarily to those who don't know... :lol:
    Invacare Spectra Plus electric wheelchair, max speed 4mph :cry:
  • veronese68
    veronese68 Posts: 27,768
    You can sometimes save a thread with a small file, or a thread restorer thingy. I'll find a link when on a proper computer rather than the phone.
  • redvee
    redvee Posts: 11,922
    Try screwing the pedal into a steel crank, it might restore the damaged thread. Another option is to file the damage section away.
    I've added a signature to prove it is still possible.
  • Veronese68 wrote:
    You can sometimes save a thread with a small file, or a thread restorer thingy. I'll find a link when on a proper computer rather than the phone.
    redvee wrote:
    Try screwing the pedal into a steel crank, it might restore the damaged thread. Another option is to file the damage section away.
    Both of which can work but with a very fine thread like 20tpi getting it started once you've remove a section of the thread can be really hard and very easy to cross thread after its gone in a couple of turns... A steel pedal thread will always chew up an alumnium crank however much you 'clean it up' so I wouldn't recommend this.

    A forged/hardened steel crank can sometimes act as a die on a softer steel pedal thread, but use some lubrication, grease or light machine oil.
    Invacare Spectra Plus electric wheelchair, max speed 4mph :cry:
  • Fireblade96
    Fireblade96 Posts: 1,123
    It's fecked - you need a new bike ;-)
    Misguided Idealist
  • redvee
    redvee Posts: 11,922
    It's fecked - you need a new bike ;-)

    +1
    I've added a signature to prove it is still possible.
  • veronese68
    veronese68 Posts: 27,768
    This is the thread restorer thingy I meant:
    386-600_1.jpg
    It's a file that has teeth pitched to fit a variety of different thread sizes. So you just use the 20tpi face and it will clean up the thread.