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Technical & Reference Section => Tech and Restoration => Topic started by: staple123 on July 31, 2007, 02:47 PM

Title: how do i repair the thread on a 1 piece crank??
Post by: staple123 on July 31, 2007, 02:47 PM

i have a sugino 1 piece which is getting rare but i want to save it, can anybody repair the thread on it ir knows how to'thanks

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: DR VINOAH on July 31, 2007, 02:51 PM

how far gone is the thread?

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: staple123 on July 31, 2007, 02:54 PM

two little threads that is all the rest is perfect!any help? :-\

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: DR VINOAH on July 31, 2007, 03:07 PM

the 2 that are shot
are they on the exposed part?

ie when the whole crank is assenbled on bike
you have a couple of threads showing

if so

i suggest a fine file set
be a tad easy with the filling
you dont really wanna lose much of it
coz you still need the nuts to do up tight

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: staple123 on July 31, 2007, 03:16 PM

yeah , opposite the chainwheel side??if so thats it and i will try that now!cheers

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: Olliecw on August 02, 2007, 11:30 PM

If the thread is well knackerd you can get a heli coil put in there.It basically replaces the thread.Don't know if it will stand the pressure ..It should. I had one done on a brake resevior on my racing kart and that held out under very high pressure..It could be a last resort if all else fails :daumenhoch:
Ollie

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: phantom 19 on August 03, 2007, 06:48 PM

A poper thread file is the answer.

PS you cant helicoil external threads only internal ones. A helicoil is generally stronger than the original thread also.

Title: Re: how do i repair the thread on a 1 piece crank??
Post by: Philbert on August 03, 2007, 11:58 PM

any semi decent machinist or bike shop should be able to sort that out with a 'die' kit in a jiffy! or if you wnted to do it yourself there readily available in places like halfords or any bike shop who deals with shimano (madison) should be able to get a nice park tool kit.