Rethreading the bolt screw on pedal

sled driver

I've a slight kink on one of the threads of a set of preloved pedals that I picked up during the week.

It slightly distorted the crank threading when I tried to fit it last night. I got that problem ironed out in the LBS last night with a tap wrench and I've been able to put the old pedal back on.

However, he didn't have the tool to sort out the kink on the threading of the pedal. He reckoned a car/motorbike repair garage would be my best bet.

Anyone any experience with this problenm before of know of an alternative LBS that would sort it out?

Before anyone goes off on a tangent, yes I know about the reverse threading on the non drive side etc. Besides, that's not the problem, it's the drive side pedal that's I've the issue with.

lennymc

sounds like you need a dye to clean up the threads? local engineering firm should be able to do that for you.

munsterleinster

You're looking for a 9/16 x 20TPI die...
Can't see a car or motorbike repairer having this.

I've German and Japanese motorbikes and they'd have nothing in this size (So that leaves some old English or American stuff)
Most likely same for cars..

If you have any friends in Bolton street college, I'd suggest getting them to bring in the pedal and ask the stores guy if he'd have that size.

You could just walk in and ask them yourself.. If they don't have it, I don't think anyone will.

macnab

I would clean it up with a triangular file if I couldnt locate a die, taking care to only remove the offending material.

nilhg

Ebay is great for stuff like this, €16 might be more then the OP would like to spend on the pedals but nice to know they could be sorted.

Lumen

I would recommend a threading chisel. It's just like a normal chisel except you use it to knock back threads into line.

macnab

Lumen you just reminded me that I used to have a thread file in my toolbox at some stage, a handy tool if you can find one. Each of the 4 sides on each end had a thread profile cut into it, i.e. 8 thread types per file.

sled driver

Thanks for the input guys. It never ceases to amaze me, the fountain of knowledge of the cycling forum posters.

@ lennymc/munsterleinster - Spot on, spoke to a guy in a motorbike repair garage at lunchtime. He uses metric now and reckons I need someone dealing with old english stuff or alternatively an engineering firm may be able to sort it.

@macnab - This seems to be the simplist option for now and see how I get on. I don't think the kink is too bad so a bit of filing might sort it. Any idea where you picked up that thread file?

@ lumen - first I thought this "threading chisel" was something that I would need to go and get a "long stand" to use but I see what you mean after a bit of research.

@ nilhg - great, thanks for that link. If it comes to it, I'll pick up one of those bad boys.

I'm actually surprised though that LBS weren't equipped for this type of thing, I can't imagine it's that rare a problem? Although, I suppose it's cheaper to sort the crank out and buy new pedals than the other way around.

piston

Remember pedals have left and right hand threads. The Ebay link will only work for the right hand pedal.

sled driver

Ya got that Piston, thanks. It's the drive side pedal I'm having the issue with anyway.

el Bastardo

sled driver wrote: »

I'm actually surprised though that LBS weren't equipped for this type of thing, I can't imagine it's that rare a problem? Although, I suppose it's cheaper to sort the crank out and buy new pedals than the other way around.

So you say, but I still don't know what a 'kinked' thread is (and I'm a mechanical engineer with plenty of shop floor experience in turning, cutting, sawing etc...).

sled driver

Apologies for my non-mechanical engineering language.

There is some flaw on the thread, a weakened thread perhaps, that is impeding the screwing operation into the crank, or in lay mans terms..... It appears that a couple of the threads on the pedal are slightly fcuked. Hows that ??

The threading looks fine at first glance, but there seems to be a very small indentation running perpendicular to a couple of the threads, which I can only assume is the reason for the difficulties in screwing into the crank. As I didn't want to force it and make st1t outta the crank, I stopped.

el Bastardo

If it were my pedals, I would ignore the 'blip' in the thread - You won't fck anything up majorly.

Holyboy

@sled driver, it's very uncommon to get a damaged pedal thread as most of them are hardened steel and the rest Ti, filing may work or you could always replace the whole axle (this is not a job I have been very found of in the past so haven't done it in many a year!!)