Classic & Vintage - Can I rethread a crankarm?

I bought a sweet chrome Ross Mt Something or other and I got it cheap because the BB is shot and the guy had stripped the non drive side crankarm so it couldn't be removed. I bought, got it removed with a pickle fork and now am wondering if I can fix the crankarm. The crankset is a nice Sakae triple that looks sharp, so I'd like to use it again once I replace the BB with a cartridge Can I re-tap it?

I doubt that you can re-thread it, but why not use it anyway and remove it the same way when you need to replace the BB? Presumably that won't be anytime soon.

I think French crank threads are a little bigger than English, so maybe you could tap it out to French. Of course, then you need a French crank extractor.

I don't think it's worth rethreading. Just use as is and buy a cheap Harbor Freight pitman arm or tie rod remover.
They are threaded and less damaging than a pickle fork.

Yes, the crank arm can be rethreaded oversize and most old bicycle shops will have the tap to do the job. The question is is it worth it? My guess is they will charge more than a new/used one will cost. But that is just a guess.

I don't think it's worth rethreading. Just use as is and buy a cheap Harbor Freight pitman arm or tie rod remover.
They are threaded and less damaging than a pickle fork.

Also someone the other day mentioned using a taper-fit drill chuck removal wedge.

btw I just looked at the HF tool mentioned above and the first 4 reviewers all complained of it breaking. I guess you get what you pay for.

I'm thinking I'll just reuse the arm with the new bottom bracket - I don't see myself removing it a lot.

Also someone the other day mentioned using a taper-fit drill chuck removal wedge.:thumb:

btw I just looked at the HF tool mentioned above and the first 4 reviewers all complained of it breaking. I guess you get what you pay for.

http://www.drillspot.com/products/947099/jacobs_chuck_1503-13268_repr_jacobs_13268_3_wedge_set


http://images.drillspot.com/pimages/9834/983495_300.jpg

Yes, the crank arm can be rethreaded oversize and most old bicycle shops will have the tap to do the job.

Who makes a tap for this? No LBS I've asked has one. I've asked because I recently stripped the NDS threads of a beautiful Ofmega Mistral crank; made me sick. I figured I'd just borrow a gear puller and that's the way it'll have to come off again should it need to.

You can use a 'heli-coil insert to replace the existing thread.

From the website: "Heli-Coil inserts are precision-formed screw thread coils of extremely hard diamond-shaped 304 stainless steel wire. When installed into Heli-Coil tapped holes, screw thread inserts provide permanent conventional 60° internal screw threads that accommodate any standard bolt or screw."

http://www.emhart.com/brands/heli-coil

Who makes a tap for this? No LBS I've asked has one. I've asked because I recently stripped the NDS threads of a beautiful Ofmega Mistral crank; made me sick. I figured I'd just borrow a gear puller and that's the way it'll have to come off again should it need to.

VAR makes a tool for this:

http://www.os2.dhs.org/~john/var-crank.jpg

I tried a Bicycle Research tool (http://www.amazon.com/Bicycle-Research-Crank-Thread-Chaser/dp/B001PTALQ8). It's not quite a tap but it has a guide like the VAR tool shown. It wasn't happening.

I tried a Bicycle Research tool (http://www.amazon.com/Bicycle-Research-Crank-Thread-Chaser/dp/B001PTALQ8). It's not quite a tap but it has a guide like the VAR tool shown. It wasn't happening.

As you are no doubt now aware, the crank threads on
the spindle socket present some unique problems in
the rethreading process. It's a pretty shallow, flat
bottomed hole, so you cannot just take a standard
tapered tap and run the sucker through.

I've never attempted this myself, so can offer no guidance
or suggestions, other than I really do not think it would
be a very good spot to try a helicoil either.

The jacobs chuck thingies seem to work reasonably well
once you get the hang of it, and as has been mentioned,
you really do not have to pull the cranks all that often
if they've been serviced and installed correctly.

VAR makes a tool for this

I swear I've heard that before.

JA Stein makes a "system" that removes a stripped-out crank arm, a special tap that cuts new over-sized threads, and the replacement one-key remover caps to re-install the arm(s)...it costs $150 and I bet your LBS doesn't have it.

Yes... you can re-tap it but bet that finding a replacement arm to match would be far easier and cheaper.

What crank is it and how long are the cranks ?

JA Stein makes a "system" that removes a stripped-out crank arm, a special tap that cuts new over-sized threads, and the replacement one-key remover caps to re-install the arm(s)...it costs $150 and I bet your LBS doesn't have it.

and then what happens when you strip the the new oversized thread ;)

It is a Sakae CR set in 175 mm. I just need a non drive side if someone has one.

I did try a gear puller, and the one I have has a pointy tip on the screw in part, so it wouldn't stay in the right spot on the spindle.

I read your question and some of the replys. In my experience we would sometimes get away with chasing the threads, but retapping is near impossible. I don't like using an imappropriate tool if at all possible and no one intends to remove anything in the near future. That said, why not just replace it, you can buy a new one really inexpensively from any of the on line dealers. I have seen them for under ten dollars.

Who makes a tap for this? No LBS I've asked has one.

At the moment, I have no idea, however the local vintage bicycle guru who has worked at a local bike shop since the Earth's crust showed me the kit and commented that in a quarter of a century, he had used it only a couple of times.

If I ever get around to it, I will ask the guy who makes the tap kit and where one can be purchased. Chances are they are no longer available but that is just a guess, on my part.

Buy a new one. I have a few of these cranksets. Lol. :D

I used the bicycle research tool on a sakae crank like this too, but it is made more for dustcap threading than doing all the threads deep into a crank, I think they even call it a dustcap thread chaser, but I was lucky that my crank had mostly the top threads damaged. I bought the tool and donated it to a local co-op and we've used it there a couple of times... go slow, use lots of oil, be careful, etc. But the tool is likely as much as a new arm... especially if the rethreading doesn't work for you. At the co-op we usually just remove the stripped with the ball joint separator mentioned above.

If you have a crankset like this (or multiples) for cheap, I'm interested for sure. PM me.

You can use a 'heli-coil insert to replace the existing thread.

From the website: "Heli-Coil inserts are precision-formed screw thread coils of extremely hard diamond-shaped 304 stainless steel wire. When installed into Heli-Coil tapped holes, screw thread inserts provide permanent conventional 60° internal screw threads that accommodate any standard bolt or screw."

http://www.emhart.com/brands/heli-coil
^ this +1. I just had a crank arm (the drive side/chainring arm) fitted with a helicoil at my local Performance bike shop. It cost me $20 but saved an otherwise destroyed vintage crankset.

If you have a crankset like this (or multiples) for cheap, I'm interested for sure. PM me.

Sure. Yours for the cost of a Raleigh International. ;)

Sure. Yours for the cost of a Raleigh International. ;) I get those cheap, so no sweat.

For reference (http://www.flickr.com/photos/27683862@N06/2609340717/)

And it really doesn't need to be a triple - the drive side is fine, so I really just need the non drive side.