Tools for cottered cranks
 

It's been a long time since I've dealt with cottered cranks but now I have two bikes I picked up from CL to deal with that have cottered cranks (a Raleigh sport and a "Roger competition", http://www.bikeforums.net/classic-vi...ine-parts.html).

I've removed and installed cottered cranks before with just hand tools but I know this is not optimal so I want to either buy the right tool or make something that works.


Is this is a slam dunk situation and I just need to pony up the cash for a cotter press from bikesmith design, New Crank Cotter Press Has anyone used this tool? If so, how well does it work?

Alternatively, is there a "home made" solution that works? Sheldon Brown's website talks about using a length of pipe tubing that can be wedged between the crank and the floor. Cottered Cranks

That makes sense. Has anyone tried this and how well does it work?

Or there other ideas and/or alternatives?

The Bikesmith Designs press has worked well for me. It is very beefy and built to last as well. It looks like the new model is refined a bit, but the old one isn't lacking in functionality as far as I can tell from my usage.

In the Classic & Vintage forum, I have seen plans to build one from something else, perhaps a motorcycle chain tool, and I think I have seen other home brewed options as well. To me, these were more trouble than buying the press, but it depends on your personal priorities and skills. :) If you search that forum, I am sure you'll get a variety of processes and opinions...

For beaucoup years I got by without a cottered crank tool by simply hammering the cotter pins in and out, carefully, using a block of wood to protect the pin from the hammer. Eventually I got the Park Tool (photo) which may or may not have simplified it any. I think a hammer/wood block combo sounds good if you don't have the tool.

http://bikeforums.net/attachment.php...hmentid=381836

The tools above are fine, and might make sense if you plan to remove cotters on a regular basis. However they are not necessary and even when cotters were SOP on 95% of cranks, many mechanics, even pros do without.

The tools needed to remove cotters are knowhow, hand skill, a hammer, and something to dolly the crank.

Here's how I do it -- works every time.

1- find a length of pipe long enough to reach from the crank arm to the ground, or something to use as an anvil, ie. bench vise.
2- back cotter nut off 2mm or so.
3- brace the dolly (pipe) under the crank so that any hammer blow delivered will not be dissipated by the crank "rolling with the punch". Good bracing of the crank is key because that's what concentrates the hammers energy in the pin.
4- deliver a solid blow to the pin and it'll move. This isn't a process of tapping it out, but driving it half way to China with a single shot. Solid blos move the pin, weak blows just mushroom the end.

4.5-- if you have doubts about your hammer skills, or are afraid you might hit the chainring, hold a punch against the cotter and drive it with that.

Hammering out the cotter insures you will probably need new cotters , and likely filing the taper before you set the new ones .

the press improves the chances to reuse the existing cotter.

yea banging on the pin on the bike and having air filled tires absorb the blows is a exercise in futility . :rolleyes:

Just use a bench vise. It's easiest if the bike is stripped down, but it can be done with just the wheels off. Put a socket over the end of the cotter, and start cranking down on the threaded part. Cotter should pop out, and be in good enough condition to reuse. I've had success with this method on 4 different cranksets.

This is an excellent method if one has a decent vise. I don't think of it because I have consistent good luck with a hammer, and it's a PIA to lift bike and position the crank and socket while tightening the vise (a friend helps).

Also, I've seen the thrust plate on some vises fail, so care should be taken to be sure vise is built for this kind of load. The general rule is that if you need a cheater bar on the handle, you're nearing or passing the design load.

I expect a large C-clamp using a socket on the "anvil" end of the clamp and using the screw press on the threaded end of the cotter (with the nut still there to protect the threads) to press out the pin would also work as well.