How to disassemble cottered cranks?

[pholTmonx]

Hey so on Higgins chick, the tin is coming along nice, need to prep the frame, want batch shoot as mutch as I can. Popped of the head cups and went to deal w the cranks.. 3 piece cottered. The broke free easy, but now what, I tried knocking them back with a brass hammer didn't seem to budge, what am I missing, or just let it soak first..
Thanks.

 

[LukeTheJoker]

http://www.sheldonbrown.com/cotters.html

Luke.

 

[pholTmonx]

Excellent... Easy fix w a socket and c clamp and some scrap brass.. thanks dude!!

 

[LukeTheJoker]

Socket and clamp is my go to.

You can buy cotter pin presses, but you would need to be doing it a fair bit to justify the cost...

Luke.

 

[pholTmonx]

Well attempted w a pocket machinist vise can't find a c clamp, anyway more even load... Nothing... I'll try let it soak up in penetrating oil for a bit.. thanks for the link now I understand how it works, that seems to be quite a resourceful sight, just hard navigate... Awful really if not kniw specifically what need

 

[us56456712]

I have had to drill them out when nothing else worked, including heating with a torch. There are different sizes of cotters so if you drill it you will have to find the right replacement. Use a drill smaller than the cotter and carefully go down the center of the cotter so as not to mangle up the spindle. They can be easily tapped out once they are drilled. I made a cotter remover which works great on your average cotter; they pop right out. I also user it to instal cotters. I used a short piece of threaded pipe, some furniture clamp ends with a relief hole drilled in one of the clamp ends. I sometimes have to put a large crescent wrench on the screw to get more leverage. I keep it with my bike tools and I find it faster than setting up the socket method. When I was a kid and didn't know any better I used to take a piece of maple firewood and drill a relief hole in that. Then I would put the cotter over the hole, loosen up the nut so I wouldn't goober up the threaded end of the cotter and whack it with a hammer. I put it back together using the same method in reverse. Whacking or my homemade remover won't however budge a stuck cotter.

 

[deorman]

1. Adjust nut so that tip of pin and nut are flush.
2. Repeated soaking and whacking with plastic mallet.
3. Growl insulting expletives at the bike.
4. Utilizing clamp or vice to press pin free.
5. Even if the threads survive and the crank looks straight when reassembled, search for bike shop or RRB member who has new replacements, they can no longer be trusted. Or...

My alternative method:

 

[OneHorsePower]

My alternative method:

the only method , the inventor should be punished, never had one of those that did not come loose

 

[Wildcat]

Everyone needs a garbage can that can take the blame for things going wrong, and still survive.
If you have new cotters, use a heavy steel hammer and hit it hard enough to wreck the threads on the cotter, then use a punch to knock out what's left.

 

[LukeTheJoker]

Square taper 3 piece crank sets will usually screw straight in if you do want to change...


Luke.