Old bike restoration - cotter pin stuck

[accountantpete]

Best bit of advice from the Sheldon article,

Hold the hammer by the end of the handle, and give it everything you've got! It may work, or you may just bend the end of the cotter over. If you bend it, use the claw of the claw hammer to straighten it, then try again. If you repeat this cycle unsuccessfully a few times, the threaded end of the cotter will snap off.

Modern translation :You have to get medieval with its ass!

 

[cyberknight]

Technical term is percussive maintenance

 

[SkipdiverJohn]

Just banging cotter pins with hammers is the reason they end up getting bent over and mushroomed. Never ever completely remove the but from a threaded fastener you want to drive out., or you get the result in the photo. Just slacken it a turn or so at a time and hit the flat side of the nut with a flat faced tool.
Since the pin in the photo has been totally butchered now, the only way that is coming out is penetrating fluid down the taper and some serious brute force from a big hammer and a pin punch. Support the crank underneath using a block of wood with a hole drilled in it or use a car axle stand to concentrate the shock loading where it's wanted, not into the bike frame..

 

[classic33]

Just banging cotter pins with hammers is the reason they end up getting bent over and mushroomed. Never ever completely remove the but from a threaded fastener you want to drive out., or you get the result in the photo. Just slacken it a turn or so at a time and hit the flat side of the nut with a flat faced tool.
Since the pin in the photo has been totally butchered now, the only way that is coming out is penetrating fluid down the taper and some serious brute force from a big hammer and a pin punch. Support the crank underneath using a block of wood with a hole drilled in it or use a car axle stand to concentrate the shock loading where it's wanted, not into the bike frame..

The pin in the first post shows no damage!

 

[raleighnut]

The pin in the first post shows no damage!

Yep he's only took the nut off.

 

[SkipdiverJohn]

The pin in the first post shows no damage!

My mistake, at a quick glance it looked bent over in the third pic. In that case put the nut back on 1 turn short of touching the crank arm. Belt the f*** out of it with a 2 lb hammer until the pin moves and the nut then touches the crank arm. Undo the nut another turn and repeat until it can be gently tapped out with the nut removed without damaging the thread.
So long as you don't beat a cotter pin with the nut removed when tight they can almost always be re-used and old ones are usually better quality and made of harder steel than modern ones. Never bin an original one if it can be refitted.

 

[HMS_Dave]

"If it can't be fixed with heat and a lump hammer, it goes in the bin..."

 

[tyred]

The most important things are to support it and also to hammer it properly with determined whacks holding the hammer at the end of the handle. Many people hit things with little gentle taps but that just rivets it in place.