Classic & Vintage - Advise on straightening a crank arm

Hi guys, I bought an old dutch 3 speed with a bent right crank arm, it is actually a bit twisted. I really don't want to replace the crank as its kind of cool with HARTOG lettered in the chainring. So my plan is to clamp the crank end in the BFV, screw a long bolt into the pedal thread, and put a twist on it with a cheater pipe if necessary. My question is do you think I should try to cold bend it or heat it up a bit with a torch?

Cold! Definitely not hot.

I would put the pedal end in the BFV and apply force to the other end, any number of ways. Plan A, if you had to move it a lot, might be a heavy metal bar with a 5/8" hole in it and a 5/8" bolt through the spindle bore.

Then all force would be applied to outer surfaces, and none to the threads or spindle more.

Does BFV stand for Big ****ing Vise?

Does BFV stand for Big ****ing Vise?

Yeah, just like hit it with the BFH

Cold! Definitely not hot.

I would put the pedal end in the BFV and apply force to the other end, any number of ways. Plan A, if you had to move it a lot, might be a heavy metal bar with a 5/8" hole in it and a 5/8" bolt through the spindle bore.

Then all force would be applied to outer surfaces, and none to the threads or spindle more.

Thanks for the input, it doesnt have to move much, maybe 1/8" and 5 degrees of rotation or something. I think its fixable, I thought heat might help it bend, but then wasn't sure if that would weaken the steel.

Hi guys, I bought an old dutch 3 speed with a bent right crank arm, it is actually a bit twisted. I really don't want to replace the crank as its kind of cool with HARTOG lettered in the chainring. So my plan is to clamp the crank end in the BFV, screw a long bolt into the pedal thread, and put a twist on it with a cheater pipe if necessary. My question is do you think I should try to cold bend it or heat it up a bit with a torch?


Interesting! Does it say 'Teha' anywhere on the bike? That should be the brand, the name Hartog is the name of the owner of the factory.

http://www.oudefiets.nl/4merken-t.html

Fourth line from the top of this page.

Shouldn't be a problem with a steel crank arm. My LBS had a tool/jig/fixture they used to successfully straighten the non drive side aluminum crank arm on my Centurion Pro Tour when I fell on ice & bent it. Steel should take the correction better than aluminum.

No it doesn't say Teha anywhere, it is branded Hartog on the Head Badge, seat tube, down tube, and the chainring. I haven't been able to find much information on the internet. I think the page you referenced only covered bikes made until 1938 and this bike is a 1964. I couldn't get a decent picture of the headbadge, it is in my basement and the lighting is poor. Here is a pic of the chainwheel though.

Cool Ollo, that makes me feel better, I'll give it a shot when I get a chance.