Cold bending 1 piece cranks?

[maniac57]

Impressive fab skillz there dude! Using whats available is good old-fashioned 'merican ingenuity!

 

[Dan]

Brilliant Wayne! Gonna make one. Thanks, big time.

Side note. Years back was reading this excerpt from a WWII Vet. He was asked "How did you do it?" He replied; "Didn't know we couldn't. So just went ahead and did it"

Is one of my favorite mantras in life.

 

[atombikes]

Nice result.

You mention using "low heat" in a prior attempt. What was the heat source? Propane torch? MAPP gas torch? Oxy-Acetylene torch? Also, what kind of tip on the torch?

If using heat, shouldn't I just be able to slip a pipe over the crankarm and bend to desired angle (no jig required)?

 

[wayne z]

I used an aceteleyne torch with a #2 tip. This puts out enough heat to quickly get it to a dull red for bending. A propane or mapp will take much longer and the BB will have time to absorb more heat, but might work if you remove the crank from the bike.

 

[dracothered]

I used an aceteleyne torch with a #2 tip. This puts out enough heat to quickly get it to a dull red for bending. A propane or mapp will take much longer and the BB will have time to absorb more heat, but might work if you remove the crank from the bike.

I think if you have a Mapp gas with Oxygen it will heat as fast as the acetylene.

 

[wayne z]

Yes that's right. I was referring to mapp only or propane only. Propane with oxy works too.

 

[wayne z]

Nice result.

You mention using "low heat" in a prior attempt. What was the heat source? Propane torch? MAPP gas torch? Oxy-Acetylene torch? Also, what kind of tip on the torch?

If using heat, shouldn't I just be able to slip a pipe over the crankarm and bend to desired angle (no jig required)?

Yes, when I used heat, I used just a pipe to bend with.