Bending a Dana 3-speed crank

[g-ratter]

Welding the crank will be a little more of a challenge than I expected but my friend says he's up to it. Apparently the process will require heating the whole crank arm to about 1200F, weld up the cuts, then let it cool in sand.

Why the heat up first?

 

[LukeTheJoker]

Why the heat up first?

The weld material when it goes in is hot and expanded, if the parent metal is cold the weld will shrink away from it as it cools and could cause cracking in the heat effected area surrounding the weld.

Luke.

 

[g-ratter]

So is this a technique for welding everything or just thicker pieces?

 

[LukeTheJoker]

So is this a technique for welding everything or just thicker pieces?

Usually anything cast/forged/of unknown quality...
Theoretically you probably could do it with everything, but it is not worth the added time and effort with quality steel that reacts predictably.

Luke.

 

[Harold_B]

Hey Harold_B, how has your dog-leg crank arm held up?


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Poor or worse. What a fiasco. I wound up breaking one of the crank arms completely and just made my own from steel plate. Since this thread was posted I had rebuilt the bike, then dis-assembled and parted it out. One of the few things I've kept is the Dana.

 

[g-ratter]

Usually anything cast/forged/of unknown quality...
Theoretically you probably could do it with everything, but it is not worth the added time and effort with quality steel that reacts predictably.

Luke.

Thanks for the info. Love learning something new.