Hello All,

This is my first post and probably should have been an intro but I came to the forum to find some answers so here goes...

I am fabricating a Clutch actuator lever for a 1929 Harley Davidson motorcycle and have a need to bend the machined shaft about 90 degrees. I made the new part out of 9/16ths 1018 CR round bar. Might not have been the right kind of steel to use for this but that is all the local Metal Supermarket had in the right size.

Here is a link to some pictures of the old clutch lever and the new machined shaft I have to bend. When all is done the less tendency for the shaft to twist the better since that is the action on the clutch lever.

Harley Single Clutch Lever

Thanks in advance for any advice.....

Mike Ritchey
Acworth, GA

Since is is mild steel just heat it where you want it bent and bend using a pipe or bar of the most suitable radius. If this stretches too much on the curve, again because it is mild steel, I'd build it up with weld and grind smooth.
Now if it is springy, you may need to step up to a med carbon steel (1045, 4140) Which can be had through an industrial supplier.

Welcome aboard Mike, glad to have you.

Mild will bend easily hot. Heat it slowly to make sure it's hot all the way through, to med orange and bend it around a mandrel/jig the right radius. Let it cool in open air or just drop it in the dirt. Aligning it to magnetic north is optional.

Frosty

Mills: perhaps you weren't using the terminology you ment to, but all steels have the same "spring" regardless of heat treatment or chemistry. Now mild steel will yeild sooner, but when you apply, say, a ten pound load to either one they will both deflect exactly the same, they have the same stiffness. Now at a certain point the mild piece will "take a set" where it won't return to the orginal point, but until that point is reached, all steels are equal.

Actually, now that I've looked at the pictures, I would reccomend you bend the part cold aroud a 1-1/4" dimeter pin to avoid removing the cold-worked hardness of your CR part. Best if you can find someone with a real bender, like Diacro or Hossfeld.

Edited June 3, 200917 yr by nakedanvil

Thanks everybody for the replies. My initial thought was to just heat where the bend was to go to a nice red and then bend it around a piece of an old bearing race that has the right curve. I started reading some of the threads in the forum about CR steel and then started thinking I might loose most of the stiffness that the cold working had imparted to the metal so that is the reason for my original post. I have another piece of the bar that I might try heating and bending but I am going to see if I can find someone with a bender as Nakedanvil suggests. Thanks again for all the replies!!!

Mike Ritchey

If you find someone to bend it, make sure they use at least 1-1/4 diameter pin. 9/16 is unlikely to make it around a 1" pin cold. Polishing the area of the bend helps reduce the chance of cracking too. Lathe turning marks are the worst, filing lengthwise is preferred to circumferential marks.

Actually, I have a HF bender on a stand that could make your bend cold. A pretty good strain on the bender and operator but with a 6 foot bar 9/16 is doable. My bender is bolted to the floor with epoxy grouted bolts. The dies go to 2 15/16 diameter.
one thing that I notice is that the bend in the original appears to start early where it leaves the housing before it gets to the major bend. Is that intended or is it just an artifact of age??