JD Rear Brake Drum Refinishing

[MassHarley]

I am looking for some ideas as to how I should go about refinishing my JD rear brake drum. Right now the wall thickness is very minimal. It also looks like it has started to crush over time. Here was my plan.

Make some type of shaft that will locate the drum on its center axis. With the shaft in the lathe I can see how true the braking surface is to the center line. Then I was going to take a piece of 6" steel pipe and weld build the outside so it just fit into the ID of the breaking surface. The Pipe would ride on a live center in the lathe. My hopes with the pipe is to reduce as much warping with the welding process as possible since the metal is very thin now. Once all this is assembled I plan to weld build the outside of the braking surface with a Mig machine and mild steel wire then grind to a smooth finish.

Would there be a benefit to hard facing the braking surface? Does any one know what the final thickness of the break drum should be?

Think it will work?

Mike

[Robert Luland]

Mike, if you going to go this route, don't mig! Tig! The metal your going to be attaching to is to thin in comparison to the collar. You want good penetration. I would mount the drum on the hub and jig the hub on centers in the lathe. It's down and dirty but will work as a mount. Just figure out a way to mount a turning dog to the other side of the hub. I'm going to be remaking these. We already have them but are working with my EMD guy to make a jig so we can cut the centers out of ten at a time to keep costs down. They will be cut from 4140 solid alloy. The originals were cast from common carbon steel but for what they have been put though for the last hundred years. I think the held up fantastically. The 4140 will be much stronger. We should have them to market in the next couple of months. Bob L The Good Old Motorcycle Parts Company