[wp6529]

A project to repair badly worn areas on two cast iron hubs has landed on my bench. These hubs are pivots (partial rotation and slow) that normally ride in a nylon bushing and when those bushings wore out they didn't get replaced resulting in a large amount of wear up to about 3/8". From what I've found searching around it appears the best bet for repairing this is to TIG braze build it back with ERCuAl-A2 Aluminum Bronze, and 300-400F pre-heat on the hubs. Once built back I'll turn it back to size on the lathe, and the hubs can also be reinstalled clocked 180 degrees so the main bearing weight is on the non-repaired side.

Thoughts, tips, etc?

Thanks,

Pete

Hub

hub.jpg (782.01 KiB) Viewed 2716 times

[cj737]

I’ve never used it for that amount of build-up. I would probably prefer to a flame spray method applying powdered iron. 3/8” is a heap of build-up to rely on an alloy (in my opinion).

[Coldman]

I recon a flame spray method would be the way to go. If you don't have access to this method there is another way.

Tig a couple layers of EziTigWire on the bottom and sides of the repair surface. This wire does not require preheat on the cast iron part and is also used to joint steel to cast iron.

Once you've got a buttering layer of expensive EziTigWire down you can fill the rest of the repair with cheap ER70 tig wire. Once you have a few layers if ER70 down you can even switch to mig to speed the process up. Solid repair.

[wp6529]

I've seen a number of high build videos using the ERCuAl-A2 Aluminum Bronze, including a Jody vid building an entire vise mounting ear from all buildup. Since this will be entirely in compression or even no load since it's just a pivot and can be re-clocked to put the load on the un-repaired side, I don't think the high buildup will be an issue.

[BillE.Dee]

I'm going to have to go try like coldman said. I've used the eztig wire and had more trouble with the cool down than the start. I have no idea what the wear factor will be with that, BUT, it is mentioned the hubs can be clocked to move the wear factor to a new area. Hopefully you can get the bearings out of the way.

[wp6529]

Much chaos and delays in getting to work on this, but some progress. I have one hub finished and the other well along now. The second hub was worn so thin I had a bit of drop through to deal with and as a result I didn't get a portion of it filled sufficiently so i want to revisit it and improve it. I think they should be quite servicable and last a long time if the bushings are maintained properly. Not stellar, but I don't do this every day either.

Hub_filled.jpg (577.22 KiB) Viewed 2576 times

Hub_filled2.jpg (598.15 KiB) Viewed 2576 times