A long time ago I seem to remember promising to post how I repair spindles on trailers. I finally got one in a while back and actually had time to take some pics while doing it (usually it's in the middle of the night and rush job).
I've been developing this method of repair because of all the torsion axles out there. On the old type axles I can take them out, build them up, and machine them in a lathe. However that's rather time consuming and not possible with torsion axles.
In the first pic you can see the problem. Both the threads and the outer bearing surface are ruined. In the second pic I've ground all the old bearing material that had welded to the spindle as well as chased what remained of the threads with the tool in the background.
In the third, fourth, and fifth pics you can see that I've used my 252 to build up the bearing surface and installed my guide onto the threaded part of the spindle. The cutter I'm using is one that I got at the auction of my former employer. I've never seen any others like it but I wish I could find more in different sizes. It's perfect for this application. Using the guide I simply run the cutter over the built up bearing surface. A little filing and sanding and I'm done. Please pay no mind to the stack of lock washers. I made that spindle from a found piece while fixing a trailer in the middle of the night. I didn't have time for being nice. Actually it was made from the piece I threaded to turn the nut I used to make the guide.
That fixes the bearing surface. Total time was hard to tell since I kept getting interrupted. I'd estimate about 30 minutes total to this point.
Coming up fixing the threads.