The Rolex Explorer is an iconic watch. It's most famously (and incorrectly) known for being the watch to summit Everest, but we won't get into that here. This particular watch came in with a very worn barrel bushing. This is a fairly common problem with vintage watches that don't have a particularly good service record. Here we can see the worn bushing. A previous repairer has tried to address the problem by punch the side of the hole that has wear.
This isn't a particularly attractive solution and not the correct way to go about the repair. It did have its place back in the day for very cheap movements, but in today's world of high horology, it's not a repair that has any place. We can see the problem this worn bushing creates. The ratchet wheel has been rubbing on the plate and has worn away the plating. This is going to send metal shavings through the movement and also cause the center wheel to foul the barrel as well as hinder the automatic winding.
We first need to mount the movement in the lathe and find the center. We use a centering microsope in the tailstock of the lathe to make sure that we have the exact center before we bore out the old hole. To make the bushing we use stock brass rod and turn it down by hand. Once w have the bushing turned up to its final diameter we can ream the hole to its final size, work harden, and cut a chamfer. With the bushing now complete and installed the endshake and sideshake are correct and the watch will now run correctly.