Many, many years ago about 30 or so I worked for Aero Kool corp hialeah fl. We had the industrial side (Turbo Tech) and the Aero Kool aircraft side. I ran the industrial side. We rebuilt turbos for everything that flys or runs on the ground. My expertise was to not only run the shop but to design better ways to rebuild the units and teach people how to do it. We actually Helli-arc welded the worn edges of the aluminum side and using air die grinders to grind them to the proper thickness. Then lathe turned the contour to match the housing. Did the same on the exhaust side using different materials. There are two bearings, actually bushings made out of brass alloy. Each has six holes about .090" for oil. When the unit spins up, some to 30,000 rpm the inner, shaft and outer, housing bearing surface rides on about .0015" film of oil.
Once the bearing get to much play the driven side and the output side wears into the housing destroying the entire unit. One of the first signs is raw oil out the exhaust. One of the worst things anyone can do is to shut an engine down to fast. This drops the oil pressure while still spinning fast and scores the bearings. Even at start up, racing an engine before the oil get to the bearings will start to destroy it. Knowing what I know, I would spend the money and buy new.