Well I took the head assembly down to parade rest including removing the bearings. This is gonna suck getting back together
Guyver is right on with the machining of the case for the quill to ride in. the set screw slot was pretty clean but I cleaned it up anyways. The set screw however is a POOR design and machining. I did quite abit of filing to give it more and better adjustment. Really poor design. I might look at other drills and see if they a have good one that would work. As it is you need to take the hub (lowering arm) out & more to remove the set screw and I dont think that should be the case, a simple redisgn of the screw would eliminate an awfull lot.
The bearings were all fine
I will be replacing all of them however.