Just about everything else looks to have been made by Bill. As an amateur machinist myself, I really can appreciate the time that went into this scope. The mirror cell is a casting that removes from the tube with 3 knurled bolts. The rotating tube rings are machined castings as well as the mount of course. The finder and rings are completely home brew with illuminated reticule. The focuser is helical. At first I figured Bill made that too. However it bears many similarities to a helical focuser I had on a 6" f/4 Cave. Any thoughts?