I built a small extractor also, but I haven't had a chance to try it yet. It too is limited by the barrel size (it is based on a tub 18 inches in diameter), so it will only spin four frames. Mediums radially, and deeps tangentially.
I found that 1-1/8 inch holes fit "standard" (although I shy away from that term) Dadant frame tabs nicely, eliminating the need for machining. It has a rotating shaft design that turns in sealed bearings top and bottom with triangular flats ground onto the end to (loosely) fit a 3/8 in drill and rather than slowing or stopping, just lift the drill to disengage it and let it spin down. Works good with empty frames.
About $70 in parts and I had a great fun making it.