Atlas Horizontal Mill? - Practical Machinist
About the Atlas Horizontal Mill . . . the spindle is threaded 1x10 with an MT2 taper -- the same as later model Atlas/Craftsman 6" lathes. So chucks, faceplates, boring heads and milling cutter holders are readily available on eBay and from various vendors of new items. Clausing still sells many parts for the old Atlas/Craftsman machines.