Re: Atlas 10" Serial Numbers and Bearing Dates Robert; Here are a couple other things I noticed on this model (H36) 10" F lathe: 1. The on/off switch has an oval shape (not rectangular) 2. The set screws on the countershaft "hanger" have hex heads, not single blade screw heads 3. The half-nut lever is not fastened on by a screw; it's pinged on by a ball peen hammer There may be other small nuances I haven't discovered yet. So far, your hunch places it at about 1939 vintage; according to your last post, approximately 100,000 10" model F lathes were produced. Is this right? Lou O.