140 Flat is common spindle. Kitagawa 6" chuck is 140 Flat. Royal has 140 flat in their catalog...I have 2 takisawa tt-2100g twin spindle lathes that have 140 F spindle noses. When I mention this information to royal or hardinge that look at me like a confused hound dog. I've had no luck adapting collet systems to these machines. Bastard spindle type.