Just from reading what people type on here I can figure out that a 50 taper spindle is more suited to do heavy cutting. I just wanna know why. What are the physical differences between a 50 and 40 taper spindle? Is a 50 taper spindle just more robust and rigid then a 40 taper spindle? Also are there any other advantages besides heavy cutting that a 50 has over a 40 taper spindle. Sorry if my question does not make complete 100% sense. The machine shop I use to work at taught me everything about programming and set-up so I never needed to know about the specifications of machines.