Of course, those are rapids, on the cutting speeds that depends on the material etc. When testing I usually cut a piece of HDO, and that will cut at max with no problem.
On the Mill Turn they have re-cast the main bed with a couple of ears at the tailstock end to support the linear rail shafts. They also re- cast the lathe column as a solid piece and with some extra support for the 4 linear rails on that end. That eliminated that bolt on steel plate they used previously. Dimension wise, everything looks pretty much the same, so a guy with an older patriot machine could probably upgrade to the newer mill head pretty easily, you would just have to build some sort of bolt-on support at the tailstock for those columns.
I think JT was a bit too conservative on his drive ratios on the mill head. He used an 18 tooth motor pulley and 72 tooth drive pulleys for a 4-1 reduction. I put a 36 tooth drive pulley on the motor to go to 2-1 reduction and the motor handled it just fine. On the downstroke I could actually get 90 IPM, but on the upstroke, lifting all that weight, it maxed out at 40 IPM. I am going to try a couple of gas struts to balance the load, and with luck I may end up somewhere in the middle of these 2 figures around 60-65 IPM. Stepper motors have a sweet spot at which the torque maxes out, and once the RPM goes beyond that point the torque starts to drop off rapidly, so its possible that the motor could handle a 1-1 ratio drive, but mounting a 72 tooth pulley on the motor just doesn't look like a possibility, so that would entail changing the 2 driven pulleys to 36 tooth.