Jim
George did say that the machine has 10 pitch screws. It looks like you've done your numbers for 5 pitch.
So, as you've already shown, the motor you chose would really do those speeds with either 10 or 5 mm pitch screws.
Of course, if you went with 10mm pitch, you could use lower rpm and higher torque motors.
George, Jim has a valid point that the primary load for this cutting action falls on the spindle. What rpm is that spindle turning? What is the chip load on that cutter and how many flutes does it have?
I'm pretty sure that my machine, with nema 23 steppers could easily make those cuts. I would have to change the spindles though as my 350 watt NSK would certainly not be up to the task.
You know George, we're all on the same side. I don't think anyone here wants to fight with you. What we do want is to have a simple logical discussion. If you could open up and talk to us about what you do know, and allow us to do the same, it's quite possible that we could all learn from each other. I'm fairly confident that we as a group have at least something that you may not already know, and I'm also pretty sure that you have things that we don't know. Unfortunately, none of that can happen if you continue to view our questions as attacks. I know that I have not attacked you, yet you react as though I have.
Ok, I'm off to the APA national championships to try to sell some cues. 3 days left!
Royce