Okay... so assuming I have a "goal" ralative to spindle HP, Feed Rate's, etc. Is it correct to assume that I could build the router (ball screws, servos/steppers, encoders, etc) with that target in mind and use the 3.5HP router... even though I might not get the maximum potential from the router until I upgrade the spindle... keeping in mind that I would have to adjust the servos accordingly? Guess what I am thinking, is all I want to do is upgrade the spindle... not rebuild the entire mill...
... Another off-topic question... I see a lot of pneumatic actuators and guide systems... but no one seems to be using them for CNC axis control... What are the issues, drawbacks or restrictions with these...