Forrest
I think you should seriously consider the X3. I got mine from harbor freight as a special order using a 20% off coupon and had it loaded in the pickup for about $860. I had spent nearly that much excluding CNC on my X2 to get extended Z range and stop the gear breakage. While I am still planning to add ballscrews to my X3 (I have the screw and nuts waiting for machining) I made a no mod to Mill conversion with stock screws so I have the X3 running at 30 ipm on X&Y and 20 ipm on Z. All I did was replace the Y and Z cranks with Stepper motors (Clamp on Mtr Mount and split coupler) The X was even easier, The X3 comes ready for an X power Drive. I mounted a Stepper mount to the pre tapped holes and made a coupler to match the end of the screw. X3 screws have a split nut arrangement that allows adjustment for backlash. They recommend .003 inches of backlash that most Machining software can compensate for. I am using the drivers and the same motors that I had on the X2 for x and y. Z took a Nema 34 motor to get the above results. Once I go to Ball Nuts I expect to double or triple the performance. That is the results I had on the X2. The advantage of this initial step is that I have a CNC machine with modest performance to use while I prepare the ball screw conversion. I didn't think it was much harder or expensive than preparing a bunch of Chinese scales to have a DRO on a manual machine. This assumes that the investment in motors and drivers is one time. On my X2 I removed the digital scales once the steppers were up and running as they had higher resolution and less backlash than my homemade DRO. Thus on the X3 I went straight to the steppers.
X3 does not have the same level of problems with losing tram and stiffness that the X2 has as well as more power, and range in all three axis. Plus more room for ball screw and nuts. It also already has a screw for the Z axis instead of rack and pinion.
Hubert  |