Ok, been working slowly on my second machine. I posted some of the carriage pics in another thread I had started but going to gather everything under this thread now. My goal was a larger working area and a more rigid machine along with some design and setup changes. And, quite a few of the parts were machined using my original Momus CNC.
First, I needed a larger working area, starting with the gantry, I extended it 8 inches to get approx. 24 inches of tool travel. will lengthen the base by 12 inches to get approx 28 inches of tool travel...so 24x28.
Instead of aluminum I used brass for the gantry tube...more rigid for the added length although maybe overkill and hoping the added weight will cut some vibration out.
Then, instead of using multiple pieces for each bearing rail, I cut 2 exact pieces from a sold chunk of aluminum that the gantry slides into on each end as well as adding yaw bearings to the left side. Again, going for a rigid design and trying to eliminate as much play from vibration and any flexing at the joints.
Finally, I removed the belt system. Belt are good for the first build but over time I learned to dislike them No offense to belt lovers. In place of belts I went with a lead screw/anti-backlash nut setup hooked to a 495 oz. in. stepper. My original setup had 270 oz. in. which worked great, 495 is overkill but what the hell. The advantage to the lead screw setup is fewer parts, the disadvantage is everything needs to be squared and aligned or its gonna destroy the anti-backlash nut and bind up the carriage.