Time to revisit this thread... The upgrades I made to the X & Y axes are working well. I can now get rapid moves of 1200 and 1300 mm/min respectively, which I think is quite a respectable pace. However, since I started trying some v-carving, I have been having issues with the Z-axis sticking on upward moves, so that the next downstroke would plunge the tool deep into the workpiece and ruin it. The tool mount was also showing some flexing during cutting, which was introducing inaccuracies in the final product.
Time now to re-design and rebuild the Z-axis, while sorting out a few small irritations with my first design.
- make the stroke longer so that the new spindle with my longest mill can clear the working area.
- lift the whole axis so the base is level with the bottom of the gantry to maximise working height.
- eliminate the leadscrew and nut protruding from the bottom of the axis, again maximising working height.
The new axis will now be built around a TR10x2 leadscrew (the same as the Y-axis), with a longer tool mount, and all structural parts made from 18mm MDF instead of 12mm to improve the stiffness of the tool mount.
I had to slow the Z-axis right down to a crawl to stop the sticking on the upstroke, so cutting the parts for the new axis took some time, but this is now all done, and ready for assembly.