So, time to revive! Sorry for the no reply Poldi, life and lack of funding got in the way again. I’ve spent the time actually designing some models (guitars) I can cut, so that’s an extra push to get this done.

I’ve got the servos hopefully arriving tomorrow - 4x 400w deltas, 2 for Y, one for X, one with a brake for Z. Plan is 2:1 belt drive, 15mm HTD5 belts.

I’m revisiting the Ball Screw issue now the motors are locked down - will likely get rolled C5 TBI ball screws from Fred at BST. The question is: 2020 and 1620 for Y and X, or 2010/1610?

The motors can hit 5000rpm, but are in their optimum range up to 3000rpm. This would yield a theoretical maximum of 15-25m/min for 10mm, or a whopping 30-50m/min for the 2020 screws, juuust within the critical speed for screws that size (lengths 1200 and 790mm, as a reminder). With the 17 bit encoders and the fact I will mostly do wood, I’m not particularly concerned about accuracy for either - I do need to do accurate fret slots, but figure this should still be more precise and repeatable than my slotting templates and a saw.

What I can’t quite estimate is whether the frame (with a slightly beefed up gantry) will be able to handle the super speeds of the 2020 option, and whether I may be better off with the still really more than fast enough 2010 option at these dimensions, sacrificing ultimate speed for better acceleration for possible 3D carving in my future. Or is there so much excess torque (spec’d at 3x baseline, so 3.8 NM @ 3000 rpm, but tailing off rapidly above that) that the speed gains are worth it, and design for the option to swap to 3:1 gearing in the unlikely event I want an in between option? For the Z, I’m guessing 1605 is plenty quick even with 2:1 belt reduction.

The main use will be guitarmaking (bodies - mostly arched tops - necks, inlay, acoustic bridges, fret slots and jigs/tools/templates). Maybe light metal milling (brass, aluminum) for jigs and for prototype guitar hardware. I will likely also do some sheet good cutting for smallerfurniture projects, and want to dabble with some V carving/3D carving as well. With the ample power I’m pumping into the machine, what would you guys go for in terms of XYZ pitch?