I have an idea for a mini engaver. See the attached JPG. It will use two Vexta motors (PK264-01B, 1.8 deg., 1A/Phase) and one EAD motor with hollow threaded shaft for a 1/4-40 tpi lead screw. Has anyone seen or used one like this before? The travel will be about 2"x, 2"y, and 1"z. Programming will be interesting, because the x and y will not be linear but rotary (an A and B axis expressed in degrees.) I could manage this by generating the NC code in Esprit, but I want to find a way, if possible, to control it with x and y linear co-ordinates (but that is a different forum!)
I expect that rigidity wouldn't be a problem. The engraving bit goes to a point and would cut at max. 0.015". The natural braking torque of the steppers would be strong enough for that kind of cut.
I'll include a photo of another mini-mill I started building. I designed it with steppers, but haven't finished attaching them. Not sure I ever will. Travel of 4.5"x and 1.75"y.
The spindle with be parts from a cordless Dremel (12v DC motor with attached collet.)
Built my first Desktop mill two years ago. Xylotex driver, all EAD linear motors (same 1/40-40 lead). X and y travel of 6" and 8". Gantry style. Used a 24v DC motor and an old Flex-shaft handpiece for a spindle. About a max. feed of 5"/min. Not bad, but a bit slow for engraving. Used TurboCNC to control.
I would love to hear what anyone has to say about the mini-engraver. Or field questions.