An extremely genereous person has donated the two mills below to MHV. They are capable of engraving & cutting plastics, rubber stamps, wood, PCBs and maybe with extra care soft aluminium.
Both are tested and in working condition, but do need some hopefully minor fixes/improvements.
Both mills use an Arduino running grbl gcode controller software, which means you can use your own preferred design toolchain and gcode senders such as Universal Gcode Sender, or bCNC etc.
Pictures (sorry really bad - see web links for better) & notes below provide really basic summary. If enough interest, we can create wiki pages to carry the doco forward.
Mill #1 Pocket NC FR4
A very interesting frame design that has almost no wires, as the entire frame is a PCB that contains 99% of the wiring.
Spindle and collet seem very nice.
Homing of the mill works nicely. Have not yet tried to run any gcode are do actual cutting.
Probably not super accurate as lead screws and rods seem to be standard hardware items and small diameter, but still highly useful mill.
Z axis has at least 2mm Z wobble - can see the linear rods are loose. Hopefully not too hard to fix this. But overall not a super stiff & accurate mill, so suited for very light loads only. Maybe this one could be set up as the laser engraver/cutter (see below), although a larger frame/work area would be better, and of course the big laser cutter is hopefully getting close to shipping.
Mill #2 Elecs Maker Mill
Very robust frame, bearings, slides etc.
Larger diameter linear rods - probably chrome plated, not hardened steel.
Proper lead screws, not threaded rod so more accurate.
z axis has rough pitch ie moves fast
No home switches, so need to be carefull you do not move mill outside workarea!
Have run a test job (but no tool/cutting).
Mill moves well and looks very promising, except the DC motor spindle has a probably CRAPPY grub screw collet (have not yet mounted cutting tool and tested). Probably very worthwhile upgrading this so easier to change tools and to reduce runout/wobble.
Also a LASER addon…box says 500mW. BUT there is absolutely no cover/protection. This MUST be made as well as fume extraction before laser could be used.