2x small desktop CNC mills donated to MHV - ready to use!


#1

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.


(Stephen Davies) #2

@spanner888, as requested. An edited video sequence.

mhv_pcbmill1.mp4.zip (8.0 MB)


(Stephen Davies) #3

@spanner888, was thinking about the chuck problem. You have access to a metal lathe. What if this: https://www.ebay.com.au/itm/C8-ER8A-100L-Carbon-Steel-Collet-Chuck-Holder-Straight-Shank/301851432587?epid=1154641008&hash=item4647bf568b:g:1LMAAOSwiBJaSrDM were drilled and cut down to form a small ER8 chuck that mounted directly to the shaft of the existing motor?


(Stephen Davies) #4

Another productive evening at the space. Made two attempts at milling a PCB using the donated Eleksmill. Used Chilipeppr as the control software. The circuit is for a white noise generator I’ve been wanting to play with. The board was laid out using Eagle. First attempt is at the top.

The second attempt is usable but not perfect.

To do items for the near future are:

  1. Re-tension X axis drive belt
  2. Improve material holding, i.e. make some holdowns

(Stephen Davies) #5

Future improvement bookmark: http://forum.eleksmaker.com/topic/1013/z-probe-on-eleksmill/16


#6

I was about to say yes, but then noticed “carbon steel” which will make it hard to drill and especially hard to tap the grub screws.

I already have an ER11A with 5mm shaft hole, so I will make adapter for that to fit 1/8" shaft.
Also just tried hacksaw blade & light cut on this on hand one and maybe not super hard, so maybe your idea is OK. I am really not sure.

However we may also then have a height issue - ie reduced Z axis movement. This issue probably less with your approach - worse with mine.

Will keep thinking/looking as well as make the above adapter.