This is a CNC machine that I designed and built from scratch from
stock aluminum and steel. It is accurate to +/- .001" and uses solid
brass bearings on 3/4" x 18" steel rods. While my original goal was
to build a machine that could mill highly detailed circuit boards
for electronics prototyping, it wound up being beefy enough to mill
aluminum parts as well. I had no prior experience with metalworking
and wound up using a combination of woodworking and machinist's
techniques along with lots of custom jigs and clamps to keep from
All three axis of a 60 pound newly-minted CNC machine assembled in a frame
for the first time, proudly posing next to a couple of the tools used to
The Y axis (forward/back) height change was within .001".
The X axis (right/left) was off by .010" from one side of the work plate
to the other, but adjusted out with some tweaking on the vertical mounting
bolts and their slightly oversized holes for that purpose. To make it easier
to adjust X levelling, I turn gravity off by flipping the machine on its back.
I really like how all the mechanics came out. I tossed a
MagnaDoodle onto the plate and drew some circles.
It sounded like an air raid siren. I was absolutely giddy.
A friend of mine once jokingly asked if I'd planted the wheat to
feed the mules to bring the bauxite out of the mines to smelt into
aluminum to machine into bars for the CNC machine. At one point, I
had a rudimentary G-Code interpreter blindly outputting some bizarre
commands out COM1 to a microcontroller board driving stepper motor coil
chopper circuits at 20khz. I got the prototype interpreter and controller
working but I abandoned it after realizing that getting it as
feature-complete as I wanted and solving issues with responses and timing
was going to be more work than the raster-to-G-Code converter and the CNC
machine itself combined. Here are the schematics for the abandoned motor
controller and driver portion of this project for people to laugh at or
I bought stuff from:
- Online Metals - Aluminum bar, angle, steel guide rod
- McMaster-Carr - Nuts, bolts, washers, solid slide bearings, chuck removal wedges, mechanical odds and ends
- HobbyCNC - Motor controller and motors
- DAK Engineering - TurboCNC turns my G-Code into parallel port motor control signals
- VXB - Leadscrew Bearings
- Ebay - I bought leadscrews from two different sources that appear to have since vanished.
- The new spindle (thanks Mom!) is from Wolfgang Engineering and it's perfect. .001" details on the above PCBs are visible and repeatable. The channels are about .010" wide, but if I had a .006" or .005" mill, it looks like it would drive it no problem. I'm using an old PC power supply with the overcurrent sense pin desoldered to run it. The spindle maker's site is parked now, alas. I hope he's hearty, hale, and happy.
- To convert a screw number to a diameter, multiply by .013" and add .060"