A homebuilt 3-axis CNC router made from a mix of surplus hardware, fabricated wood & sheet phenolic parts, and DIY control system electronics purchased online. Our first attempt, and yes it shows, but it won't be our last now that we know how easy it is to do.
This little tool is capable of 0.0005" theoretical positioning accuracy based on the controller parameters, stepper design, and lead screw pitch. In reality, mechanical tolerances and flex in the gantry knock that number down (up?) to a few thousands. Still, it's good enough for our design and prototyping business until we can save up for something bigger, faster, and more accurate.
Happy to entertain questions about its construction. The basics:
Thomson linear bearings (wouldn't use end-supported rails again, but couldn't beat the price we paid for these gently used units).
305 oz-in steppers, 200 steps/rev without any microstepping
Acme profile, 1/2" diameter, 10 thread-per-inch lead
Torsion box bed made from plywood and MDF
3-axis DIY controller kit from Hobby CNC
EMC2 control software running under Linux Ubuntu on an older dual-boot PC
CamBam toolpath generation software until we can afford something more exotic (very happy with this little $149 gem)
26" X 21" X 6" working envelope
3.25 Hp variable speed Porter-Cable 7518 spindle motor
Precision collets down to 1/8" diameter
Total investment so far: $1,600
