Bootstrapping my way to CNC control

Since the Y axis had two handles, I was able to remove the collar from the right hand side and then machine the collar on the mill. Shortening collar let me mount both a pulley and the original handle on the right hand side of the lead screw.

I made the wood parts out quarter inch poplar, as I planned on making the final versions out of quarter inch 6061 aluminum. In retrospect I would use thicker aluminum plate.

The motor mount was made from two plates, one bolted to the face of the motor and that plate in turn bolted to the support plate. This design let me adjust the distance of the face of the motor from the supporting plate. This in turn lets me control the position of the bottom pulley relative to the top pulley on the axis. This adjustment ensures that the pulley hang in line with each other.

In these pictures you can see the temporarily mounted wooden supports. Since they would only be use briefly I just clamped the forms in place. Later I drilled and tapped mounting holes for the aluminum plates.

Once the motors were mounted on the X and Y axis I dialed in the mills accuracy with software backlash calibration. I tested this by milling test patterns, mostly circles in wood. Essentially once you get the circles to stop being ellipses to within you desired accuracy you are good to go. Fairly sloppy when compared to a mill properly set up with ball screws, but good enough for my purposes.

So seriously, buy a bandsaw. I got mine from craigslist and it totally transforms your shop experience. Cutting through even a small plate like this would have been 5-10 minutes of strenuous work, but instead I just locked the plate in the bandsaw and walked away to do other things while it cut. That might now sound like much but with even a small project that can save you an hour out of your day and that is saying something. I noticed a huge boost in my own productivity.

Here you can see some of the pieces I milled to replace the wooden templates. Since I just bootstrapped the X and Y axis I put pauses in the g-code so I could adjust the Z axis by hand.

This design worked, but if I had it to do over again I would have used slightly thicker plate. When running the mill with any speed the torque on the Y motor mount slightly bends the plates. I hung the motor so far below the mill bed to maintain maximum travel by ensureing that the motor did not hit the knee. Works, but like I said it could have used thicker plate.

The X axis.