CNC mill parts
Sunday, 2 October 2011
Tonight I finally finished the metal parts for the CNC conversion. These were made from a subset of the “phase 1″ plans I purchased, and are all the custom parts I need to attach my stepper motors to the G0704 mill.
Most of these were pretty straightforward. The standoff-looking parts are steel rod, parted off to length and then drilled and tapped. The fatter bushing-looking things are aluminum, also round rod that was drilled out then trimmed to length. The big flat aluminum parts were a little more challenging, requiring some milling, but the holes were all center-punched and drilled on the drill press (I still don’t trust positioning on the mill due to the backlash in the screws).
This cylindrical steel part took several hours. Starting from a 1.5″ steel rod, I first turned the skinny stem part, then flipped it around to bore out the inside. The tricky part was getting the piece clamped into the lathe so it was perfectly concentric to the shaft I already turned. Apparently my three-jaw chuck is not perfectly centered, so I used the four-jaw chuck and aligned the part manually using a dial indicator attached to the cross slide. According to the indicator I got within half a thou for concentricity… good enough!
Once it was centered I bored out the inside and put the little shoulder on the end. Next it was drilled and tapped (for set screws), then off to the mill to make the flats on the shaft.
The most challenging part was probably this aluminum bearing block, shown here in the four jaw chuck. Again, concentricity here is key, so a lot of time was spent getting this guy aligned when I flipped it around.
Technically I’m ready to mount the motors to the mill, but I’m hesitant to start the process. I’ve gotten used to having a milling machine available, and once I take the handwheels off it’ll be out of commission until the CNC conversion is complete and working! Here we go…