Poor Man's 4th Axis cnc

cults3d

In order to add a final touch to my model car tires, I decided to utilize a 4th axis for rotary engraving. Although the idea was somewhat vague and required significant investment, along with demanding software specifications, it didn't justify purchasing a professional 4th axis setup. Fortunately, I had a stepper motor lying around from when I replaced the y-axis, and a small chuck that I repurposed. As a result, I designed the pm4a. This build was constructed on a desktop CNC machine by Stepcraft using 6.5 mm birch plywood for the body and 5 mm Pertinax for the gears with a 1.2 mm spiral-toothed flute. Additionally, I utilized: * Two ball bearings of type 6000ZZ (10 x 26 x 8 mm) * One ball bearing of type 608ZZ (8 x 22 x 7 mm) * A small chuck (10 mm 3/8'' x 24 UNF) with an SDS-Plus adapter * A NEMA17 stepper motor * A sharpened M8 machine screw and a self-locking nut for the tailstock * Several M3 machine screws The gears feature cycloidal teeth, which allowed me to create smaller teeth without corners. This design choice was necessary due to the diameter limitation of my milling bit. To operate the pm4a, I connected the motor to the X-axis stepper driver. By doing so, the machine remains stationary while the workpiece moves in a circular motion. The distance traveled per revolution is calculated by dividing the workpiece's diameter by the gear reduction ratio (6:1). For instance, my tires have a 40 mm diameter, resulting in a circumference of 125.66 mm / 6 = 20.94 mm. I entered this value into the controller settings. When using the pm4a, it is advisable to employ some form of dust cover to prevent debris from entering the gearing. Visit https://www.zenziwerken.de/en/ for more creative designs.