Tarantula Reframed & Reloaded, easier to print Dual Z-belt drive

thingiverse

This is a remix of the Z-drive portion of this design: https://www.thingiverse.com/thing:3226089 You will need some parts from the older design. UPDATE 1/14/2020: new 67 tooth gear with 4 set screws to really dial in the centering and true everything up. UPDATE 1/9/2020: new gears are a higher ratio so less chance of a slowly falling gantry when steppers are off, and better resolution. The parts are oriented in the best position to be printed. Depending on the weight of your X gantry, how tight everything is, and the holding torque of your motor while powered off, this setup may slowly coast down. If that's a problem: increase pressure of the gears against each other, or make some gears with a higher ratio. ###The firmware needs the Z axis reversed, and the Z steps need to be 541 steps/mm (the stock lead screw is 1600 steps / mm) Of course set it to 541 and calibrate from there. __How the math works out:__ **The ratio of the gears is 9/67 or about 7.444:1, which turns the GT2 pulleys with pitch diameter of 14.01 mm.** **Pulley Pitch Circumference: (pi) 14.01mm = 41.01mm** **Distance moved by belt per motor revolution: 44.01mm / 7.444 = 5.912mm** **(1.8 degree stepper: 360 / 1.8 = 200 real steps per rev)** **Z belt distance moved per real step: 5.912mm / 200 = 0.02956mm** **With 16x microstepping: 0.02956 mm / 16 = 0.001848mm** **Microsteps per mm required = 1 / 0.001848 = 541.25** **Rounded: 541**