K8200 Z-axis gearing

thingiverse

I Improved z-axis precision by adding a 1:3 gearing ratio to the printer's stepper motor. This moves the stepper from the bottom up to the top, requiring some adjustments. See instructions below. Attention: Be aware that the stock M8 screw may not be long enough for this upgrade, and you might need to replace it. Custom Section Adjustment Settings for the New Z-Axis Ratio These instructions are specific to the Marlin firmware that comes with the K8200. To change the rotation direction of the z-stepper, swap two of its four phases on the controller board. - Swap pins 1 and 2 or 3 and 4 of the z-stepper connector. - Do not swap pins 2 and 3 or 1 and 4 as this will cause issues. Depending on which z-arbor you have (M8x1.25 or TR8x1.5), adjust the following z-steps per mm settings in your Marlin g-code. Change stepping: For M8x1.25: set steps per mm to 7680 with "M92 Z7680.00" For TR8x1.5: set steps per mm to 6400 with "M92 Z6400.00" Store these settings in EEPROM with "M500." Test the new settings: - Check if the z-axis moves in the correct direction. - If it moves incorrectly, manually press the z-stop button to emergency stop it. - Check if the z-axis covers the correct distance by using a digital caliper between the z-arm and top frame crossbeam. - Verify that homing the z-axis still works correctly.