What this tool calculates
Separate screw pitch from screw lead so a Z-axis hardware change produces the correct motion setting.
Formula and method
Lead = screw pitch × thread starts. Steps/mm = full steps/rev × microsteps × motor-to-screw ratio ÷ lead. For direct coupling, Klipper rotation_distance equals the screw lead.
When to use it
Use this when replacing a Z lead screw, changing a motor, changing configured microsteps, or adding a belt reduction between the motor and screw.
Worked example
A common T8×8 screw has 2 mm pitch and four starts, giving 8 mm lead. A 1.8° motor at 16 microsteps and direct coupling produces 400 steps/mm.
Assumptions and limitations
Pitch and start count describe the nut and screw pair actually installed, with no unmodeled gearbox. Backlash, screw straightness, nut preload, coupler alignment, and bed mechanics are not captured by steps/mm.
Common mistake
Do not enter the 2 mm pitch of a four-start T8×8 screw as its travel per revolution; the lead is 8 mm.