Multi Start Screw Lead and Travel Calculator
Relate axial thread pitch, starts and mean diameter to lead, helix angle, travel speed and entered-efficiency torque.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Multiply axial pitch by starts to get axial advance per revolution. Use the helix developed on the mean-diameter cylinder for its angle. Relate axial work per revolution to torque.
Lead=starts×pitch; helix angle=atan(lead/(πd)); input torque=force×lead/(2πη)
Worked example
Pitch 2 mm and two starts give lead 4 mm/rev. Travel 100 mm takes 25 revolutions; at 120 rev/min the ideal travel time is 12.5 s.
Assumptions and input details
Mean diameter and forward-drive efficiency are supplied assumptions, not derived thread specifications. Excludes friction laws, self-locking, backlash, acceleration, critical speed, bearing loss and strength checks. Torque is an energy-balance result for the entered efficiency; no actual mechanism is controlled.
Unit definitions
Unit selection is independent of language. Each selector contains only units for its physical quantity. Calculations use defined base units internally.
Choose from 23 length definitions, including explicitly labelled regional measures. Area conversions square the length factor; geometric volumes cube it.
Regional measures are not interchangeable merely because their names look similar. This is a documented selection, not a claim to include every historical unit.
NIST measurement tables · Japanese traditional units · Mainland China and Hong Kong unit distinctions
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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