Daycounter, Inc. Engineering Services Custom Firmware, Electronics Design, and PCB Layout Home Company Services Products Partners Clients Site Map Contact Us
 Capabilities Electronics Design Firmware Development Software Development Embedded Design PCB Layout Digital Signal Processing (DSP) Reverse Engineering Prototyping Device Driver Development VHDL Motor Controllers Microcontrollers Data Acquisition Systems Palm OS Software Windows CE Software Pocket PC Software Design for Manufacturing Through Hole to Surface Mount (SMT) Conversion Microchip PIC Consultant MSP430 Development DSP56 Development RoHs Redesign Design for USB

Lead Screw Torque and Force Calculator

See our other Electronics Calculators.

When designing machinery that uses lead screws, it's a common task to try and figure out the size of motor needed to drive a given force with a lead screw.  This calculator will calculate torque given the lead screw parameters and the required force.

There are two torques the torque to raise the load and the torque to lower the load.

Once the torque is calculated an appropriate stepper can be selected.

 Common Stepper Motor Typical Torque Ranges and Dimensions Motor Torque in N*cm Dimensions Shaft Diamter NEMA 8 4 20mm sq 4mm,5mm NEMA 11 11-13 27mmx sq 5mm NEMA 14 9-15 35mmx sq 5mm NEMA 17 44-54 42mmx sq 5mm NEMA 23 180-300 57mmx sq 0.25 in NEMA 34 200-1100 86mmx sq 14mm

Disclaimer - We don't guarantee the accuracy of this calculator.

 Input:: Force lbozg N Diameter inmm Thread density Threads per in cm Coefficient of Friction (See table below) Result Units N*m N*cm lb*in oz*in Result: Torque (Raise) Torque (Lower) (Selected Units)

Screw Material Nut material
Steel Bronze Brass Cast iron
Steel, dry 0.15–0.25 0.15–0.23 0.15–0.19 0.15–0.25
Steel, machine oil 0.11–0.17 0.10–0.16 0.10–0.15 0.11–0.17
Bronze 0.08–0.12 0.04–0.06 - 0.06–0.09

Equations:

These equations come from the Wiki article on force.

Torque(raise) = F*Dm/2*(L+u*PI*DM)/(PI*Dm-u*L)

We offer a broad range of electrical engineering calculators and electronics articles and tutorials

Daycounter specializes in contract electronics design.  Do you need some help on your project?  Contact us to get a quote.