`T_"lower" = ( F * d_m ) / 2*(( "l" + pi * mu * d_m ) / (pi* d_m + mu * "l" ))`

Enter a value for all fields

The Lowering Torque for a Leadscrew calculator computes the torque required to lower a load with a square thread power screw assembly.

INSTRUCTIONS: Choose units and enter the following:  Leadscrew Square Thread 

• (d_m) This is the mean thread diameter
• (d_c) This is the mean collar diameter
• (l) This is the lead
• (F) This is the load
• (μ) This is the coefficient of friction for thread
• (μ_c) This is the coefficient of friction for collar

Lowering Torque (TL): The calculator returns the torque in Newton meters (N m).  However, this can be converted to compatible units via the pull-down menu.

Related Calculators

• Compute the leadscrew torque to lift
• Compute the leadscrew torque to lower

The Math / Science

The Leadscrew Lifting Torque equation is:

   `T_R= F*d_m/2((l+pi*μ*d_m)/ (pi*d_m + μ*l)) `

where:

• TR is the torque required to lower a load using a Square Thread Power Screw assembly.  Friction Coefficients 
• d_m is the mean thread diameter
• d_c is the mean collar diameter
• l is the lead
• F is the load
• μ is the coefficient of friction for thread
• μ_c is the coefficient of friction for collar