Key Force Calculator:
Enter the values of torque, T(lbf-in) and diameter of the shaft, D(in) to determine the value of key Force, KF(lbf).
Key Force Formula:
The key force in mechanical contexts often refers to the force exerted by or on a key that is used in a mechanical assembly to transmit torque from a shaft to an attached component, like a gear or pulley.
Key Force, KF(lbf) in pounds-force is calculated by doubling the torque, T(lbf-in) in pounds-force inches and dividing by the diameter of the shaft,D(in) in inches.
Key Force, KF(lbf) = 2 * T(lbf-in) / D(in)
KF(lbf) = key force in pounds-force, lbf.
T(lbf-in) = torque in pounds-force inches, lbf-in.
D(in) = diameter in inches, in.
Key Force Calculation:
1.Calculate the Key Force required for a torque of 100 lbf-in applied on a shaft with a diameter of 2 inches.
Given: T(lbf-in) = 100lbf-in, D(in) = 2in.
Key Force, KF(lbf) = 2 * T(lbf-in) / D(in)
KF(lbf) = 2 * 100 / 2
KF(lbf) = 100lbf.
2.Assume you need to find the diameter of a shaft that is subjected to a torque of 120 lbf-in, and the required key force is 240 lbf.
Given: T(lbf-in) = 120lbf-in, KF(lbf) = 240lbf.
Key Force, KF(lbf) = 2 * T(lbf-in) / D(in)
D(in) = 2 * T(lbf-in) / KF(lbf)
D(in) = 2 * 120 / 240
D(in) = 1in.