Enter the helix angle (deg) and the coefficient of friction into the calculator to determine the Lead Screw Efficiency.

## Lead Screw Efficiency Formula

The following formula is used to calculate the Lead Screw Efficiency.

**Elead = tan(ha) / (tan(ha + arctan (f)))** *100

- Where Elead is the Lead Screw Efficiency (%)
- ha is the helix angle (deg)
- f is the coefficient of friction

## How to Calculate Lead Screw Efficiency?

The following two example problems outline how to calculate the Lead Screw Efficiency.

**Example Problem #1:**

- First, determine the helix angle (deg). In this example, the helix angle (deg) is given as 50.
- Next, determine the coefficient of friction. For this problem, the coefficient of friction is given as .65.
- Finally, calculate the Lead Screw Efficiency using the equation above:

Elead = tan(ha) / (tan(ha + arctan (f)))

Inserting the values from above and solving the equation:

Elead = tan(50deg) / (tan(50/57.2958 + arctan (.65))) = 14.5 (%)

**Example Problem #2: **

Using the same process as above, first define the variables required by the formula. In this case, these values are:

helix angle (deg) = 30

coefficient of friction = .76

Entering these values yields:

Elead = tan(30deg) / (tan(30deg + arctan (.76))) = 24.22 (%)