Countersink Diameter Calculator

Calculate Countersink Diameter



Formula

The formula to calculate the Countersink Diameter (CD) is:

\[ CD = \frac{S}{\cos\left(\frac{\theta}{2}\right)} \]

Where:

What is a Countersink Diameter?

The countersink diameter is the diameter of the conical hole cut into a manufactured object to allow a screw to be flush with or below the surface of the material. The countersink diameter is larger than the screw diameter and is determined by the screw size and the countersink angle. This measurement is critical for ensuring that the screw fits properly and that the surface is smooth after the screw is installed.

Example Calculation

Consider an example where:

Using the formula to calculate the Countersink Diameter:

\[ CD = \frac{0.25}{\cos\left(\frac{90}{2}\right)} = 0.354 \]

This means that the countersink diameter for this example is 0.354 inches.