How to Choose a Blade

How to Measure the Overall Length of Your Blade

As shown, your blade must be measured from one sharpened tip to the opposite sharpened tip. This is a diagonal measurement across the blade. (Click to enlarge the image.)

Common blade measurements

Blade Term Definitions

Center Hole Diameter

This is the distance across the hole found in the center of the blade. Some blades will have a center hole pattern as shown below (click to enlarge the image):

Types of center holes

Mill Length

This is the length of the blade’s sharpened edge


This is the distance from the tip of the blade to the center of the blade mounting shaft. (See the “Common Blade Measurements” diagram above). Note: Not all blades have an offset.

Air Lift

The angle of the blade determines the amount of airflow and suction that is created when the blade is rotating.