Grit Size: Impact on the Grinding Process

Choosing the right grinding wheel for your application requires that you not only consider the material you are grinding, but also the processes you are implementing. Wheel speed, material removal rates, surface finish, and grinding equipment all play a role in the results yielded by your wheel. In order to select the ideal grit size, all of these conditions must be accounted for.

Differing grit sizes offer a differing range of cutting depth, material removal rates and surface finishes. Large grit sizes will remove more material, whereas finer grits will result in a better surface finish while not having the ability to cut as aggressively. Attempting to use a fine grit to produce an aggressive cut will not only prolong your grinding operation, but will unnecessarily wear the wheel’s grinding layer and significantly shorten its lifespan. Similarly, using a large grit size to obtain a tight tolerance grind will provide unsatisfactory results. Not only will it yield a rough surface finish, but maintaining tolerance will prove nearly impossible.

As mentioned previously, the lifespan of your grinding wheel can be adversely affected by utilizing a grit of inappropriate size. It is also imperative to ensure the wheel rim speed of your wheel is within the suggested range of 4500-7500 SFPM.

Wheel rim speed is calculated in surface feet per minute using the formula shown below. Using the correct running speed ensures optimal wheel performance.

SFPM = Diameter (in ft) x 3.142 x RPM