There’s a couple ways to go about this, with a fair number of people preferring either method.

One is the physical discharge setting method. This is done by passing a compressible material such as a lead slug or aluminum can through a running empty crusher and measuring the thickness of the passed test material. The crusher is then locked at a physical closed side setting that provides the desired finished material size.

Another method that’s becoming more common is setting the discharge close to what’s anticipated as the desired setting on a physical basis, and then running it full of material to be crushed. The crusher is adjusted either open or closed, until the desired discharge product is obtained. The power requirement in ampere draw is noted and the crusher is run at that rate until the finished product size changes due to liner wear and the amp figure needs re-evaluated. This method is common among jaw, cone and roll crushers.