— A jaw crusher size is obtained by looking at its feed opening (gape) and length. As an example, a monster 7959 of 79″ x 59″ (2m x 1.5m) will have its fixed jaws 79″ apart where the feed enters on a 59″ wide set of liner plates. The factors list below will enhance crusher capacity and performance: 1. Proper selection of the jaws.