A The Gyratory Screen: 285 rpm, 2-1/2" horizontal circle dia. B. The Shaking Screen: 475 rpm, 1" stroke, zero pitch, 6 deg. slope. ... The Horizontal Vibrating Screen: 840 rpm, 1/2" stroke at 45°. Each has a .063" dia. wire screen with 1/8" clear opening, moving under a particle travelling at an assumed 20 fpm, for A, 40 fpm for B ...