Abstract: A system for screening particulate material includes replaceable screening modules mounted to a rigid frame by lock pins. The lock pins are fixed into mounting holes in the frame and interlockingly and removably engage recesses in the sidewalls of the screening modules so that the lock pins remain fixed to the frame while allowing the modules to be removed and replaced as required due to wear or to change sieve size. A split lock pin is provided for removably connecting the module to the frame along an outboard edge of the frame while maximizing screening area. An improved elongate frame member is arranged to avoid abrasive wear of the frame.