PT 36642 Foot Pedal Switch Fits SDT 300 and RIDGID &reg; 300 535 Threading Machine PT is a realistic alternative for Ridgid  300 parts Footswitch for Ridgid  300 and Ridgid  535 pipe threading machines. Replaces Ridgid  part: 36642 B296. Foot Pedal for Ridgid  1224 and Ridgid  15682. Hard Wired Replacement Foot Pedal Assembly.