PennEngineering® Large Knob, Spring-loaded - Types PF11MF and PF12MF - Unified PF11MF-440-1

The PF11MF-440-1 is a large knob, spring-loaded, flare-mounted captive panel screw designed for close centerline-to-edge applications and installation into any panel hardness. It features a shoulder on the retainer for positive stop during installation and an anti-cross-threading design. The screw has a #4-40 thread, hardened carbon steel body, aluminum retainer and knob, and a zinc-plated finish per ASTM B633. Installation requires a countersunk hole with a nominal diameter of 0.112 inch and a minimum sheet thickness of 0.041 inch. The retainer flares to secure the fastener, with a minimum float of 0.010 inch in all directions. The drive type is Phillips, and the knob has a knurled metal cap. The retainer pullout force is 81 lbf, and the installation force is 250 lbf.