Gibraltar KN8C----B3S--21 Ball Knob 1.38 in Female Insert

Product Description

The GIBRALTAR KN8C----B3S--21 is a thermoplastic ball knob with a female insert mount designed for use on machinery, equipment panels, jigs, and fixtures across trade and industrial applications. The knob measures 1.38 inches in diameter and features a 1/2-13 threaded female insert for secure attachment to mating fasteners or threaded studs. Constructed from black thermoplastic, it provides a firm, comfortable grip in hand-adjustment and positioning tasks. The ball-style grip shape allows controlled torque application without tools, making it practical for frequently adjusted components. Weighing 0.4 pounds, the part ships individually and is available in single-unit quantities.

This ball knob is suited for light-duty manual adjustment applications in industrial, HVAC, and mechanical equipment environments. It is typically installed on panel-mounted threaded studs, machine levers, or adjustment screws where tool-free hand operation is required. The female insert thread configuration allows it to press or thread onto a protruding stud. The black thermoplastic construction resists common shop fluids and provides adequate durability for indoor mechanical use.

Key Features

• Female insert mount with 1/2-13 thread size for direct stud engagement
• Ball grip style allows controlled hand-torque without tools
• 1.38-inch diameter head for secure hand grip
• Thermoplastic construction in black finish
• Hub diameter of 0.75 inches with a hole depth of 0.55 inches
• Lightweight at 0.4 pounds per unit

Compatibility

Designed as a replacement or add-on female-insert ball knob for equipment and machinery using 1/2-13 threaded studs or fasteners requiring a hand-adjustable thermoplastic knob.

Installation Notes

Installation requires no special tools — the knob threads or presses onto a compatible 1/2-13 threaded stud by hand. Ensure the mating stud length does not exceed the hole depth of 0.55 inches to prevent bottoming out before the knob seats properly. Power down or de-energize any equipment before servicing panels or adjustment mechanisms where this knob is being replaced. Verify thread engagement is secure before returning equipment to service.