Note - Always tighten the thumbscrew knob securely to prevent any movement of the fixed assembly. Do not over-tighten the knob as this may damage or strip the threads in the mating assembly. Replace the knob if necessary. Applications - Thumb screw knobs with hand bolts are commonly used in applications that require frequent and quick adjustments or tightening. Widely used in lathes, drill presses, packaging and woodworking machinery, printing and industrial equipment, and fixtures. Material - Zinc plated carbon steel threaded studs on knobs ensure durability, strength, functionality and wear resistance. Premium plastic clamping knobs provide durability, a smooth surface and comfortable grip. Features - The tightly-in metal insert are machine-injected at high temperatures to securely the parts together, easy to install. T wing knobs are easy to grip and turn by hand, providing leverage and comfort, making it easier to tighten or loosen the knob. Size - Standard Thread Size: M6 (1mm Pitch); Thread Length: 35mm / 1.38"; Tee Wing Head Width: 36mm / 1.42"; Total Length: 48mm / 1.89"; Knob Style: Tee; Color: Black ( The threads are neat and clear, the force is even and deep, not easy to slip, and there are no burrs.)