Thumb Screw Thumbscrew Black Thumb Screws Stainless Steel Standard Coarse Threads Clamping Rosette Knobs Thumb Screw Specification: Thread Diameter: M4 Screw Length: 30mm Fully Threaded: Yes Minimum Thread Length: Full Thread Material: Corrosion Resistant Carbon Steel Knob Specification: Knob Style: Knurled Round Knob Color: Black Knob Material: High Quality Plastic Wide Applications Clamping knurled knobs universally fit most types of machine tools. Can be used for milling machine, lathe, grinding machine, mechanical equipment, instrument, and industry equipment. Knurled Knobs Black clamping knurled hand knobs. It is sturdy and durable. Provide comfortable hand grip. Screw on type design for easy installation. Great replacement accessories for your lathe. Lathe Accessories A wide variety of lathe accessories are provided: Ball Knobs, Star Knobs, Knurled Knobs, Lever Handles, Revolving Handles, Hand Wheels and so on. They are universal use and suitable for your lathe machines. Please pay attention to the measurement to make sure it is right for you before ordering.