If the material is a regular grade of round steel, otherwise the surface of the workpiece is likely to form scales, etc., the milling cutter is easy to be damaged and cracked, and the knurling tool wears quickly. If the gap is too large, the workpiece will have to tilt the hob wheel, and the rolling pattern will be uneven, and the knurling knife itself will be easily damaged; the pressure plate should try to seal the knurling knife to prevent splashing of chips, debris, etc.; do not lubricate when working Cool the knurling cutter to prevent damage to the carbide blades close to it. First start the lathe to rotate the workpiece, and then tighten the screw to prevent excessive static friction and slippage of the workpiece; the trapezoidal screw is reduced by using a well-made knurling cutter For the number of tool changes, remove the quick-change cover regularly to clean the tool slots.