A knurling is a tool that is attached to a lathe to perform diamond patterns and straight knurling. It is used for processing the anti-rotation and anti-slip of handle parts. Depending on the processing method, there are two types, a cutting type and a rolling type. The cutting type has a relatively small load during processing, reduces the load on the machine, and improves the accuracy maintenance management. Some products have a small rise in outer diameter and can be processed with copper alloys, aluminum, resin materials, etc. that are difficult to handle conventionally. The rolled type is inexpensive and can be processed in a relatively short time by applying pressure. In addition, there is a rolled type product that can be automatically aligned with an auto slide mechanism to reduce misalignment. It is necessary to select the knurling after confirming the size of the holder, the type of the compatible piece, and the pitch of the piece.