Employee
Knurling is a method used to cut or roll a pattern into a material such as plastic or metal. This process is normally done on a lathe, although in some cases a manual knurling tool is used. A sawn object can have a diamond, cross, or straight line pattern that adds functionality and a pleasing aesthetic. Knurling is often intended to provide a better gripping surface than the raw material, and knurling patterns are often found on handles, buttons, and other similar items. Another use for the process could be putting a worn part into service, for example, as the piston skirts of internal combustion engines used to be knurled to increase performance.
The main method used to knurl objects is a lathe process that uses a very hard roller to press the desired shape into the work material. A roll with a reverse impression of the desired protrusion is clamped on a joint or jig and then pressed against the workpiece. The main configurations used for this type of knurling contain one or two rollers. A straight notch can be pressed with a roller, but any type of diamond or cross pattern will require rollers with opposing patterns. The disadvantage of this process is that the rollers must be adjusted to the unique outside diameter of each part, making it better for mass production of many identical components.
Another lathe process is similar to that used to cut screw threads. This method can be used to create a diamond pattern by essentially cutting the left and right strands on the same object. In this case, the knurling process is usually accomplished using a self-feeding lathe and a variety of cutting attachments. Unlike the rolling method, a single cutting attachment can be configured to knurl a wide variety of different workpieces.
A third way to knurl an object is with hand tools. These hand knurling tools work the same way as pipe cutters, but are designed to press a pattern into the workpiece instead of cutting it. Most hand knurling tools contain three wheels, one of which will have an opposite pattern to the other two. The benefit of this process is that the required tool can usually be brought to the job site instead of taking the part to a large stationary lathe.