A die grinder is a tool used to polish and buff the surface of various objects. They use attachments, much like drill bits for a drill, that are connected to the grinder by a collet, which is a small cylindrical holding device. Though die grinders are most often associated with cutting or smoothing metal, some can also be used on plastic and wood. They come in a variety of sizes, and can be either straight or angled.
Die grinders can range in size from a small handheld versions to bench top models. Many die grinders are air powered, but there are also electric versions available. When choosing a grinder, it is important to consider its primary purpose, what attachments must be used, and the amount of time that will be spent grinding down materials. An incorrectly used die grinder can wear out quickly and cause injury to the operator.
All die grinders have Rotations Per Minute (RPM) ratings and no-load speeds. RPM measures how often the grinder spins while in use. No-load speeds refer to the rotations of the tool’s spindle when it is idling. If the RPM rating is higher than the no-load speed, the die grinder could shatter upon use. The grinders RPM rating must also not exceed the RPM rating of the attachments used, as this could cause the attachments to break or shatter.
A die grinder's RPM rating may also determine the types of jobs it's best suited for. For instance, a die grinder with a high RPM may be better suited for polishing, while one with a lower RPM may be more suitable for heavy-duty grinding. This is because lower RPM grinders tend to have a higher horsepower, and thus more torque.
When running a die grinder, it is important to follow some simple safety rules. Never wear loose jewelry while operating the grinder. Neck chains can easily become caught in the grinder and cause strangulation. Safety goggles should also be worn at all times.
The operator must keep a strong hold on the grinder at all times. Similarly, the component being ground should be held in a bench-top vise or clamp. Fingers should be kept out of range of the die grinder. When the die grinder is not in use, it should be unplugged.