A drill bit grinder is any machine specifically designed for sharpening drill bits. Since these bits are made from metal, the only method for sharpening them is using a type of grinder, which is why the terms drill bit grinder and drill bit sharpener are often used interchangeably. Machines that are made for the sole purpose of sharpening drill bits are usually called drill bit grinders. Industrial size grinders intended for drill bits are larger than those used in a home workshop; therefore, manufacturers offer smaller drill bit grinders specifically for the do-it-yourselfer. Most drill bit grinders will handle a range of drill bit sizes, from the common sizes found around the home to the large industrial sizes that most individuals will never see or use.
Numerous types of drill bits are available, but not all require the same type of sharpening. For example, drill bits designed for drilling wood have a slightly different angle ground onto the points than drill bits designed for masonry or concrete. Different applications require different types of drill bits, and each type typically has a different shape.
Sharpening a drill bit by hand, without the use of a specially designed drill bit grinder, can be extremely challenging. Some individuals actually can perform this task by hand, but it often takes years of practice to gain precision. When drill bits are not sharpened properly, they have a tendency to “walk,” which means the drilled material is left with oblong shaped slots, instead of round holes. Additionally, improperly sharpened drill bits may not cut or drill at all.
By using a drill bit grinder, one can achieve a precisely-sharpened point that will perform as expected. What makes sharpening such a challenge is achieving the proper angles on the end of the drill bit. A drill bit sharpener is designed to hold the drill bit against a grinding wheel at the desired angle, every time. Maintaining the proper angle is crucial for producing a sharp drill bit. In contrast, improper angles can result in drill bits that simply do not cut into the material being drilled.
Common solutions in the past for dull drill bits were to either replace them with new ones or contact a machine shop where skilled individuals could sharpen bits at a cost. Today, the average do-it-yourselfer can purchase a drill bit grinder that will handle most common drill bit sizes, for relatively little money. One can weigh the costs versus the convenience to determine the best choice in a given situation.