4 Tips for Sharpening Blades with a Bench Grinder

A bench grinder on a white background.

A bench grinder is a useful tool for anyone who does a significant amount of woodworking or knife repair. A bench grinder has a grinding wheel that is spun at a very high speed. The grinding wheel can be used to trim off pieces of wood, plastic, or metal as well as to sharpen blades of all kinds. Many professional knife sharpeners will use a bench grinder to employ their craft. Getting a knife blade sharpened is often less expensive than purchasing a new blade. This is especially the case with chefs whose knives can cost several thousands of dollars. The following article will share with you some tips on getting the perfect sharpened edge of a blade using a bench grinder.

1. Never Use a Vice

Due to the high rate of speed associated with a bench grinder, it is often a gut reaction to use a vice. The vice will essentially keep the blade in one place as it is being ground down to a sharp edge. This is a gut reaction that should be avoided because sharpening a blade is not a linear process. In order to get a proper edge, the blade has to move naturally with the grinding wheel.

2. Proper Angle

A mistake that is often made is having the blade flat on the bench grinder wheel. You should never sharpen a blade with its side flush against the grinder. This will shine the blade up but not make it sharp. In order to get a sharp edge the blade needs to be angled toward the grinding wheel. A 20-degree angle is often the best angle to use when sharpening a blade.

3. Natural Movement

Most flat knife blades have a curvature to their form. When using the bench grinder, always follow the natural curve of the blade. As you are sharpening the blade the grinding wheel will automatically begin to pull the blade into it along this line. Do not fight the grinding wheel but instead follow it naturally. As you are holding the blade on the grinding wheel you should never have it in one place. As the grinding wheel will move the blade so should you. Do not fight the natural friction of the grinding wheel and the blade but control it. Move the blade along the grinding wheel in a very even and timed manner. This will allow the blade to get sharpened evenly.

4. Let the Bench Grinder Do the Work

The impulse of many first time users of a bench grinder is to put a lot of force into the blade as it is grinding. This is a mistake which can cause the blade to chip and you to lose control of the blade. The grinding wheel is spinning very fast and does not need your help to sharpen the blade. All you need to do is set the blade on the grinding wheel at the proper angle and let it do its work along the natural curvature of the blade.