August 1, 2017 by SteelWolfKnives
Tool Spotlight – Belt Sander
Remember in the Angle Grinder Tool Spotlight when I said that it was the most versatile and most used tool for a new knife maker? Well the belt sander (also called a belt grinder) gives it a run for its money. In this article, I will be comparing the two quite often. While it can’t cut fine lines or move around easily, the belt sander is versatile in ways the angle grinder is not. It can work with several different materials, has many different kinds of grinding, and is easier to control than the angle grinder.
One of the drawbacks of the angle grinder is that it only runs at one speed and one size. It isn’t easy to fine tune how aggressively it removes material. On steel that doesn’t matter as much since it is pretty hard and the grinder has to be aggressive to remove much material at all. On other materials though, that might not be the case. If you want to work with handle materials the angle grinder will burn or melt them. The belt sander can work on wood and G10 without destroying them. A variable speed belt sander is ideal since you can further change it to suite exactly what you want it to do, but even a fixed speed sander will work. When you use a belt sander, you hold the knife against the sander instead of the angle grinder against the knife. Since you are holding something that is lighter and smaller, it is easier to control the exact angle and pressure you apply, making the work more precise and less tiring. This is true for handle working, but also for the bulk of stock removal. What could take three hours with the angle grinder may only take one with the belt sander.
You have tons of options in terms of belts, from 20 grit (to do really rough shaping) all the way up to the equivalent of 12,000 grit and higher. There are different kinds of materials in the belts as well. Aluminum oxide is the most common and cheapest, but it wears away after 3-4 knives. Ceramic costs more for each belt, but in my experience, they last about 2.5 times as long and feel nicer to use. There are even Trizact belts, which have a different grain structure to run cooler and longer. While belts for the belt sander can vary in length depending on the size of sander, most are the same shape. Unsurprisingly, this shape is one of a belt, or a continuous loop with straight sides. These are really good at creating crisp lines (like where the bevel stops before becoming the handle) and are by far the most common belt. The other shape of belts that are useful are ones that have a “feathered” edge. Instead of the hard edge of the normal belts, the feathered edge has more of a chevron pattern as seen here. These belts are ideal for blending different angles together, as well as for rounding handles.
There are several lengths of belts designed for different sanders. The best length is the one that fits your belt sander. But if you are looking to get a new belt sander or don’t currently have one, the go-to for knife makers is a 2in x 72in belt. The 2×72 is nice because it is long, it is a standard size, and easily usable for everybody. There are two reasons that longer belts tend to be better. The first is that longer belts stay cooler when grinding because they have more surface area. More surface area means that as the belt rotates around, the part that touched the metal has longer to cool down before it touches the metal and heats up again. The second reason that they tend to be better is also because of surface area. Because it has more surface area, each part of the belt gets used less than any part of a shorter belt. This causes it to wear slower and therefore last longer. However, longer belts (and the accompanying sanders) are more expensive and take up more space in your workshop. Longer belts are also more expensive and harder to find. A 2inchx72inch setup is a very good compromise.
You can find more information about the different attachments for a belt sander here.