Sharpen Drill Bits In A Pinch Without Power Tools Or Grinders

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I've been a woodworker and remodeler for 25 years, and while some argue that a dedicated tool is the best way to sharpen dull drill bits, I still often turn to other options. When I'm in the workshop, for example, I sometimes use a bench grinder, since it has a rest that helps me keep the bit at the right angle, and I can use the same machine for sharpening my chisels and even my lawn mower blades. However, if I'm away from the workshop and I discover a blunt drill bit, I'm going to need to do the job by hand. In a pinch, I can use aluminum oxide paper.

It's commonly called sandpaper, although it doesn't contain any sand. Technically, it's an abrasive paper, and is what you use for refurbishing furniture or finishing beginner woodworking projects. While it might not seem substantial for sharpening a steel drill bit, it absolutely can do this, too. Aluminum oxide is actually the same stuff many grinding wheels are made from. In this case, it's bonded to paper.

When it comes to sharpening your drill bits, 80 grit is a good choice, and there are a couple of techniques to try. Some people wrap the abrasive around a file and rub that against the end of the drill bit. I find it difficult to apply enough pressure and maintain the correct angle with this method. Instead, I wrap the abrasive around a piece of plywood or hold it against a hard, flat surface and rub the drill bit across it. When doing this, be sure to turn the drill bit every few strokes to sharpen both cutting edges. This strategy might not be the most effective or ideal, but it does the job when you have no alternative.

Ordinary twist drill bits are made from high-speed steel, which is quite hard and very affordable. Aluminum oxide works fine to sharpen those. However, some top-rated drill bit sets can include drills that are made from much harder materials. There are cobalt, titanium, tungsten carbide, and even diamond-tipped versions available, and aluminum oxide won't even scratch them. In fact, even on a bench grinder, you'd need a special wheel to sharpen these.

A number of drill bits also come in less common shapes. A paddle bit (also called a spade bit) has a central spur to guide it. My preferred technique with aluminum oxide will just about work, but it can feel awkward because of this. There are also hole saws, saw-tooth bits, and forstner bits that have sharp teeth or circular blades for cutting. Sharpening these requires a different approach.

All of these bits can still be sharpened without power tools or grinders, but not with abrasive paper. Instead, you need diamond-encrusted files. The EZE-LAP Forstner Bit Sharpening Kit includes flat and triangular files that can be used to sharpen a variety of bits and, at around $25 at the time of writing, is well worth the investment if you use these types of drill bits often.