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There are a lot of ways to make holes in wood, but if your goal is efficiency and accuracy, grab a drill with the right size bit. While you might think all drill bits are the same—spin real fast, make a hole, right? The truth is that drill bits come in a variety of materials and with different tips designed for specific projects. You should also think about how many bits you need when purchasing a set; some include just a few, while others come with more than two dozen. And, of course, there’s always the question of your budget—having more than 20 drill bits might be nice, but maybe you don’t need them all if the purchase is going to break your bank. Below, we explain the ins and outs of drill bit sets, and offer up some examples of ones we like.

Irwin Tools


Drill bits are designed for use with a variety of materials, but they might handle some better than others. Whether a bit can cut through soft wood, hard wood, tile, glass, or stone is determined by its hardness and the type of cutting edge.

Soft low-carbon steel bits are the least expensive, but they can lose their sharpness quickly. They’re ideal for softer woods, like balsa, which makes them excellent for hobbyists and modelers who might want to save some money.

Harder high-carbon steel bits, on the other hand, work with both hard wood and metal. But be careful—they can lose their cutting edge if they heat up too much.

Because of their weaknesses, carbon steel has been mostly replaced in drill bits by something called high-speed steel, or HSS. It’s resistant to heat, making it great when working with hardwoods and metal.

Another choice are cobalt steel alloys, which can hold their hardness at high temperatures, and can even drill through stainless steel. However, this material is more brittle than HSS.

Finally, there’s tungsten carbide. This expensive material is often used on the tips of drills because it can go through most materials without losing its edge. These make great bits for use with stone tiles.



You might notice that not all drill bits are silver colored. That’s because they often feature coatings designed to increase longevity.

Black Oxide helps avoid corrosion and reduce friction between the bit and the material being drilled, and also assists in moving cut material up through the bit’s fluting. Unfortunately, the bit can start to dull as the coating wears away through use.

Titanium nitride is a similar coating, but, besides rejecting corrosion, it also increases surface hardness and decreases the effect of heat. This means your bits last longer and can cut through harder woods and metal. However, they’re not great for concrete and masonry. And again, the material can wear away over time.

Cobalt drill bits are made from an alloy of five percent to eight percent cobalt that’s blended in with the steel. This means it won’t wear away like black oxide or titanium—it’s in the bit itself. They’ll drill through most anything, and you can get them sharpened. However, expect a higher price tag for these bits, which is why many professionals use softer bits for wood and plastic, and keep cobalt bits in reserve for harder metals.



When most people think of drill bits, they think of twist bits—fluted, sharp-edged rods of metal with pointed tips. These common bits can tackle wood, metal, glass, tile, and most other materials, but they work best when the hole you need is ½-inch in diameter or less. Anything wider than that requires some more specialized bits.

Spade bits are cost-effective, paddle-shaped pieces that throw out chips of wood rather than carrying it up through the flutes. They can drill much wider holes than twist bits, but only work with wood. Auger bits, which resemble spade bits, drill deeper and feature a threaded tip that pulls the bit forward as it rotates. Step bits are designed for sheet metal, and do an excellent job of making or enlarging holes without deforming the material. However, they’re limited to drilling through materials ⅛-inch or less, and often cost a lot of money.