20 Types of Drill Bits: And What They Do

It depends on the job. Titanium bits are HSS bits with a coating that reduces heat, making them great for general metal drilling, but they lose their benefit if sharpened. Cobalt bits are made of a steel/cobalt alloy through and through. They are harder, more heat resistant, and can be sharpened, making them the superior choice for tough stainless steel, though they are more brittle.

If you drill through hard metals like cast iron or stainless steel often, yes. They will last much longer than standard bits. However, for general DIY tasks involving wood, plastic, or soft aluminum, standard HSS or titanium bits are more cost-effective and less likely to snap.

Colors often indicate material or coating. Black usually means black oxide (standard HSS). Gold typically indicates a Titanium Nitride coating (good for heat). dull silver or gray is usually Cobalt (for hard metal). Bright silver is often standard steel or aluminum. Note that some cheap brands use paint to mimic these coatings, so always check the packaging specs.

Carbide is the hardest material used in drill bits. You usually find it as a tip on masonry bits or as the main body of industrial metal bits. It is extremely heat resistant and stays sharp longer than steel, but it is very brittle. It is generally reserved for masonry, tile, or high-speed industrial production.

This refers to the angle of the tip. A 118-degree point is the standard angle for general-purpose drilling in wood and soft metal. A 135-degree point is flatter, which allows more of the cutting edge to engage with the material sooner. 135-degree split-point bits are better for drilling into harder metals and prevent the bit from walking.

For light metals like aluminum, standard HSS bits work fine. For steel, Titanium Nitride (gold color) is better. For hardened steel or stainless steel, you need Cobalt bits (usually 5% or 8% grade). Always use a slow speed and lubricant when drilling metal.

For general holes, standard twist bits work. For clean, precise holes, use Brad Point bits. For large rough holes (like running wire), use Spade bits. For deep holes, use Auger bits. For flat-bottomed holes (hinges), use Forstner bits.

Look at the tip. Concrete (masonry) bits have a distinct wide head that looks like an arrowhead or a small roof, usually made of tungsten carbide. The shank may also be slotted (SDS) rather than smooth. If the tip looks like a simple sharp point or spiral, do not use it on concrete.

PDC stands for Polycrystalline Diamond Compact. These are industrial-grade bits used primarily in the oil and gas industry for drilling through deep rock formations. They feature synthetic diamond cutters that shear rock away rather than crushing it.

Solid Carbide bits are technically the hardest and “strongest” in terms of wear resistance, but they are brittle. For toughness (resistance to snapping) combined with cutting power, Cobalt alloy bits are generally considered the strongest and most durable for the average user or tradesperson.

Bit slipping, or “walking,” usually happens on smooth surfaces like metal or tile. To stop it, use a center punch to make a small dimple in the material before you start drilling. Alternatively, use a “split point” drill bit which is self-centering, or place a piece of masking tape over the area to give the bit some grip.

Yes, High-Speed Steel (HSS) and Cobalt bits can be sharpened using a bench grinder or a dedicated drill bit sharpener. However, Titanium coated bits should generally not be sharpened, as grinding them removes the gold heat-resistant coating that makes them effective.