Most of us are guilty of using the wrong tool for the job—either out of necessity or laziness. Still, there’s something satisfying about using the right tool for the job. Often, using the right tool helps bring about the best possible result. When drilling, accessories matter—possibly even more than the tool you choose. Knowing the various types of wood drilling bits and how to use the right one can really increase both speed and quality.
Knowing the Many Types of Wood Drilling Bits
Before we get to drill bit types, you should be familiar with the various treatments drill bit manufacturers use to increase bit life and reduce friction. Drill bits are made from steel, high-speed steel (HSS)—which is steel alloyed with tungsten and/or molybdenum, HSS with a cobalt alloy, HSS with titanium coating, HSS with black oxide coating, or carbide tipped.
Drill bits appropriate for wood drilling are steel, HSS, titanium coated, and black oxide coated. Those other bits work best for metals. We’ve written about black oxide coating and have reviewed the best drill bits as well as the best drill bits for metal.
Some Tips Before You Begin Drill in Wood
Know the General Wood Type
Wood species are divided into the two general categories of softwoods and hardwoods, but there is also much hardness variation within those categories. The wood type makes a significant difference in bit choice. Drilling a soft pine will be much easier on a drill bit than drilling a hard hickory. You can drill softer wood with steel (although we’d recommend HSS for any job) but as the hardness increases, it must be matched by bit hardness. This means a titanium or black oxide coating is appropriate for hardwood.
What Type of Hole is Needed?
The purpose of the hole affects bit choice. Will the hole accommodate an anchor to hold a picture, will it be used for wire or conduit, does the fastener that goes in it need to be countersunk?
The Major Types of Wood Drilling Bits
Twist Drill Bit
This is the type of bit that probably comes to mind first when you hear “drill bit.” It’s the most common type of bit and used for general purposes around the jobsite and home. Softwood can get stuck in the flutes, so gently remove it with a brush or by blowing it off.
As we mentioned above, twist drill bits (or “twist bits”) can range in price from affordable black oxide coated bits to expensive carbide bits used in milling. When it comes to choosing a drill bit for your wood project, a nice set of high-speed steel (HSS) bits should do just fine.
Brad Point (Bradpoint) Wood Drilling Bit
This wood drilling bit’s distinguishing feature is in the name. The sharp point on a brad point bit helps position the bit for a precise hole. These bits don’t walk on you when you start a hole. This makes this the right wood drilling bit for when you need a truly accurate start.
Spade bits have a broad, flat area for boring larger diameter holes in wood. The spade bit has no flutes so you may have to back off the bit as you go when drilling deeper holes. While a traditional spade bit has a perfectly flat face, products like the Bosch Daredevil spade bit feature a self-feed tip and a slightly curved face.
You’ll immediately notice a threaded tip on auger bits. This type of wood drilling bit uses the tip to quickly pull the bit through the wood. Auger bits maintain a constant flute throughout the length of the bit. These bits challenge cordless drills because they “force” the drill to maintain speed throughout the hole due to the self-feed tip.
Often confused with a Forstner bit, self-feeding bits include a threaded tip like the auger bit. This pulls the bit through the wood. These bits are meant for holes that go all the way through the wood. This is exactly the right type of wood drilling bit when you want to make a lot of larger holes for rough-in. Typically, self-feed bits are used for boring larger holes.
Self-feed bits can be a tad more aggressive than other large-diameter wood bits. They can also use either one or two cutting heads in addition to the perimeter cutting teeth. Check out our review of the Milwaukee self-feed bits and the Diablo SPEEDemon self-feed bits.
Installer Bits (Also Bell Hanger or Fishing Bits)
Just as the name implies, these long, skinny “bell hanger” wood drilling bits are used for electricians pulling wires or performing similar installation work. In addition to their long length, installer bits often feature a hole near the front of the bit for use with pulling wire.
A related bit to the installer bit is the flex bit which just uses a flexible shaft to let you get into tight spaces as needed. These can exist in lengths up to 72-inches.
These bits perform double duty as they drill a pilot hole and countersink the hole at the same time. This ensures that the fastener head sits just below the surface of the wood.
These odd-looking bits bore through wood or create flat-bottomed holes if the hole doesn’t go all the way through the piece. Use them when setting up cabinet hinges or similar applications.
A hole saw uses a pilot twist bit to guide a large diameter rotary saw that removes a plug from the wood. This allows conduit or wires to pass through. You also use these bits when drilling out locksets for doors. You can find hole saws for both wood and metal.