Drill Bit Sets: What Every Homeowner Needs in the Drawer

What is a drill bit set?

A drill bit set is a case of twist drill bits, the spiral-grooved cutting tools that fit into a drill's chuck and cut a round hole. The set comes in graduated sizes, so you can pick the bit that matches the hole or screw you need. Most general-purpose sets run from about 1/16 inch up to 1/2 inch.

Each bit has three parts you should know:

• The tip. It does the cutting. A split point has a small notch at the tip that helps the bit start without wandering.
• The flutes. The spiral grooves carry chips and dust out of the hole.
• The shank. The smooth end that sits in the drill's chuck. Some shanks have flats so the chuck cannot spin on them.

Most cordless drills are sold with no bits at all, which is why a bit set is among the first things a new owner buys. Larger sets, such as 29 pieces, contain every size in small steps, so you never have to hunt for an in-between size.

How bits differ

Three terms show up on almost every box:

• High-speed steel (HSS). The standard material. It drills wood, plastic and soft metals well.
• Black oxide. A dark finish on top of HSS that helps resist rust and keeps the bit from sticking.
• Titanium nitride and cobalt. Titanium nitride is a gold-coloured hard coating. Cobalt bits are made from a harder steel alloy that resists heat, and they suit stainless steel and other tough metals.

For wood, plastic, drywall and mild steel, HSS bits do the job. That is why a good HSS set is the first one to buy.

Why you'll want one

You can't hang a shelf without a hole. Anchors, hinges, hooks and curtain rods all need a hole of the right size. The right bit makes a clean hole in seconds.

It prevents split wood. Driving a screw into the end of a board or near its edge splits it. A small pilot hole first makes the screw go in cleanly and hold better.

It saves screws and bits. A pilot hole means less force, so you strip fewer screw heads and break fewer driver bits.

It lets you use the right size. Without a full set, you end up using a bit that is too big or too small. Too big a hole makes anchors spin. Too small a hole splits wood.

Metal, too. A sharp HSS bit drills thin steel, aluminum and brass, which comes up in repairs, brackets and cabinet hardware.

What the tests say

Project Farm tested drill bit sets in two videos, drilling mild steel, spring steel and, in the newer test, armor plate:

• In the older test, an inexpensive DEWALT high-speed steel set was one of the fastest bits through mild steel and a "great value" pick for occasional use on softer metals. It wore faster in hard spring steel, and he recommended a Bosch cobalt set as the best value for harder metal.
• In the newer test, the same type of DEWALT HSS bits were slower. An inexpensive cobalt set finished first overall, and only a few sets drilled through the armor plate.
• Pilot-point bits cut very fast, but the reviewer noted they are difficult to sharpen.

What this means for a homeowner: a basic HSS set is fine for wood and light metal, and a cobalt set earns its place only if you drill a lot of hard steel. The tested DEWALT bits were a 14-piece set, while the set we feature has 29 pieces, but the listing states the same basic features: high-speed steel, a 135 degree split point and a 3-flats shank.

How to use it

Read your drill's manual first. These steps are the routine most safety guides teach.

1. Choose the right bit. Use a twist bit for metal, plastic and wood. Pick a bit about the size of the screw's shaft (not the threads) for a pilot hole.
2. Put on safety glasses. Drilling throws chips, and a bit can snap.
3. Clamp the work. Never hold small pieces in your hand. A bit that catches can spin the piece into your fingers.
4. Mark the spot. Use a pencil on wood. On metal, tap a center punch or a nail to make a dimple so the bit does not walk.
5. Insert the bit fully. Tighten the chuck by hand, then give it a final firm turn so it grips the shank, not the flutes.
6. Start slowly. Squeeze the trigger gently until the tip bites, then increase speed. Use low speed for large bits and metal, and high speed for small holes in wood.
7. Push steadily and straight. Keep the drill level with the work. Let the bit do the cutting, because heavy pressure overheats and dulls it.
8. Clear the chips. On deep holes, back the bit out now and then to clear chips and let it cool.
9. Ease off at the end. Reduce pressure as the bit breaks through, so the back of the board does not splinter. A scrap board behind the work helps.
10. Use cutting oil on metal. A few drops cool the bit and make it last longer.
11. Unplug or remove the battery before changing bits. It prevents accidental starts.

Tips for cleaner holes

• Drill a smaller pilot hole first for any large hole in metal. Step up in size.
• Use a depth stop or a strip of tape on the bit to mark how deep you want the hole.
• Slow down in metal. Too much speed burns the bit, which is a common reason a bit stops cutting.
• Wipe and re-case your bits. A dry bit in its slot stays sharp and rust-free.

Common mistakes

• Pressing too hard. More pressure does not cut faster. It heats the tip and dulls it.
• Running too fast in steel. A bit that is blue or smoking is burnt.
• Skipping the pilot hole. Screws driven into dry hardwood without one split the wood or snap the screw. See our screw assortment guide for sizes.
• Using the wrong bit. A twist bit in brick or tile only overheats. Use the right bit for the material.

What to look for when buying

Number of pieces. A 29-piece set covers every 64th of an inch from 1/16 to 1/2 inch. Smaller sets, such as 14 pieces, skip some sizes and save money. For a first set, the larger one avoids frustration.

Material. HSS is the standard and is enough for most homeowners. If you drill stainless steel or hardened metal, look at cobalt, but expect a higher price. Project Farm's results showed that cobalt is not always better, so read the reviews on the specific set.

Finish. Black oxide helps resist rust, and titanium nitride gives a hard surface. Neither turns weak steel into strong steel, so do not choose on colour alone.

Point style. A 135 degree split point starts without a punch mark and works well in metal. Pilot-point bits are fast but harder to sharpen.

Shank. A round shank fits any drill. A 3-flats shank resists slipping in the chuck. If you use an impact driver, look for a hex shank.

Case. A hinged case with clear size markings is much easier to live with than a loose pile of bits. It also protects the cutting edges.

Warranty and brand. Brands such as DEWALT, Bosch, Milwaukee and Irwin are common choices, and they are widely sold. Check reviews for the specific set, because quality can change from one year to the next. Project Farm's own results shifted between his two tests.

The table below sums up the key specs you can use to compare sets side by side.

Key specs to look for

Where to get it

For this guide we are featuring the DEWALT 29-piece black and gold drill bit set. According to the listing, it is made of high-speed steel with a black oxide finish, a 135 degree split point, a tapered web for durability, a 3-flats shank and size markings on the shank. It sits in our budget tier, and it comes from a long-established brand with a lot of buyer feedback.

DEWALT 29-Piece Black and Gold Drill Bit Set (DWA1189)

Budget ($)Worth-owning score 8.3/10

• A 29-piece set of high-speed steel bits in graduated sizes, per the listing
• 135 degree split point and a 3-flats shank to help prevent walking and spin-out
• A black oxide finish to help prevent rust and wear

View on Amazon

How we scored it

Usefulness 9/10 · Value 9/10 · Durability 7/10. This is our own opinion, based on specs, buyer reviews and independent tests. It is not an Amazon or customer rating.

If you drill a lot of hard steel, add a single cobalt bit in the sizes you use most. Check the current listing and read recent reviews before you buy. Whatever you choose, pick up safety glasses and a small center punch the same day, and if you do not own a drill yet, see our circular saw guide for what to buy after it.