How to Drill a Pilot Hole

To an inexperienced DIYer, drilling pilot holes can seem like a waste of time and effort. You have to drill every hole two times, effectively doubling the amount of work. But without a pilot hole, the threads of a screw can act as a wedge, forcing material apart.

Repairing damage caused by drilling without pilot holes takes longer than drilling the holes themselves. Avoid frustration by learning how to drill pilot holes in any material. 

How to Drill Pilot Holes

Drilling pilot holes isn’t hard, but there are a decent number of steps in the process.

1. Choose a bit for the pilot hole. To guide your decision, compare your drill bits to your intended screw. Select a bit that is the same diameter as the tip of the screw. The pilot hole should be as wide as the body of the screw minus the threads. The bit you use to drill the pilot hole should match the material you’re working with. A carbide-tipped masonry bit will work well for mortar, brick, clay, or concrete. For stainless steel, choose an HSS (high-speed steel) or cobalt bit. Standard steel drill bits are appropriate for wood. A diamond-core drill bit is best for making holes in stone. 
2. Insert the bit into the drill and tighten the chuck. Set the depth guard to the exact length of the screw. If the screw encounters resistance at the bottom of the hole, the twisting and cracking you’ve worked so hard to prevent may occur. If your drill did not come equipped with a depth guard (a metal rod that dictates how far the drill can penetrate your work material), you can improvise one instead, using the directions in the following step. 
3. A piece of painters tape or masking tape wrapped around the drill bit will help you verify the pilot hole is the correct depth. An alternative method of controlling pilot hole depth is to drill all the way through an appropriately-sized piece of wood. This make-shift block is a nearly foolproof way to drill pilot holes to the perfect length. When the wooden depth guard meets your work piece, it’s time to stop drilling. This is particularly effective if you have many pilot holes to drill. 
4. Mark the spot where the fastener will go. You can use a nail to indent most surfaces, giving you a visual and tactile reference to guide your drilling. Some materials, particularly wood, may benefit from a few strips of painter’s tape to support and protect the material as the screw is forced into it. Painter’s tape on stainless steel prevents heat-related discoloration. Put on a respirator if you are drilling into materials that release silica dust, such as concrete. Goggles are recommended. If possible, clamp the workpiece directly to a sturdy surface to avoid it spinning out of control. 
5. Connect your drill to power and check that the toggle switch is flipped to ‘forward’. Place the tip of the bit into the indent you made in the previous step. Square your shoulders and plant your feet. Be prepared for the drill to push back against the arm that holds it. You can use your opposite hand to provide gentle resistance. Squeeze the trigger gently. Once the tip of the bit is no longer visible, use an appropriate speed for the material you’re working with. For concrete, tile, metal, stucco, or glass, a slow and steady speed is best. Drilling into wood or plywood is best done at a higher speed. 
6. Plunge the bit into the surface material using minimal pressure and no force. Ideally, the bit and drill will do the majority of the work. If you encounter skipping or lagging, back the drill out of the hole and try again. When working with wood, you may encounter knots and irregularities that make drilling difficult. Concrete usually contains rebar, which could break your drill bit if you’re not careful. 
7. When you reach the desired depth, back the drill out of the hole. When it has cleared the exit, release the trigger and allow the drill to stop spinning before you set it down and disconnect it from power. Use a vacuum or a can of compressed air to clear dust and debris from the hole. It should appear straight and clean. Finish the hole using an abrasive material like sandpaper to remove any imperfections, splinters, or burrs. 

Drilling Into Different Material

Not all material is created the same. How you drill into concrete is a lot different than wood, for example. Lets walk through common materials, and what you need to pay attention to when drilling pilot holes into them.

Concrete

Drilling a pilot hole is especially important when working with concrete. For one thing, it’s a good way to find rebar. While you can drill through rebar using appropriate tools, it may be easier to find another drill site. 

Concrete in particular requires a pilot hole slightly longer than the fastener you are inserting. A short basin at the bottom of the hole ensures that the debris from concrete aggregate will have somewhere to go, and your fastener will fully penetrate the concrete. 

You’ll also probably want to use a high quality hammer drill for concrete.

Drywall

Whether sheetrock or drywall, this porous, fragile material requires special attention.

The goal of drilling into drywall is usually to hang something on the wall using an anchor. For items weighing less than 10 pounds, a pilot hole is necessary to insert a plastic sleeve anchor. Between 10 and 25 pounds, a self-drilling threaded anchor can be used without a pilot hole. 

For hanging items that are more than 25 pounds, but less than 50, molly bolts, toggle bolts, or snaptoggles can be used. If you’ve purchased a dull-tipped, unpointed bolt, a pilot hole is mandatory.

Sharp-tipped, pointed anchors can be inserted directly into the wall using a hammer — no drilling or pilot holes required. For any item larger than 50 pounds, find a stud and drill your pilot hole into that. 

Wood

Dangers of screwing into wood include damage like splitting and cracking. The best way to reduce the risk of splitting wood is to drill a pilot hole. 

Fastening two pieces of hardwood together without a pilot hole is effectively impossible. Softwood is more forgiving, but a pilot hole is still recommended. 

You can use a standard corded drill or cordless option for wood, as you typically don’t need a tremendous amount of power.

MDF

Medium-density fiberboard is a construction product made from reconstructed wood fibers. Pilot holes are necessary when screwing into MDF. 

Tile and Glass

Low and slow is the name of the game when drilling into tile and glass. A piece of cardboard taped over the surface of the material may help the bit enter more smoothly. To make large holes in glass without breaking it, a pilot or starter hole is recommended. Use successively larger bits to enlarge the hole to the desired size. 

Conclusion

Pilot holes are an essential part of construction. The bit and technique used to drill a pilot hole depends on the material you’re working with. Observe safety protocols and the recommendations in this article to drill perfect pilot holes every time.