Although you can use metal drill bits for wood if you’re in a pinch, we don’t recommend it. Metal drill bits are typically made from harder materials designed to cut through metal. While this can make them effective at drilling through wood, it can also cause them to splinter or tear the wood if not used carefully.
Also, metal drill bits do not have the same flute design as wood drill bits, making them less effective at removing wood chips and sawdust from the hole as you drill. This can cause the bit to overheat and dull more quickly, which can also cause the wood to splinter.
If you need to drill through wood, it’s generally best to use a wood drill bit specifically designed for the task. These bits are typically made from softer materials and have a wider flute design that is better suited for removing wood chips and sawdust as you drill.
Metal Drill Bits vs Wood Drill Bits
If you use a wood drill bit on metal, you may end up destroying the bit. Unless you use it for drilling soft and thin metals, your drill bit won’t work. A metal drill bit if used on wood can damage the wood. An exception for metal drill bits is if the diameter is small. In such a case, you will find little difference between metal and wood drill bits.
How to Distinguish a Metal Drill Bit from a Wood Drill Bit
It is crucial to tell the difference between a wood drill bit and a metal drill bit to get the best results. Fortunately, there are a few clear distinguishing features that set one apart from the other.
Wood Drill Bits
A wood drill bit has a “spur” (also called “brad” – see below) and a lip. If you are looking at a spade bit, these components are well-defined. You can easily identify the drill bit as it has a unique shape. We use spade bits to create oversized holes, that exceed the maximum diameter of the drill bit that you can fit into the chuck of a power drill.
You may also come across wood drill bits that resemble metal drill bits. In such a case, the difference is more subtle – the material used will be softer, and the bit may be differently colored or marked. Typically, wood bits come in black and silver, but you may find other colors as well.
Metal Drill Bits
A metal drill has a cylindrical structure that has fluted ridges along its edges and a beveled tip. The cutting edge of a metal bit is extremely critical and needs to be touched up from time to time. Metal tips typically come in black, golden (frequently coated with titanium dioxide finish) and copper color.
Although metal drill bits are normally hardened to a high degree, the titanium dioxide and other coatings protect the surface from chipping and overheating. Because of the structure and hardness of a drill bit, you can use it to drill into harder material.
Best Practices for Drilling Holes in Wood
Sometimes, drilling a simple hole into wood can be more challenging than you expect. Here are a few useful tips to make your drilling jobs easier:
Use a Punch
When you start drilling a hole, the bit tends to wander, because of the way it spins. Use an awl, punch, or a sharp nail to punch an impression at the drill location. It will prevent your drill bit from “wandering” when you first apply the drill bit to the surface of the wood. Your holes will be more accurately placed.
Make a Pilot Hole
Regardless of the size of the final hole you require, start the drilling process by drilling a pilot hole with a thin drill bit. The result is that you have to use less force and there is less chance of your drill bit shifting the hole.
Drilling directly with a thicker drill immediately can cause the center of the hole to shift and cause problems in fitment.
Don’t Use Excessive Force
Like a saw, you need only to apply constant pressure to the wood but not excessive force. You may break a thin bit by overly forcing it. If you find the drill bit resists too much, you may need to change the drill bit or sharpen it.
Clear the Swarf
The design of a drill bit is to cut into the material and remove the waste material called “swarf” through the flutes. Sometimes, especially with soft material, the flutes of the drill bit get clogged with swarf causing the bit to resist. While moving the bit up and down in the drill hole usually clears the swarf, you may have to remove it manually.
Make Staggered Holes
Drilling too big a hole too quickly can make drilling more difficult. Gradually increase the diameter of the drill bits until you reach your required diameter. It makes the entire process easier and prevents the wood from tearing or splintering, creating a cleaner hole.
Avoid Splintering by Using Tape
The cutting action of a drill bit can cause the wood grain to tear and spoil the appearance of the wood, known as “tear out.” It is particularly noticeable with softwoods like pine. For a cleaner hole, place a piece of painter’s tape on the wood. Now, if you mark the hole and drill it through the tape, you can prevent tear out.
Select a Suitable Speed
Unlike drilling harder materials like metal, you need to use higher speeds for drilling wood. If the drill bit spins too slowly, it may “plow” through the wood, damaging the surrounding area. With higher speeds, the flutes of the drill bits, grab the material and break it off in micro-bits, which come away more readily.
Drill Size vs Fastener Size
When you are drilling a hole for a screw or a nail, the inner diameter of the hole needs to be slightly less than the outer diameter of the fastener.
Control Hole Depth with Tape
We frequently need to drill holes of a particular depth. The reason for this is usually that we don’t want a through-hole. You can mark off the part of the drill bit that you don’t want to penetrate with painter’s tape, leaving the rest of the length exposed. While drilling, drill only as far as the limit is demarcated by the tape.
Hogging a Hole
Sometimes, you may not have the final drill bit size required for driving a screw. In such a situation, after drilling the hole, you can move the drill bit up and down, pressing on the sides of the hole. It should enlarge the hole slightly, creating enough room for driving in the screw. Take care not to overdo it or you might break your drill bit.
Conclusion
As a woodworker, your primary weapon is your skill, and it gets better over time. But you also require suitable equipment to get your job done. Knowing the best way of using equipment and accessories will keep you on top of things all the time.
Drill bits are some of the handiest accessories in your woodworking shop. If you know how to distinguish the different types and how to use them, you can get the best out of your drill bits.
Although you can use metal drill bits for wood, save that for an emergency. The best approach is to know the difference between wood drill bits and metal drill bits and keep sufficient stock of wood drill bits to use in your woodworking projects.
