Q&A / 

How to Drill Holes

DEAR TIM: Last week you helped Sally use a circular saw. I’ve watched people use a simple electric drill for years but never held one in my hand. Can you teach me how to use a drill, how to drill different sized holes and share any tips about what you’ve discovered over the years about drilling into wood, tile, metal and concrete? Alie W., Morgan Hill, CA

DEAR ALIE: I must tell you that your question caused me to do a hard reset in my brain. All too often I forget what it was like to be young and not have one speck of experience doing anything. Currently I’m where you are with respect to Morse code and other aspects of my amateur radio hobby. I’m groping attempting to do things in radio I’ve never done before and constantly am asking for tips from more experienced radio operators. It’s easy to forget what it’s like for a beginner.

As simple as you might think an electric drill is, a new modern drill can be a somewhat complicated tool. I remember my first electric drill. It was single speed and had an on and off switch. It was one speed - fast!

These tools and bits allow you to drill holes through a multitude of things. Photo Credit: Tim Carter

These tools and bits allow you to drill holes through a multitude of things. Photo Credit: Tim Carter

Modern electric drills have forward and reverse, they’re variable speed, some have hammer action built in that allows you to drill and chisel through masonry at the same time, some have clutches that stop or slow the drill when a certain amount of resistance is encountered, etc. In other words, a modern electric drill that sports all these features is a complex tool!

But don’t allow that to discourage you. You don’t have to master all of those features on the first day you practice with one.

If you’re going to purchase a new drill, realize the newer cordless drills may be what you want. If you only plan to use the drill sparingly and not for hours at a time, then a cordless drill is perfect. If you plan to drill for hours and hours on end, I’d get a corded drill that operates on standard 120 volts provided by the electric outlets in your home.

Let’s talk about the accessories available to you to drill through just about any material. There are so many, it’s impossible for me to list them all so I’ll just give you the very high-altitude overview.

Wood might be the most common material you drill through. There are regular twisted bits that do a splendid job of drilling small holes up to one-half inch into and through wood. Some have tiny sharp centering tips at the top of the bit. These spike tips prevent the drill bit from wandering as you start the drill spinning. Wandering bits is a common problem drilling just about anything, especially metal, tile or any material that’s very hard.

If you want to drill larger diameter holes in wood, you may want to use a spade bit or even a hole saw. These accessories are designed to drill perfect round holes in materials. As you might expect, there are all different types of spade bits and hole saws, so look at many and read the claims the manufacturers make about them.

My guess is at some point you’ll need to drill into or through concrete, brick, stone or thick tile. You’ll need a special bit that has a carbide tip on it. Carbide is very hard, only a few materials - like diamond - are harder than carbide.

Bits equipped with this tip grind their way through natural stone, concrete and tile. These bits bore even faster if the drill is a hammer drill. Hammer drills rapidly pulsate up and down as they turn. The drill becomes a miniature jack hammer much like workers use to break apart concrete slabs.

If you’re drilling steel or iron, you’ll want special drill bits made for metal. On the label of the bit, it will clearly say it’s made to drill into metal and list the metal types. These hardened bits, when mixed with oil and slow drilling speeds cut through metal very quickly. The key to drilling through metal is to keep the drill bit cool. Oil does this by absorbing lots of the heat created by the friction of the spinning drill bit in the metal.

Here are a few tips I’ve discovered after drilling thousands and thousands of holes in my career:

  • Always wear eye protection whenever drilling holes
  • Use a drill press to create perfect holes in thick material
  • Use increasingly larger and larger bits when drilling a large hole in metal
  • To avoid blowouts when drilling cabinet knob holes, use a sharp bit and use minimal pushing pressure just as the bit breaks through the back of the door or drawer
  • Use a handy jig to create slanted pocket holes to join pieces of wood with screws instead of glue
  • When drilling a deep hole in masonry with a carbide bit, pull up on the drill every five seconds to help get concrete dust and particles out of the hole
  • Always practice on some scrap material when drilling through anything for the first time
  • Practice, practice and practice to become proficient

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