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How to Create a Large Perfect Hole

Anyone can drill a nice one-half-inch-diameter hole with a drill and drill bit. But what do you do when you need a larger hole? Sure, you can use a flat or twisted spade bit, but I’m talking about a BIG hole. How about one 4 inches in diameter?

Yes, you can grab your jigsaw or rotosaw, drill and 3/8-inch bit to make a pilot hole, but I doubt you’ll end up with a perfect circle. If you want a perfect circle, you probably should consider using a hole saw. They come in a wide variety of sizes and with some practice, you can create perfect circles each time you use one.

Watch a video of a hole saw in use here if you don’t believe me:

http://go.askthebuilder.com/holesaw

Degree of Difficulty: hammer-2-5

Step One: Take time to familiarize yourself with the different hole saws. Not all are the same. Some kits allow you to interchange the hole saw while the pilot bit stays in place in the drill. The quick interchange feature of some hole saws saves time.

Step Two: Be sure you’re aware of the effective cutting depth of the hole saw. If you need to create a perfect circular cut in a thick material, use the correct hole saw that allows you to go the distance! 

Step Three: If cutting wood with a hole saw, be sure you match the drill to the task at hand. If you’re trying to drill a 4-inch-diameter hole in oak or southern yellow pine, you’ll need a powerful drill. The hole saw will create lots of drag that could burn up a cheap or inexpensive drill.

Step Four: Multi-speed drills that have a high-torque lower-speed setting are ideal to pair up with hole saws. This low speed setting allows the hole saw to slowly chew through the material you’re cutting and gives you excellent control at the same time.

Step Five: Inspect the backside of the object your drilling through. You don’t want your hole saw to cut into a wire, cable, water line, PVC drain line, cable TV cable, etc.

Step Six: If drilling a large hole in a floor joist or wall stud, be aware of your local building code requirements with respect to the hole location and its maximum allowable diameter. Stop by your building department and ask for a copy of the pages of the building code that deal with hole sizes in structural members.

Step Seven: Before using the hole saw for the first time, do two things. Test drill a few holes using the smallest hole saw in the set. Drill into and through some scrap material. Get a feel for how the drill works and what kind of pressure you must apply to get a clean cut.

Step Eight: Moderate and even pressure almost always delivers the best results when using a hole saw. Be sure the drill is perpendicular to the material being cut so the hole is not slanted. Wear goggles, not safety glasses, if drilling above your head.

Summary:  Hole saws have been around for years. Keep in mind the more expensive ones are probably made with better materials that will stay sharper for a longer time.

Column HT009

Click on this link to search for hole saws

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One Response to How to Create a Large Perfect Hole

  1. I have a set of hole saws. My dad showed me how to make a perfect hole for a door knob. He said drill through the first side of the door and when the center drill bit just barly pokes through the other side stop and change sides. then put the drill bit into the hole it made from the other side. then drill the rest of the hole. If you do it this way you will not splinter the wood on the outside like drill bits often do.

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