To prevent dulling and binding when drilling holes with a hole saw:
- Use the hole saw to drill 1/8” deep into the surface.
- Remove the hole saw, and drill a series of 1/4″ diameter holes around the outside of the hole saw hole.
- Drill the rest of the way through using the hole saw, making sure to clamp a piece of scrap wood on the bottom of the work to prevent splintering.
The smaller diameter holes around the perimeter allow the sawdust from the hole saw to clear and prevent the hole saw from overheating.
Watch this video to find out more.
Danny Lipford: The hole saw is the perfect tool for drilling those large diameter holes, like this doorknob hole.
Joe Truini: That’s right, Danny. The problem with most hole saws, though, is that they dull really quickly. Here’s a great way to cut holes much quicker and cleaner.
Danny Lipford: Now this is a good one, you need to watch this.
Joe Truini: The first step is to use the hole saw to cut just about an eighth-inch deep or so. Then switch to a drill with a quarter-inch diameter bit, and drill around the perimeter of the hole. These holes create spaces for clearing out the wood chips, which keeps the hole saw cooler and cutting faster. Then switch to the hole saw, and finish drilling through the rest of the door.
Another benefit of the relief holes is that they help prevent binding, which can really twist your wrist.
Danny Lipford: Now this could be really helpful if you’re drilling in a hardwood door, or a plastic laminate countertop that may have two layers of particleboard.
Joe Truini: That’s right. And don’t forget whenever you’re using a hole saw to always clamp a piece of scrap wood underneath to prevent splintering on the backside.
Another useful remedy to prevent binding of the hole saw blade and a nasty twist of the wrist is to slightly rock or tip the drill from side to side (or) in some semblance of a circle so that the bit is bearing on essentially one point as you go thru as opposed to everywhere in the circle. You’ll get a feel for how much to rock it – and don’t get too confident and stop rocking just because it’s working so well because it’ll grab again and give you the nasty twist.