How to Drill Door Lockset Holes
DEAR TIM: I've got to install a new interior door lockset. The door has no holes in it. I'm completely perplexed at how to drill the holes. Do I just grab my jigsaw? There must be secret tricks and tools you use to accomplish this. It seems much too hard for me to do. Should I just hire a professional to do this? I'm on a razor-thin budget and would prefer to do this myself. Oh, I'll have to do this in the future with other doors, so that's why I'd rather discover how to do this. Teresa D., Danbury, CT
DEAR TERESA: Oh, I can sure understand your bewilderment if you've never seen this task performed by a carpenter. The short answer to your question about tools is easy. You don't need special tools to drill the two holes required for the lockset. But it helps if you have a handy jig that is quite specialized. This jig didn't exist years ago when I had to create perfect lockset holes.
The last thing you want to use is a jigsaw. You need two different hole saws to create the perfectly round holes in the face of the door and the smaller hole in the edge of the door. The hole diameters are 2 and 1/8-inch and 1-inch respectively.
Hole saws have been around since dinosaurs roamed the land. In all honesty, hole saws are old tools used by carpenters for generations. In it's most basic form, think of an empty soup can. Cut teeth on the open can edge and then somehow attach it to a drill. That's what a crude hole saw looks like.
If the metal of the hole saw is thick enough and you can position it at a 90-degree angle to the piece of wood you're drilling - and keep it at 90 degrees while drilling, you'll end up with a clean perfect hole in the door. But it's quite challenging to keep the hole saw at a 90-degree angle.
If you want your door lockset to operate smoothly and not bind up when you turn the doorknob or try to lock it, it's imperative the two holes you drill align perfectly in both directions. The centerline of the holes must be at the same height and they must be drilled at the precise 90-degree angle to the face of the material being drilled.
In the old days, I'd take an accurate small square, measure up 36 inches from the bottom of the door and use a sharp pencil to make a fine line on the face of one side of the door where the lockset handle will be. I'd use the square on the edge of the door to make sure the line was at a 90-degree angle with the edge of the door.
I'd then use the square and sharp pencil to extend this line around the edge of the door and to the opposite face of the door. After drawing the line on the opposite face of the door I'd check with my tape measure to ensure the line is the same distance up from the bottom of the door. If the door is new and has never been trimmed, the bottom of the door should be square with the faces of the door.
The larger 2 and 1/8 inch hole is drilled first. Hole saws come with a centered pilot bit that allows you to center the hole saw. Without this pilot bit, the hole saw would wander across the face of the door as you start to drill the giant hole.
To know where to drill this hole from the edge of the door, you need to know the backset of the lockset. The backset is the distance from the edge of the door to the center of the giant hole you drill in the face of the door.
Most interior locksets have a 2 and 3/8-inch backset. Exterior locksets commonly have a 2 and 3/4-inch backset. I disliked interior locksets with the smaller backset as my knuckles always hit the door jamb. Be aware you might be able to find interior locksets that offer the longer backset dimension.
You can get in trouble fast if you measure the same backset dimension from the edge of the door. Most doors have a very slight bevel cut that allows the door to not strike the door jamb as it closes. You can see this bevel if you put your square on the face of the hinge side of the door. The hinge side is the side of the door where you see the hinge pins once the door is closed.
The bevel cut can be as much as 1/8 inch! This means on the non-hinge side you'd measure 1/8 inch less so the centerline is the same on both sides of the door and the hole saw pilot bit holes line up. See how easy it is to make a mistake?
With the hole centerline marked out, it's time to drill. Don't just drill from one side. You want to drill part way into one side of the door, stop and then start to drill from the other side. This ensures you don't splinter the wood on the face of the door as you blast through drilling from just one side.
With the large hole cut, it's now time to drill the small 1-inch hole in the edge of the door. You want to keep the drill level and square. This is very difficult to do.
Have I convinced you to invest in the new door lockset jig tool that does all the magic centering for you? This tool keeps the hole saws square and centered for you. All you have to do is draw the accurate pencil lines so you can align the hole jig.
The best part is the jig will pay for itself before you finish drilling your first hole. A professional finish carpenter wouldn't even come to your home to start the job for what the jig will cost you. I'm confident you'll have great success!