I am trying to reinforce a custom door I am building. Because it's made only of two layers of MDF, it is not as rigid as I want it to be and shows signs of bowing. Since it's going to be a soundproof door, any curvature in the door will be detrimental to a tight seal around the stop.

The only low-profile solution to reinforcing the door that I have found is a 1/8"x1 1/2"x6' length of steel that I found at Menard's. It is very ridgid and would be perfect for attaching along the inside edge of my door which is also 1 1/2" thick. The problem is that I need to drill a 1"-diameter hole through it for the latch assembly, but I have no idea how I am going to do that with the cordless power drills that I have.

  • Note that when drilling steel, lubrication is important to keep the bit from overheating and destroying itself.
    – keshlam
    Dec 10, 2023 at 15:05

3 Answers 3


Using a holesaw in steel that's more than about 1/16" thick can be frustrating. The bits wear out fast, and it really likes to bind. I've had better luck using a step drill bit, like this one from Harbor Freight.

  • Yep, the 11 stepper looks perfect. Its amazing how clean a step drill makes holes. They work nicely in very thin sheet metal, also.
    – HerrBag
    Mar 21, 2013 at 12:34
  • So would this work well with a cordless power drill? I have a really nice Makita (don't recall the model offhand) and am hoping I don't have to buy a special drill. Mar 21, 2013 at 13:06
  • Yes, I use my Ryobi cordless for it, though I do use the lower gearbox speed. I've drilled up to 1/4" plate, (though you have to drill from both sides for something that thick, since each "step" on the bit is only about 3/16" thick."
    – Bob
    Mar 21, 2013 at 13:35
  • They also don't grab and wrench so severly as hole saws can.
    – HerrBag
    Mar 21, 2013 at 17:22

Step One

Drill a small pilot hole using a small diameter (1/8") Twist drill bit.

Step Two

Drill the 1" hole using a Hole Saw bit.


From your description it sounds like you intend to install this piece of strap iron along the latch edge of the door. Drilling a 1" hole through the strap iron for the door latch pin assembly is going to be the least of your problems. Any decent latch assembly has an additional rectangular face plate that gets recessed into the edge of the door edge as well. This would seem to demand a rectangular hole in your strap iron as opposed to round hole. (I can see a round hole as a possibility if you are using one of the cheap piece of junk door latches that has no screw-in face plate but I would normally tend to steer away from those).

A rectangular hole can be cut by drilling some smaller round holes and then using a saber saw with a metal cutting blade to open up the area to near full size and then following up with a mill file to shape to final size and fit.

A round hole can be cut in soft steel using a hole saw specifically designed for cutting steel. Optionally you could take the strap iron piece to a machine shop where they have a mill or proper drill press to prepare the hole for you.

  • The Schlage door handle I bought comes with the rectangular and round piece. The round piece is pounded in to where it's pretty snug, but I agree that the rectangular plate that you screw in is best. Mar 21, 2013 at 0:55
  • 2
    @oscilatingcretin - The round pound in piece is designed to be forced into a wood material, not into a steel strap. There is a good possibility that having the strap keeping the round part from seating fully to the wood surface will make it so that it is unable to achieve a good snug fit. (This would be particularly true if the round part has a slight taper to it).
    – Michael Karas
    Mar 21, 2013 at 13:10

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