Okay, so I need to replace an old door knob for my mom.

I guess she had tried to do it and wound up losing all packaging and the installation instructions, so I have no template for how much larger the hole needs to be.

I have a drill attachment set and a cordless drill, but that's all (see pics). I've read about a bunch of fancy tools that are made specifically to do what I need done, but I can't afford to buy anything.

As for a template, I used fingernail polish on the part of the new knob that doesn't fit into the existing hole. I couldn't think of another way to get a somewhat accurate outline of the hole.

Also, I can't take the door off of the frame, it has to stay on the hinges.

I'm usually pretty good about figuring this sort of thing out, but I'm stumped. I can technically install the knob & it'll lock & work okay, but it ends up scraping against the wood and it comes loose very quickly.

About the only thing I can come up with is using the sander bits & going at it that way..

Any help is greatly appreciated!

Here's a pic of the tools I've got available and the makeshift 'template' for the size I need

Tools available Doorknob hole in door

  • A picture of the new knob would be really beneficial. Most new knobs usually start with a 2 1/8" hole in the face of the door 2 3/8" back from the edge. You may have that in your kit. One more thing to ask, do you have access to C clamps?
    – Jack
    Feb 21, 2018 at 1:49
  • 1
    scraping against the wood ... what is scraping? ....... comes loose very quickly ... what and how does it come loose?
    – jsotola
    Feb 21, 2018 at 1:53
  • I frankly would go buy another door knob that fits.
    – agentp
    Feb 21, 2018 at 2:48
  • is this a passage doorknob with no latch?
    – agentp
    Feb 21, 2018 at 12:34
  • This may be an XY problem. If the knob comes loose very quickly, making the hole bigger won't help. It could very well be the knob is incorrect for the door given the current holes. Post pictures of the new knob, and include a measurement of the existing hole.
    – mmathis
    Feb 21, 2018 at 14:41

2 Answers 2


With the paddle bits or the hole saw bits that you have drill a hole in a scrap piece of wood that is the correct size for the knob you are trying to install. It would be good if this scrap was at least 3/4" thick.

If you have clamps - clamp this scrap with the hole in it over the hole in the door and use it as a guide to then drill the correct size hole in the door.

You didn't hear this from me - If you don't have clamps you might be able to just hold the guide tight and drill carefully. Maybe a helper would be good.

You could also try the sanding drums - it doesn't have to be pretty since the knob will cover things up, but they look cheap and might wear out before you get to where you need to be.

You can do it. Go for it. Persist. Don't forget your safety glasses.

  • 1
    It should also be possible to temporarily screw the scrap to the door, placing the screwholes where they will later be covered by the doorknob. Feb 21, 2018 at 11:55
  • Yes, RedGrittyBrick, excellent idea.
    – paul
    Feb 21, 2018 at 12:19
  • 2
    Not only does the hole have to be the right size it HAS to be the correct distance from the side of door to match the the throw of the latch.
    – Alaska Man
    Feb 21, 2018 at 17:45
  • Thank you so much @paul! I pretty much just went with the sanding drums, and you're right, it was not pretty at all. And it took FOREVER. And it was still uneven. But I got it to work. I didn't have safety goggles, so I made a kind of super crappy welder's mask looking thing out of a clear plastic soda bottle and string. It kept the crap out of my eyes at least. My whole thing is improvisation and making due with what I have, so your answer was definitely helpful. Sorry that it took, uh, three months to respond! Jun 2, 2018 at 1:17

So I did it.

I had no C clamps, no scrap wood and no helper. I ended up using the sanding drums, which took a ridiculous amount of time, but it worked.

I appreciate all the attempts to help me out with this, even though my appreciation is coming three months after the fact.

It's so important to try to learn how to make due with what you have instead of running out to buy something that will work, but you don't really need. Ingenuity is part of what makes us human and we're losing that exceptional trait very quickly because we can just go out & buy something instead of trying to make it work.

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