I've bought replacement door knobs that look like they need a small 1" bore, and screw directly onto the wood. Unfortunately my door has the larger 2" bores and the door knobs screw into each other.

I've looked around online and it seems like everyone wants to make their small bore bigger - I want to do the opposite. Is there any way to accomplish this or are the new replacement knobs I have useless unless you're drilling in a brand new piece of wood?

I just don't understand why this isn't all standardized.

  • 1
    Buy knobs to match the hole you have retrofitting will be difficult to make pretty
    – Kris
    Aug 7, 2019 at 0:53
  • Are you sure you need a 1" bore, and not the more common 1 1/4" or 1 1/2"? Cuz they make adapter plates for 1 1/4" and 1 1/2"... Aug 7, 2019 at 2:31
  • 3
    Possible duplicate of Door lock hole drilled too big
    – Solar Mike
    Aug 7, 2019 at 8:03
  • I think 1.25” would be fine, I just need wood to screw the door knob plate to. I didn’t know about adapter plates, I will look those up!
    – thedodus
    Aug 7, 2019 at 11:25
  • Doorknob bores have been standardized at 2-1/8" (for 2" hardware) with a 2-3/8" backset for a good 40 years. You've apparently purchased something intended for vintage or custom doors. In order to provide a good answer we'd need to know what sort of doors you have and what finish is on them.
    – isherwood
    Aug 7, 2019 at 18:24

2 Answers 2


I had a similar problem. I needed to go from a 2" hole to a 1" hole. I got a 2 1/4" hole saw and cut a hole through a piece of wood the same thickness as the door. I took the plug from the hole saw and glued it into the hole in the door. Sanded it, filled it in with a little wood putty and then drilled my 1" hole. Might be a little more work than you want to do but it did work.


They are standardized! Your door is the standard!

The doorknob is wrong. The people selling it to you should have had this conversation with you, and warned you that it probably won't fit your door. Take it back, let them learn their lesson.


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