My current door knob hole is not standard. The backset it uses is 3 3/4 inch which I no longer have. I want to re-drill a hole so that I can use a standard 2 3/4 inch backset. But how do I do that? Do I fill in the existing hole with some type of wood plug...then re-drill a new hole?

  • So "standard" is now 2-3/4 inch backset, but 3-3/4 inch is available. – Jim Stewart Nov 3 '17 at 11:26
  • Locksets from Schlage, for example, have an adjustable bolt length. I don't think it goes all the way to 3-3/4", though. That might call for a specialty set. – isherwood Nov 3 '17 at 15:35

Your choices with regard to this depend greatly upon the materials, construction and finish of the existing door.

  1. If it is a solid wood door that will end up with a painted finish then it is possible to clean up the existing hole and make a surface to surface plug of wood that is glued into place before starting the drilling for the new 2 3/4 inch backset.
  2. If it is a door that has a wood laminate inner and outer surface but a particle board core it can be possible to perform similar steps as outlined above for solid wood doors. Truing up a particle board inner core can be harder to get good glue surface, particularly if the original hole was cut with a coarse toothed hole saw that chewed up the inner surface of the hole.
  3. For plastic or steel clad doors the most likely thing you are looking at is to replace the whole door with a new one. I have seen some types of tricks used for doors of this type that add brass plates to both sides of the door that are secured to the existing door surface. The added plates are used to support the new cutout and bridge over the old one.
  • Thanks for the reply Michael. Yes, the door is solid. Guessing any old solid wood piece would do? Can you recommend a wood glue? Somewhat handy around the house so I am excited about giving this a go. – Gary Nov 3 '17 at 14:13
  • Don't use "any old" wood. It should be hardwood or engineered (plywood) for stability. Pine and particle board aren't ideal. Any wood glue (enhanced white glue) or urethane should do. – isherwood Nov 3 '17 at 15:36
  • Pro grade 2-part wood filler (like auto body filler) works really well for patching doorknob holes. It is easily planed and sanded smooth; drills well too, especially when you need to drill nearby and will hit part of the patched area (like when going from 2 3/8" backset to 2 3/4" backset). I have used it for this several times. – Jimmy Fix-it Nov 3 '17 at 16:00

Another option to quickly cover an existing hole are wrap around plates for the door:

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Door guard

These are sold as a way to reinforce the door, cover cracked wood from a break in, or to cover existing or misplaced holes. They come in a variety of sizes and make covering holes quick and easy. For something as large as a lockset hole, I'd probably still fill the hole with something, but since the plate will cover the repair, you can do a much quicker, rougher fix. You could even leave the hole open and just cover with the plate for a super quick fix.

  • I'm kind of a perfectionist or try to be. At first glace you can't really tell anything was done but if you look closely. I give it 8 out of 10. Wife was happy so that is all that matters. Thanks for the help everyone. – Gary Nov 6 '17 at 4:13

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