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Can I rebore a 2 1/2" backset to a standard backset?

user-514039's picture

I have a house full of doors with 2 1/2' inch backsets and didn't realize it until I had filled, primed and painted all of them.  Of course, I hadn't saved any of the original doorknobs I took out.  Can I rebore the holes to fit a 2 3/8" backset?  I'm afraid it will make the hole too big.

Quite a few, if not most, (post #207082, reply #1 of 4)

Quite a few, if not most, strikes/latches are universal for either 2 3/4" or 2 3/8" backsets these days. 2 1/2" would be unusual but the rosette may cover the difference if that's what you have.

See the specs on this Schlage for example.

Beat it to fit / Paint it to match

Schlage apparently has some (post #207082, reply #2 of 4)

Schlage apparently has some styles that are more or less fully adjustable (requires some extra parts apparently).  However, they are mostly commercial designs.

You might see if you can get replacement latches in the length you need, to fit the brand of knob you want.

But I'd first see if the style knob you've picked will cover the 1/8" offset.  If not, picking a style with a slightly larger flange may be all that's needed (aside from notching out the bore a bit).

Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

I'll bet the original guy who (post #207082, reply #3 of 4)

I'll bet the original guy who bored the holes simply drilled them 2-1/2 using 2-3/8" hardware....1/8" isn't much and most hardware will cover that.   Depends on your hardware.   If the holes are 2-1/4" and (like some I'm working with this week) the plates on the knobs are only an eigth inch larger then you'd have a hard time.

Having said that, there's nothing wrong with morticing the bolt plate deeper than usual and adding a thin spacer such as another plate so the actual plate is flush with the door if it looks and functions correctly.   Different mechanisms handle misalignment better or worse so it depends on what knobs you're going to use for replacements.

Good luck

If I could edit my location it would say I'm now in Reno :-)

Thanks, everyone, for the (post #207082, reply #4 of 4)

Thanks, everyone, for the advice.  I found a jig and am going to rebore the holes to 2 3/8.  I did talk to a locksmith who said that manufacturers stopped making the 2 1/2 backset knobs about 20 years ago.