I have a number of original interior passage knobs in my late 1940s house that would greatly benefit from tubular latch replacements. They have friction in them and often stick with the latch retracted into the door. No amount of cleaning or graphite seems to help.

I'm looking to purchase replacements, but am stuck on the first step: trying to determine what the backset is. Seems the usual sizes are 2 3/8" and 2 3/4", neither which seem close to the measurement from the front plate to the middle of the door knob hub. In reality, 2 17/32" seems to be the measurement.

Can anyone provide some clarity?

vintage tubular latch

  • The two sizes most common today are not gheonly two backsets that have been manufactured. A locksmith could order something for you that would fit (or might have it in stock if that size was common in your area).
    – keshlam
    Feb 14 '16 at 0:25
  • ... and for what it's worth, I'd call that 2.5"
    – keshlam
    Feb 14 '16 at 3:31
  • 3 ideas, none of them great: (1) install mortise locks -- those exist in 2.5" backset; (2) try a 2-3/8" drive-in (doesn't have the faceplate) and see if they still latch; (3) try a regular 2-3/8" and see if you can wiggle your knobs closer to the strike. Feb 14 '16 at 14:42

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