I have a set of 1927 french doors that are 18" wide and have a built-in astragal -- measuring ~7/8" wide and ~1/4" deep -- on both doors. The astragal narrows to about a 1/4" where the locks used to be, allowing room for the former lock.
I'm restoring the doors and I'd like to add a lockset to the active door (passive door is secured with slide bolts). I'm wondering if I should try and add a modern mortise lock to the door by removing whatever filler is in the old hole or attempt to add a modern deadbolt and knob in.
My concerns with using a modern deadblot/knob is that the distance between the base plate and the strike plate will be too great and the knob's latch won't be long enough to securely catch.
Here's a picture of the door edges. The original strike plate is still there, but the hole where the mortise lock used to be has been filled.
How would you proceed?
As a side note, I've considered replacing the doors with a new set, but no one stocks french doors in this size. When installers come out, they all suggest adding a full size entry door, but a full size door would open too far into the room and be awkward in the space. Also, I just like the look of the smaller doors. The only other replacement option I've thought of would be to use a pair of 18" sidelights and turn them into french doors.