CCH Exclusive, Interior Bit Key Mortise Lock


Case: 3 ¾" tall x 3 ¼" deep x 9/16" thick
Face Plate*: 5 ½" tall x 15/16" wide
Backset: 2 ½"
Knob Hub to Keyhole Center**: 2 ¼"
Knob Hub: 5/16" diameter on the diamond

*Face plate is intentionally oversized to allow for replacement use on older doors which typically have worn edges around the original lock face.

**Measured as the distance from the center of the knob hub to the center of the round portion of the keyhole. This is the standard distance for our line of bit key escutcheons.

1 each: Solid, Cast Brass Mortise Lock
1 each: Solid Brass Strike
1 each: Solid Brass Bit Key
1 set: Solid Brass Screws

Sold Each

Please note: this lock is designed for interior use as a privacy measure. It is not intended for use as an exterior security lock on entry doors.

Made exclusively for Crown City Hardware in the USA. As the 31C and 31D series locks have largely replaced the 31A and 31B locks, this lock is not usually stocked and is now manufactured to order. As such they are non-returnable and non-refundable.
Item Number: 31A

Crown City Hardware premium grade, solid, cast brass bit key mortise lock. Our own exclusive, interior mortise lock, designed for both replacement of older locks and new installation. The lock was designed with special features making them ideal for restoration work:

  • The face size is slightly oversized. This means that minimal carpentry work is needed to make for a good, flush fit in old doors which often have worn wood around the original lock face.
  • The latch mechanism is double sprung, allowing for the removal of one spring to adjust the turning tension of the door knob. This is a great feature for older, more fragile glass knobs which often wear loose from their bases.
  • The entire lock is cast from solid brass, including the lock case (which has been painted black like the antique original), in small batches and finished by hand. The lock is manufactured and finished in the U.S., and has been designed for years of uninterrupted use in your home.

Please note: while we still love this lock and offer it for those that want a solid brass, black lock casing, we are now incredibly proud to offer our Signature Series 31C bit key mortise lock. It was built to our exacting specifications and is now available on our web store. It’s a higher quality lock, with additional features, at a lower price!
$128.49 to $162.59
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Availability: In Stock