1877 Cylinder-Operated Flushbolt

Designed for greater key control, the 1877 Cylinder-Operated Flushbolt prevents accidental locking of the inactive leaf of paired wood doors. May be installed to lock at threshold or at header.


Designed for use instead of conventional flip-lever operated flushbolts, 1877 Cylinder-Operated Flushbolts give building management key control of the inactive leaf of paired wood doors. Prevents casual locking of the inactive leaf by unauthorized persons. Uses same basic over-center action mechanism as MS® pivoted bolt deadlocks. Recommended for installation at both top and bottom of inactive door with MS1837 MS Two-Point Deadlock in active door for greatest security. May be installed to lock at threshold or at header.


360° turn of key throws or retracts the hex-section bolt. Key can be removed only when bolt is in a positively locked or unlocked position. Lock accepts any standard1" [25.4 mm] length, 1-5/32" [29.4 mm] diameter mortise cylinder with MS® cam such as the 4036 Mortise Cylinder or thumbturn such as the 4066Thumbturn, available separately. Lock accepts cylinder from either or both sides.


Cylinder Backset: 1-1/4" [31.8 mm] only.

Cylinder Height: Standard length (cylinder center to door end) is 13-1/2" [342.9 mm]. Please contact factoryfor other lengths available by special order.

Case: Steel with corrosion-resistant plating. Measures 1" x 6" x 1-29/32" [25.4 mm x 152.4 mm x 48.4 mm].

Bolt: Stainless steel. Hexagonal 3/8" [9.5 mm]flat to flat, with 11/16" [17.5 mm] throw.

Strike: 2-1/4" x 15/16" [57.2 mm x 23.8 mm] strike is supplied.

Armored Faceplate: Measures 1-1/4" x 15-5/8" [31.8 mm x 396.9 mm]. Available in choice of 313 Dark bronze anodized, 628 Clear anodized, US3 (605) Bright brass, US26D (626) Satin chrome.

Standard Package: Flushlock mechanism boxed with actuator arm attached, rod/bolt assembly unattached. Stainless steel bolt guide, mounting screws, and installation instructions included. Cylinder available separately.

Shipping Weight: 2 lbs [0.91 kg]


Related Products: When purchasing this product, please consider the following related products, available separately:

Cylinders Special Order Options
Standard 1" length, 1-5/32” diameter mortise cylinder with MS® cam such as 4036 Mortise Cylinder, 4066 Thumbturn Other cylinder height / length available by special order. Please contact factory.