1870 Cylinder-Operated Flushbolt

Description: Designed for greater key control, the 1870 Cylinder-Operated Flushbolt for aluminum stile doors prevents accidental locking of the inactive leaf of paired doors.

Function: Designed for use instead of conventional flip-lever operated flushbolts, the 1870 Cylinder-Operated Flushbolt gives building management key control of the inactive leaf of paired doors. Prevents casual locking of the inactive leaf by children or other 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 MS1850S Deadlock in active door for greatest security. May be installed to lock at threshold or at header.

Operation: 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. Accepts any standard 1-5/32” mortise cylinder from either or both sides. Cylinder must have MS® dimensioned cam.


Cylinder Backset: 31/32” or 1-1/8” only

Cylinder Height: Standard length (cylinder center to retracted bolt tip) is 12” with ± 1-1/4” adjustment. Other lengths available by special order.

Case: Measures 1” x 6” x depth.  Depth varies by backset (see table on catalog page). Steel with corrosion-resistant plating.

Bolt: Hexagonal 3/8” flat to flat, with 11/16” throw. Made of stainless steel.

Strike: 1/2” diameter hole in metal threshold or header is suitable. For wood thresholds, 4005 strike is available separately.

Faceplate: Measures 1" x 6-7/8".

Cylinder Cam: Operable by any standard mortise cylinder with MS® cam, dimensioned as shown. Cylinders with MS® cams can be readily obtained from most cylinder manufacturers. See CYLINDERS for cylinder make, thumbturn and trim ring information.

Standard Package: Basic lock mechanism boxed with actuator arm attached, rod/bolt assembly unattached. Stainless steel bolt guide, mounting screws, and installation instructions included. Cylinders available separately. Shipping weight: 1-1/4 lbs.


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

Accessories Cylinders Special Order Options

Lock mounting accessories and options.


Operable by any standard mortise cylinder with MS® cam, dimensioned as shown. Please see CYLINDERS for more cylinder, thumbturn and trim ring information. Other cylinder lengths available as special order.