BEST 9K37S Grade 1 Communicating Lever Lock

The BEST 9K37S is a Grade 1 communicating cylindrical lever lock from BEST's 9K Series heavy duty platform -double-keyed with independent control of each lever, 7-pin SFIC housing, UL listed for 3-hour fire doors, and built to the same standard that makes the 9K Series one of the most widely specified Grade 1 cylindrical locks in North American institutional construction. American Locksets stock the 9K37S. Free shipping on orders over $300. Call 877-471-4870 for core, rose, and finish questions.

What a Communicating Lock Is and Why You Need One

A communicating lever lock has a key cylinder on both sides of the door. But it's not a standard double-cylinder deadbolt, and understanding the difference matters for both specification accuracy and code compliance.

In a standard double-cylinder lock, one key controls both sides from outside, and the inside must be unlocked before anyone can exit. That design is hazardous in many applications and prohibited by Life Safety Code in rooms without a secondary exit.

The communicating function works differently. Turning the key in the outside lever locks or unlocks the outside lever only. Turning the key in the inside lever locks or unlocks the inside lever only. Each side is controlled independently by its own cylinder and its own key. When both levers are locked, the latch can only be operated by key from either side -both levers are rigid without a key. When either lever is unlocked by its cylinder, that side operates normally.

This independent control architecture is the correct specification for connecting rooms in hotels and motels, hospital suite doors connecting patient rooms to shared areas, office suite connecting doors between adjacent tenants, and any opening where two separate parties need independent access control from their respective sides. Do not install the 9K37S on any room with no secondary entrance -Life Safety Code and building codes govern this application. Confirm compliance with the authority having jurisdiction before specifying.

BEST 9K Series: What Makes It Heavy Duty Grade 1

The 9K isn't just ANSI Grade 1 certified -it's built for failure modes that standard Grade 1 locks can't handle. The rose locking pin prevents twisting, bending, or breaking under torsion attack. The slotted key release cam and locking lug assembly are designed so that even if the outside trim is damaged during a forced entry attempt, key access still functions and the inside lever remains fully operational. The outside lever sleeve is a seamless one-piece hardened steel alloy construction -no seam at the locking lug area where prying attacks focus. Hub-mounted torsion spring and strong retractor springs keep the lever from sagging under years of high-cycle commercial use. Zinc hubs with a shrouded locking lug add torque resistance at the point where leverage attacks concentrate.

Through-bolt mounting is standard on the 9K37S -two 5/16-inch holes at the 12 o'clock and 6 o'clock positions in addition to the standard ANSI A115.2 door prep. That through-bolting anchors the rose assembly across the full door thickness rather than relying on surface screws alone.

Specifications

Model: BEST 9K37S

Series: 9K Heavy Duty Grade 1 Cylindrical Lever Lock

Function: Communicating (S) -key in either lever locks or unlocks its own lever independently. Both levers are rigid when locked.

Cylinder Housing: 7-pin SFIC -accepts all BEST interchangeable cores. Ships less core.

Backset: 2-3/4" standard. Also available in 3-3/4" and 5".

Chassis: 2-1/16" diameter to fit 2-1/8" door hole. Critical components are brass or corrosion-treated steel. Conforms to ANSI A115.2.

Latch: Solid brass, 9/16" throw. Front 2-1/4" x 1-1/8" beveled.

Door Thickness: 1-3/4" to 2-1/4" standard. Spacers available for 1-3/8" doors.

Strike: S3, conforms to ANSI A115.2 for 1-3/4" doors. 4-7/8" x 1-1/4" curved lip.

Mounting: Standard ANSI A115.2 prep plus two additional 5/16" holes for through-bolts at 12 o'clock and 6 o'clock positions.

Rose Options: C (3" convex), D (3-1/2" convex), K (3" convex, no ring), L (3-1/2" convex, no ring)

Lever: High-quality zinc alloy, ~5/8" body diameter, ~4-3/4" handle length

Projection: Approximately 2-3/4" when mounted on 1-3/4" door.

Options: Lost Motion feature (45° lever rotation without engaging retractor). UltraShield antimicrobial finish (626AM). CORMAX key system.

Certifications: BHMA A156.2 Series 4000 Grade 1. UL listed 3-hour A label, single or double swinging doors. ADA compliant per ANSI A117.1 section 404.2.6. Florida Building Code listed. California State Fire Marshal listed. California Title 24 compliant (levers 14 and 15).

The Full 9K Series for Complete Door Schedules

If the communicating function isn't right for every opening, the 9K platform covers every standard institutional function: entrance (AB), classroom (A), office (B), storeroom (D), dormitory/bedroom (T), hospital privacy (H), and more -all using the same chassis, mounting prep, and SFIC core format. One key system, consistent lever style and finish, throughout the entire building.

American Locksets has stocked BEST 9K Series hardware since 2001.