Cal Royal NM8453 Heavy Duty Grade 1, Entrance Mortise Lockset

The Cal Royal NM8453 is a Grade 1 heavy-duty entrance mortise lockset from the NM Series. ANSI function F20: single cylinder with deadbolt. That's the critical specification that separates the NM8453 from the NM8050 (which is F04, entrance without deadbolt). The NM8453 includes both a latchbolt and a 1" throw deadbolt in the same lockcase — the deadbolt is projected by key from outside or thumbturn from inside, providing two-point security from a single door prep.

How the F20 Entrance Function Works

The latchbolt retracts from either side by lever unless the outside lever is locked by the toggle button. When the outside lever is locked, latchbolt retraction requires a key from outside or the inside lever. The outside lever is unlocked by the toggle button when the deadbolt is retracted.

The deadbolt projects by key from outside or thumbturn from inside. Both the deadbolt and latchbolt retract simultaneously when the inside lever is operated. The latchbolt deadlocks automatically when the outside lever is locked or when the deadbolt is projected. Inside lever is always free for immediate egress.

This two-bolt combination in a single mortise lockcase is why the NM8453 is specified for exterior entrance doors in offices, commercial buildings, schools, and light institutional applications where deadbolt security is required alongside standard entrance function.

NM8453 vs NM8050: Same Entrance Function, Different Security Level

Both the NM8453 and NM8050 are entrance mortise locks. The key difference:

NM8050 (F04): Single cylinder, entrance function, no deadbolt. Latchbolt only with toggle button control on outside lever.

NM8453 (F20): Single cylinder, entrance function, with 1" deadbolt. Adds thumbturn inside and outside key deadbolt projection to the same door prep.

If your application needs the option to fully deadbolt the door from inside at the end of the day — not just latch it — specify the NM8453.

Physical Specifications

Door thickness: 1-3/4" standard.

Backset: 2-3/4" (70mm). Field reversible — no need to specify hand when ordering.

Lockcase: Heavy gauge zinc chromate steel.

Front: Heavy gauge steel, 8" x 1-1/4" x 3/32". Accommodates flat doors and doors beveled 1/8" in 2".

Armored front: Wrought brass attached by machine screws to the lockcase front.

Deadbolt: 1" throw, hardened steel with anti-saw hardened pins.

Latchbolt: 3/4" throw, stainless steel with anti-friction reversible tongue.

Guardbolt: Extruded brass, chrome plated.

Strike: Brass, non-handed curved strike 4-7/8" x 1-1/4". Optional handed curved-up strike on request.

Center to center (lever to cylinder): 3-7/8" (98mm).

Cylinder and IC Options

Cylinder: Solid brass 6-pin, Schlage C keyway standard. Compatible with Best, Falcon, Arrow (small format IC) and Schlage (large format IC). Also accepts Medeco, ASSA, Kaba, and Cal Royal HSK high-security cylinders.

IC options: Small format IC for Best, Falcon, and Arrow. Large format IC for Schlage. All keyed functions are available with IC cores.

Keying: Master keying, grand master keying, and construction keying available.

Available finishes: US26D Satin Chrome, US32D Satin Stainless, US10B Oil Rubbed Bronze, US3 Bright Brass, US26 Polished Chrome, US4 Satin Brass.

Certifications

ANSI/BHMA A156.13-2017 Series 1000, Operational and Security Grade 1. Federal Specification Type 86. Exceeds 1,000,000 cycles. UL Listed "A" Label for 3-hour fire doors, single or pair. UL10C and UBC 7-2-1997. ADA compliant (forged brass levers, individual spring prevents lever sag). Florida Building Code approved FL13922-R8. Texas Evaluation ID DR-472. Meets Buy American Act. Lifetime warranty.