This guide reflects CDF Distributors' standard specifications and field-tested recommendations used by commercial contractors nationwide. The information is provided for specification and selection purposes. Always verify requirements with the Authority Having Jurisdiction (AHJ) for your project location.

For questions or to order a complete door assembly, contact CDF at (855) 769-9895 or sales@cdfdoors.com. Configure your assembly online at ProBuilder: cdfdistributors.com.

About This Guide

What is the main structural difference between a cylindrical and mortise lockset?

A cylindrical lockset mounts through two bored holes in the door (a cross-bore and an edge-bore), with the lock chassis seated in the cross-bore. A mortise lockset mounts inside a rectangular pocket cut into the door edge, with a self-contained steel lock body that houses the entire latch and deadbolt mechanism.

Is a mortise lock more secure than a cylindrical lock?

At the same ANSI grade level, a mortise lock body provides greater mechanical resistance to forced entry due to its heavier steel construction and integrated deadbolt. However, both types are available in Grade 1 configurations that meet institutional security requirements. The specification should match the lock type to the threat level and traffic volume of the opening.

Can I replace a cylindrical lockset with a mortise lockset on an existing door?

Converting from cylindrical to mortise requires cutting a mortise pocket into the door edge and filling the existing cross-bore. This is feasible on solid-core wood doors but may not be practical on hollow metal doors. It is generally more cost-effective to replace the entire door if a mortise lock is required on an opening originally prepped for cylindrical hardware.

What ANSI grade should I specify for a commercial classroom door?

Most jurisdictions and school districts require ANSI/BHMA Grade 1 locksets with classroom function (F05) for classroom doors. Grade 1 provides durability and the strength ratings necessary for institutional use. Classroom function allows key-operated locking from the corridor side while maintaining free egress from the interior.

Does CDF supply both cylindrical and mortise locksets?

Yes. CDF Distributors supplies cylindrical and mortise locksets from Accentra (Formerly Yale), Corbin Russwin, Harger, Sargent , Schlage, and many other brands. Both lockset types can be configured in CDF's ProBuilder tool as part of a complete door, frame, and hardware assembly.

What lock function should I use for a storeroom door?

Storeroom function (F07) is the standard specification for storage rooms, electrical rooms, and other restricted-access openings. The exterior lever is always locked and requires a key for entry. The interior lever is always free for egress. This function is available in both cylindrical and mortise configurations.

Frequently Asked Questions

CDF's ProBuilder tool allows you to configure complete door assemblies with your choice of cylindrical or mortise locksets. Select the lock type, function, finish, and keying to receive a validated, code-compliant assembly quote. For assistance, call (855) 769-9895 or email sales@cdfdoors.com.

Configure Your Door Assembly

CDF Distributors supplies cylindrical and mortise locksets from Accentra (Formerly Yale), Corbin Russwin, Harger, Sargent , Schlage, and many other brand names. Our many vendor relationships provide access to the full catalogs of ANSI-certified lock functions, finishes, and keying options from all of the most desired commercial lock brands.

CDF's ProBuilder configuration tool allows specifiers to select the lock type (cylindrical or mortise), function, finish, and keying as part of a complete door assembly. ProBuilder validates that the selected hardware is compatible with the specified door and frame, ensuring a code-compliant assembly. Locksets can be ordered as part of a pre-assembled door package or as standalone hardware.

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Cylindrical locksets have a lower unit cost and lower installation labor cost due to simpler door preparation. Mortise locksets carry a higher unit cost and require more skilled installation labor, but their self-contained steel lock body provides superior resistance to wear, abuse, and forced entry.

Over the lifecycle of a high-traffic commercial opening, mortise locksets often prove more cost-effective because the lock body outlasts the trim and cylinder. Trim and cylinders can be replaced independently without removing the lock body from the door. Conversely, cylindrical locksets may require full replacement when the chassis wears.

For moderate-traffic interior openings, cylindrical locksets provide adequate performance at a lower initial investment. The specification decision should weigh initial cost against expected traffic volume, security requirements, and lifecycle maintenance costs.

Cost and Durability Tradeoffs

Mortise locksets are specified when the opening demands maximum durability, integrated deadbolt and latch functions in a single lock body, or increased security standards are desired. Typical applications include:

• High-traffic main entries and vestibule doors

• Healthcare facilities (patient rooms, operating suites, pharmacy)

• Government and institutional buildings

• Hotels and hospitality facilities

• Applications requiring field-reversible handing without disassembly

• Doors where the lock body must withstand sustained abuse or forced-entry attempts

When to Specify Mortise Locksets

Cylindrical locksets are appropriate when the application calls for a cost-effective, easy-to-install lock that meets commercial-grade requirements without the additional strength and complexity of a mortise body. Typical applications include:

• Interior office doors with moderate traffic

• Classroom doors (Grade 1 cylindrical with classroom function)

• Storage and utility rooms

• Multi-family residential corridors and unit entries

• Retrofit projects where existing door prep is bored (cylindrical) configuration

• Budget-sensitive projects that still require ANSI Grade 1 or Grade 2 performance

When to Specify Cylindrical Locksets

Lock function describes the operational behavior of the lockset—how the latch and deadbolt respond to the lever, key, and thumbturn. Both cylindrical and mortise locksets are available in a wide range of functions. The most commonly specified commercial functions include:

• Passage (F01): Latch retracted by lever from either side. No locking. Used for corridors, mechanical rooms, and public-access openings.

• Privacy (F19): Latch locked by interior pushbutton or thumbturn. Unlocked from exterior with emergency tool. Used for restrooms and private offices.

• Office (F04): Latch locked or unlocked by interior thumbturn; exterior lever always operable when unlocked. Key overrides from exterior. Common in standard office doors.

• Classroom (F05): Latch locked and unlocked by key from exterior only. Interior lever is always free for egress. Required for classroom lockdown compliance in many jurisdictions.

• Storeroom (F07): Exterior lever is always locked; entry by key only. Interior lever is always free for egress. Used for storage rooms, electrical rooms, and restricted-access areas.

• Entrance (F10): Deadbolt controlled by thumbturn (interior) and key (exterior). Latch retracted by lever from either side. Used for main entries and exterior doors.

• Apartment (F12): Deadbolt controlled by thumbturn (interior) and key (exterior). Exterior lever locked by key; interior lever always free. Common in multi-family units.

Common Lock Functions

Both cylindrical and mortise locksets are tested and certified under ANSI/BHMA A156 series standards. Grade ratings measure cycle life, strength, and security. Understanding these grades is essential for specification.

Grade 1 (Heavy-Duty Commercial)

Grade 1 is the highest ANSI/BHMA rating and is required for high-traffic and high-security applications. Cylindrical Grade 1 locks must pass 800,000 cycles. Mortise Grade 1 locks must also pass 1,000,000 cycles. Grade 1 products meet the strength and security thresholds required for institutional, healthcare, and government facilities. Both Yale and Corbin Russwin produce Grade 1 products in cylindrical and mortise configurations.

Grade 2 (Standard Commercial / Heavy Residential)

Grade 2 cylindrical locks are rated for 400,000 cycles, where grade 2 mortise locks are rated at 800,000 cycles. They are appropriate for standard commercial office environments, light-traffic corridors, and multi-family residential applications. Grade 2 represents a lower cost point while still meeting commercial durability standards.

Grade 3 (Residential)

Grade 3 locks are rated for 200,000 cycles and are intended for residential use. They are generally not specified for commercial projects, though they may appear in low-traffic auxiliary openings. Grade 3 mortise locks are rated for 800,000 cycles.

ANSI/BHMA Grade Ratings

A mortise lockset installs into a rectangular pocket (mortise) cut into the edge of the door. The lock body is a self-contained metal case that slides into this pocket and is secured with mounting hardware. Exterior and interior trim (levers, knobs, thumbturns, cylinders) mount to the door face and connect to the lock body through the door.

The mortise lock body contains the entire latch and deadbolt mechanism within its metal case. This self-contained design provides greater mechanical strength and allows for more complex lock functions within a single unit. The tradeoff is a more involved door preparation—mortise pockets require precise routing or chiseling.

• Mortise pocket: The standard mortise pocket (86 prep) in a commercial door is sized at 1-1/4" x 8" (32 mm x 203 mm). This varies by manufacturer.

• Lock body: Self-contained metal case with integrated latch and deadbolt

• Door prep: Mortise pocket plus face holes for trim and cylinder, varying widely across brands, functions and lock models .

• Internal mechanism: Latch, deadbolt, and auxiliary functions all within the lock case

• Replacement: More flexibility in replacing components instead of the entire lock body.

Mortise Lockset Construction

A cylindrical lockset installs through two bored holes in the door: a large cross-bore (typically 2-1/8 inches in diameter) through the face of the door, and a smaller edge-bore (typically 1 inch) through the door edge for the latch. The lock chassis sits inside the cross-bore, and the two halves of the lock (interior and exterior trim) connect through the door using a spindle or tailpiece.

Because cylindrical locks rely on the bored hole for structural support, the lock body itself is relatively compact. Installation is straightforward and requires only a hole saw and a standard latch prep. This makes cylindrical locksets the default choice for interior office doors, classroom doors, and other moderate-traffic openings.

• Cross-bore diameter: 2-1/8 inches (standard)

• Edge-bore diameter: 1 inch (standard)

• Typical door prep: Two bored holes plus strike prep

Cylindrical Lockset Construction

Commercial doors often require locksets engineered for high-cycle use, institutional security, and code compliance. The two dominant lockset families in commercial construction are cylindrical (also called bored) locksets and mortise locksets. Each uses a fundamentally different mounting method, internal mechanism, and chassis design. Selecting the correct type depends on traffic volume, security requirements, fire rating, and budget constraints.

CDF Distributors stocks both cylindrical and mortise locksets from Accentra (Formerly Yale), Corbin Russwin, Harger, Sargent , Schlage, and many other brand names. All of these manufacturers produce ANSI/BHMA-certified products across multiple grade levels, allowing specifiers to match the lockset to the application.

Overview of Commercial Lockset Types

A specification guide to cylindrical and mortise lock construction, ANSI grades, lock functions, and selection criteria for commercial door assemblies.

This guide answers: What is the difference between cylindrical and mortise locksets for commercial doors?