Cylindrical locks are the most common commercial lockset in the country, and also one of the most misunderstood, mostly because people assume all lever locksets are basically the same. They're not, and the differences matter for both security and code compliance.
What Makes a Lock "Cylindrical"
A cylindrical lock, sometimes called a cylindrical door lock or bored lock, is defined by how it's installed. Two round holes are bored through the door, one through the face for the lever or knob mechanism, and one through the edge for the latch. This is different from a mortise lock, which requires a rectangular pocket cut into the door edge and is generally a more labor-intensive, higher-cost installation. Cylindrical locks are faster to install and service, which is a large part of why they dominate office buildings, schools, and multifamily housing.
Cylindrical Lever Lock vs Knob Lock
Most commercial cylindrical locks today use levers rather than round knobs, largely because ADA accessibility guidelines require operable parts that don't require tight grasping or twisting to use. A cylindrical lever lock can be opened with a closed fist, an elbow, or minimal grip strength, which knob-style hardware cannot reliably offer. Nearly all new commercial installations in the U.S. now specify lever hardware for this reason.
Understanding Lock Grades
Cylindrical locks are graded by ANSI/BHMA standards, Grade 1 through Grade 3. Grade 1 is the highest security and durability rating, standard for commercial entries, high-security areas, and heavy-traffic doors. Grade 2 covers lighter commercial and heavier residential use. Grade 3 is standard residential grade. Specifying the correct grade for the application isn't just about durability, it's often a code or insurance requirement for commercial occupancies.
Cylinder Security and Lock Picking Resistance
Cylindrical lock security largely comes down to the pin tumbler mechanism inside the cylinder. Standard pin tumbler cylinders can be vulnerable to picking or bumping with basic hand tools, which is why higher security applications use cylinders with additional security pins, tighter tolerances, or restricted keyway systems that make unauthorized key duplication and picking significantly more difficult. For any application protecting sensitive areas, IT rooms, pharmacy storage, records rooms, upgrading to a high-security cylinder is a relatively low-cost way to meaningfully raise the security level of an existing cylindrical lockset without replacing the whole unit. This is general security background for specification purposes, not a guide to bypassing hardware.
Cylinder Door Lock Replacement Basics
Most cylindrical lock failures come down to one of three components: the cylinder itself, the lever return spring, or the chassis inside the door. A lock that turns freely without retracting the latch usually has a worn chassis, not a cylinder problem, and replacing just the cylinder won't fix it. Diagnosing which component actually failed before ordering parts saves a second shipping delay and a second service call. Schlage's B-series and ND-series cylindrical locks account for a large share of the installed base in commercial buildings, and full parts diagrams for cylinders, chassis, levers, and strike plates are available through cylindrical lock parts, which is the fastest way to confirm the exact component before ordering.
Rekeying vs Replacing
When a building changes tenants or loses control of keys, rekeying the existing cylinder is almost always faster and cheaper than replacing the entire cylindrical lockset, as long as the chassis and lever mechanism are still functioning correctly. Full replacement only makes sense when the lockset itself has failed mechanically or the building is upgrading to a different security grade or keying system.
For entries that combine a cylindrical lock with panic hardware, which is common on stairwell doors and secondary exits, see our guide to rim exit devices , since code requirements for combining locking and egress hardware on the same door are specific and easy to get wrong.
Frequently Asked Questions
What's the difference between a cylindrical lock and a mortise lock?
Cylindrical locks install through two bored holes and are faster and cheaper to install. Mortise locks require a pocket cut into the door edge, cost more to install, but generally offer stronger construction for high-security applications.
Are all cylindrical locks ADA compliant?
Lever-style cylindrical locks are ADA compliant. Round knob versions are not, since ADA guidelines require hardware operable without tight grasping or twisting.
How do I know if I need Grade 1 or Grade 2 hardware?
Grade 1 is standard for commercial entries and high-traffic doors. Grade 2 is acceptable for lighter-use interior commercial doors. Local code or insurance requirements sometimes dictate minimum grade regardless of traffic level.
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