Views: 10 Author: Site Editor Publish Time: 2026-02-12 Origin: Site
A round mortise lock—often called a circular mortise lock or cylindrical lock body—is a high-performance door locking system installed inside the door edge through a precisely cut pocket known as a mortise. Unlike surface-mounted locks or standard bored locks, this type of lock integrates seamlessly into the door structure, with only a sleek round faceplate visible on the edge. The internal mechanism typically includes a latch bolt, deadbolt (in security models), spring-loaded components, and a key cylinder—all enclosed within a durable metal housing. This design not only enhances the door’s structural integrity but also delivers a clean, minimalist look that aligns perfectly with modern architectural aesthetics. Round mortise locks are commonly used in premium residential doors, office entrances, hotels, and commercial buildings where both form and function are critical.
1.Why High-Quality Round Mortise Locks Matter – The Degol Standard
Not all round mortise locks are created equal. Performance, material quality, and precision engineering determine how well a lock functions over time—and this is where Degol sets the benchmark. Degol round mortise locks are manufactured using high-grade stainless steel and hardened brass components, ensuring exceptional resistance to corrosion, wear, and physical stress. Each unit undergoes rigorous testing for durability, smoothness, and security compliance, meeting international standards for both residential and commercial use. The latch and bolt mechanisms are engineered for silent, fluid motion, while the precise tolerances guarantee perfect alignment with strike plates—even after years of daily use.
| Parameter | Description | Common Specification |
| Product Model | Model Number | Standard Round Mortise Series |
| Material | Lock Body Material | Zinc alloy, Stainless steel, Iron |
| Finish | Surface Treatment | Satin nickel, Polished chrome, Matte black, PVD gold |
| Lock Body Type | Lock Case Type | Round mortise lock |
| Backset | Distance from door edge to spindle | 40 mm, 45 mm, 50 mm, 60 mm |
| Lock Body Diameter | Round lock case diameter | Ø48 mm, Ø52 mm |
| Lock Body Length | Overall length of lock body | 80 mm, 85 mm, 90 mm |
2. Can the rounded head lock replace the original square head lock?
Yes, but there will be a gap. If you replace the square head lock with the rounded head lock, the original straight edge area on the door edge will have a gap.
It won't work the other way around: The square head lock cannot be directly inserted into the rounded head slot; it must be chiseled to make the rounded corner into a straight angle.
3. What are "center distance" and "back distance"? (Required for lock replacement)
These are the two core dimensions of the rounded head plug-in lock. Buying the wrong one will definitely not fit:
Backset (Back Distance): The distance from the edge of the door to the center of the keyhole (commonly 45mm, 55mm, 60mm).
PZ Distance (Plug-in Zone Distance): The distance from the center of the handle shaft to the center of the lock cylinder arc (commonly 72mm, 85mm).
4. How secure is the rounded head lock?
The core lies in the lock body material: The rounded head is only the shape of the panel. Security depends on the internal structure of the lock body (whether it is anti-sawing, anti-picking) and the grade of the matching lock cylinder.
Recommendation: Look for models with 304 stainless steel panels and anti-pull-out function latches.
5. Can the direction of this lock be changed? (Latch direction change)
Yes. The majority of rounded head plug-in locks have reversible latches. Usually, simply push in the latch and rotate 180 degrees, or turn the small switch on the side of the lock body.
Moreover, Degol’s locks feature anti-drill plates and reinforced cylinders to deter common break-in techniques. Designed for seamless integration with modern door systems—including pivot hinges and smart access controls—Degol round mortise locks deliver unmatched reliability, safety, and aesthetic refinement. For architects, builders, and homeowners who demand excellence, Degol represents the gold standard in circular locking technology.
