Compare mortise and cylindrical locks for commercial doors. Learn the differences in durability, cost, and where each lock type is most effective.
The differences between mortise locks vs. cylindrical locks can be straightforward. A cylindrical lock mechanism is contained in a cylindrical shell called a chassis, while a mortise lock’s mechanism is contained within a mortise case.
However, the choice between the two isn’t always simple. The way both locks are designed impacts everything from installation to durability and price. The best solution involves assessing your needs with these factors in mind.
What Are Cylindrical and Mortise Locks?
Before we can compare mortise and cylindrical locks, we need to first talk about what a mortise lock and a cylindrical lock are.
Cylindrical Locks
Cylindrical locks have an internal mechanism housed within a cylinder, often referred to as a chassis. This chassis fits through a bored hole in the door, with additional holes drilled for through bolts and a door latch. Cylindrical locks can be identified by the characteristic key-in-lever outside trim. Cylindrical locks are common in both residential and commercial settings.
Mortise Locks
Mortise locks differ because of their shape as well. Instead of a cylinder housing the mechanics of the lock, a mortise case holds them instead. The door is prepped by mortising a rectangular pocket into the edge of the door to accommodate this case (thus the name “mortise” lock) and drilling holes into the inside and outside faces of the door to receive any variety of functional trim. Unlike the key-in-lever characteristic of cylindrical locks, the mortise lock typically includes a separate keyed cylinder in the outside trim. Another distinguishing feature of a mortise lock is that some functions can also incorporate a deadbolt for added security. These types of locks are sometimes found in older, higher-end residential buildings or commercial buildings, although they have become more popular in recent years.
Mortise Locks Provide More Security (With One Condition)
Because of the sturdy, metal mortise case housing the lock, mortise locks are often considered to be more secure than cylindrical locks. In 2022, the FBI reported 847,522 break-ins. 56% of these break-ins happen via the front or back door. A mortise lock better protects against these attempts.
For those who want to kick down the door, the heavy metal mortise case often adds even more durability to the door slab, especially in mortise lock functions that include a deadbolt. However, there is one condition to this.
Finding the Right Door
Installing a mortise lock could actually weaken the door. The ANSI standard for mortise locks recommends a minimum door thickness of 1-⅜ “ or 35 mm.
Mortising a hole in the edge of the door to receive the mortise case in a door any thinner than this creates a risk of weakening the door. The door won’t be able to accommodate the lock and could crack. Should someone attack the door, the door could also split where it has been mortised.
Cylindrical Locks Are Easier To Install
Because a cylindrical lock usually only requires holes to be bored into the door, it is much easier to install than mortise locks.
For mortise locks, a spade bit is usually used to bore multiple holes in the edge of the door to begin the mortise pocket prep to receive the lock case. Once drilled, a chisel is used to square out the pocket to best fit the lock. A router then mortises the latch plate into the edge of the door. The appropriate holes to accommodate the trim are then drilled into the inside and outside faces of the door.
For both types of locks, the manufacturer often provides templates to make measuring for door prep easier. OAK Security even offers some jigs for the cylindrical and mortise locks we provide.
Mortise Locks Are More Durable
Mortise locks can last for decades and are sometimes considered a better option for high-traffic areas like hospitals or exterior doors. In fact, ANSI/BHMA literature will often refer to mortise locks as high-performance locksets.
When measuring a mortise lock’s durability, the amount of torque the lever can withstand, the number of blows to the lock face, and the types of materials all must reach certain standards for it to qualify as a commercial Grade 1 mortise.
Cylindrical Locks Are More Affordable
Despite mortise locks being considered a more robust lock, cylindrical locks are easily more affordable. However, there are more costs associated with purchasing a new lock besides the cost of the lock itself.
Product Costs
Cylindrical locks are almost always more affordable than mortise locks. However, the cost of materials, the complexity of design, and the sheer size of locks all contribute to mortise locks’ higher cost.
Installation Costs
When considering the purchase of a lock, the cost for installation should be considered as well. Whether you are paying someone else to install the lock for you, or you’re handling the installation yourself, a great deal of time and resources go into installing a mortise lock over a cylindrical lock. Because of the complexity that comes with chiseling out a section of the door for mortise locks, installation can cost more.
Another factor that comes with installation costs is what lock your door has previously used. If your door has already been prepped for a mortise lock and you’re considering switching to a cylindrical lock, keep in mind that you will likely need to purchase a door wrap-around plate to prepare the door for a new lock.
Maintenance Costs
Maintenance costs are an instance where mortise locks are more affordable than cylindrical locks. Because of the durability of mortise locks, these devices will likely last much longer before maintenance is required compared to a cylindrical lock.
Even if your cylindrical lock never requires maintenance, it will likely need to be replaced before a mortise lock does. A critical evaluation of your doorway will be required to determine if a cylindrical can last the length of time you need it to. Otherwise, you may find yourself spending more money buying multiple cylindricals than you would investing in a single mortise.
Making the Right Choice
Even though each lock certainly has its strengths, there is no perfect lock for every application. Both locks have grown in public interest over recent years.
It may be tempting to install the beefiest lock on a door to avoid wrestling with the decision, but careful examination of your needs and each product can prevent a lot of headaches down the road.
If you’re unsure where to start, we’re here to help! We offer complimentary consulting services to help you evaluate your existing lock system and determine the best solution. You can give us a call at 317-585-9830 or fill out our contact form to have a representative meet you at your site.