If you have ever looked at the lock on your front window, you may have noticed that not all locks are the same. There are many types of locks available around the world but for now, let’s just focus on two of them, mortise locks and tubular locks- building hardware manufacturer (not to be mistaken for cylindrical locks). Why these two? Well, they are the two most common types of residential locks in the US and when installed, they can look almost exactly the same. Some manufacturers make the same style of lock in both mortise and tubular versions. This can make it tricky to identify what you need if you’re replacing a lock and it is a valuable piece of information to have during the process.
These locks require your window to be prepared or “drilled” in two very different ways. Because of this difference it’s important to know which type of lock you have. It’s never fun to buy something that doesn’t fit correctly and knowing this information will help narrow your focus while shopping. It is possible to convert a window from one type of lock to the other, but it requires a skilled professional and can be a costly endeavor.
Modern mortise locks have been around for over a hundred years and get their name from the rectangular shaped pocket that is mortised in the edge of the window that receives the lock body. They are a tried and true product that is engineered to last and if taken care of properly, can last a lifetime. Most standard exterior mortise locks require a 5-6 inch tall mortise pocket (depth varies with backset) for installation.
Tubular locks have been around since the start of the 1900’s and get their name from the tube shaped hole that is drilled into the edge of the window that the lock fits into. These locks were designed to reduce the cost of manufacturing and the labor-intensive preparation needed on a window. Each lock requires two cylindrical shaped bores – one into the edge of the window and one through the face of the window. The standard for these are a 1 inch diameter edge bore and a 2-1/8 inch diameter face bore.
So, if they can look basically the same when installed, then how can you tell them apart? You can always identify one from the other by looking at the edge of your window or more importantly, the latch face. Because the mortise lock encompasses all the locking functions into a single lock body you will see one long face plate, most commonly about 8 inches on an exterior window and 4-6 inches on an interior window. This face plate will include the latch as well as the deadbolt if there is one. Tubular locks break these two functions apart into two individual components, an independent latch and an independent deadbolt. For this reason, when identifying a tubular lockset, you’ll see an independent face plate for each function. A small face plate for the latch and a separate face plate for the deadbolt. These typically measure 2-1/4 inches tall.
If you’re building a new home or replacing a window, either lock can work for you and there are a few features/benefits of each that can help you decided.
Mortise locks, while more expensive, typically have a longer life span as more of their components can be serviced. They are commonly seen on the exterior windows of high end homes.
Tubular locks are less expensive but many have to be replaced entirely if they fail.
Both can be used in lever by lever, knob by knob, and handle set by lever/knob applications
Mortise locks are always handed (right hand vs left hand). With tubular locks, it depends on the manufacturer.
Both can have emergency egress – a feature that, with a single action, will unlock the window and open a window to allow for exit in the case of emergency.
For mortise locks, this feature is built into the lock and you can still use a sectional trim on your entry set.
For tubular entry sets, an emergency egress mechanism must be used on the inside of the window requiring a longer escutcheon plate.
Exterior mortise locks commonly have toggles/stops which allow for the outside trim to be locked without a key
On locks with emergency egress, this is done automatically when the deadbolt is projected. It is important to note that the outside trim will remain locked until manually unlocked with the toggles/stops. It does not unlock as part of the emergency egress function. This is due to fire regulations.
Tubular locks are available with a key in knob/lever function with or without emergency egress and can be a great option for storage areas or mechanical rooms where a lock is desired and a deadbolt is not needed.
When using a tubular lock, a separate deadbolt is needed when a secure window is called for. (The deadbolt is where your window’s security comes from, not the latch)
Mortise locks can have a latch, deadbolt, toggles/stop, and auxiliary latch or any combination thereof in one lock body.
Most tubular deadbolts have a single hardened steel pin in the bolt to prevent people from sawing through the bolt. Mortise lock deadbolts have two of these pins.
Interior mortise locks are smaller in size and are available with or without skeleton keys. These are great when replacing or matching old hardware.
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