Mortise vs. Tubular Style Locks
When you consider hardware, there are two different and distinct types of locks: tubular style and mortise style. One is more secure, and the other is more popular. And while one is easier to install, the other requires special equipment. But which is which?
The tubular style lock is commonly found on all types of doors, most notably interior residential and office doors. It boasts excellent security for most applications and is usually quite easy to install and replace if standard bore holes are already cut in the door. Make sure your new latch has the correct backset length (the measurement from the edge of the door to the center of the bore hole), and just follow the installation instructions. The most popular types of tubular style locks are single cylinder and double cylinder.
A mortise style lock is the most secure form of an entry set. The reason? A special cut in the door allows a longer and thicker mortise to slide into the pocket in the door itself, providing superior protection. These types of locks require special door preparation, so if your door isn't currently cut to fit this kind of lock, you (or a professional installer) will need to use a mortise saw to cut into the door so the lock fits properly. Take note that not all mortise locks have the same dimensions. So prior to any door alteration, take careful measurements. This kind of lock was commonly seen in homes prior to 1940 (before the introduction of bored cylindrical locks), but is still available today in single cylinder, double cylinder, and dummy set.