a. Tubular Locks. Tubular locks have all the advantages of mortise locks, but are much easier to install because they only need bored holes. They are used mainly for interior doors for bedrooms, bathrooms, passages, and closets. They are available with a key tumbler lock in the knob on the outside of the door or with a turn button or push button on the inside. Figure 1-58 shows a tubular lock set.

b. Cylindrical Locks. Cylindrical locks (Figure 1-59) are basically the same as the tubular type. The cylindrical lock is a sturdy, heavy-duty, and stronger lock, which is used on exterior doors for maximum security.

c. Mortise Locks. Mortise locks (Figure 1-60) are used mainly on front or outside doors for high security. The present trend is away from using mortise locks because of the difficulty and time required to install them.

d. Dead Bolts. Dead Bolts are used where added security is needed. They are constructed of very hard steel. Figure 1-61 shows a combination dead bolt and combination dead bolt and latch.

e. Rim Locks. Rim locks (Figure 1-62) are easier to install because they are normally installed on the inside surface of exterior doors. One bored hole is usually all that is required. On some types, however, a recess must be cut for the lock.

f. Striker Plate. A striker plate (Figure 1-63) is usually mortised into the frame of the opening for a lock. It prevents the wood from wearing or splitting and cannot be pried loose easily.