Lesson 2: Tools, Locks, and Keys - Part 2

Types Of Key Operated Locks

The International Association of Home Safety and Security Professionals defines a lock as “a device that incorporates a bolt, cam, shackle or switch to secure an object – such as a door, drawer or machines – to a closed, opened, locked, off, or on position, and that provides a restricted means of releasing the object from that position.” In this section we will be discussing some of the ‘usual suspects.’ The most commonly encountered key operated locks will be discussed below. Most of the key operated locks use pin and tumblers to engage with the key unless otherwise stated. Greater specificity will be given to each lock as we learn to service them in later chapters.


  • Grade 1: Commercial grade locks
  • Grade 2: Residential and light commercial use.
  • Grade 3: Residential use

There are many different types of deadbolts and handle sets available. Each has its own purpose and it’s important to know what that is. One of the distinctions you need to make is about the grade of the lock. The grade of the lock is determined by manufacturer’s standards and refers to testing on 3 factors.

Operational Test

examines the amount of torque needed to retract the latch bolt with and without the key. For key-in-knobs to receive a grade, toque used may not exceed 9 lbf-in. For lever handles, torque may not exceed 28 lbf-in. For all locks, to turn the latch and retract the bolt, torque may not exceed 9 lbf-in.

Strength Test

examines how much turning force a lock in the locked position can withstand. For grade 1, a key-in-knob must withstand 300 lbf-in; a lever lock must withstand 450 lbf-in. For grade 2, a key-in-knob must withstand 150 lbf-in; a lever lock must withstand 225 lbf-in. For grade 3, a key-in-knob must withstand at least 120 lbf-in, and a lever lock must withstand at least 180 lbf-in.

Cycle Test:

determines how many the lock can be operated before failure. For grade 1, a lock must complete 800 000 cycles. For grade 2, a lock must complete 400 000 cycles. For grade 3, a lock must complete at least 200 000 cycles. Colloquially speaking, most locksmiths refer to grades in a tier system: knock offs, residential, commercial, and high-security. High security locks offer the maximum amount of security. These locks have commercial grade durability along with the greatest degree of access control. High security features include exclusive keyways, pick proof locking mechanisms and drill resistant hardware. Knock off locks don’t have a brand name and are often made offshore. They are made from cheap parts and materials and will not survive an attack or lengthy period of use. As a rule, locksmiths do not carry knock off grade locks in stock. When you encounter them on the job, you should suggest to your customer that they upgrade their locks.

Deadbolt Deadbolt

By far the most commonly encountered door lock is the deadbolt. Deadbolts come in a range of styles and manufacturers, but all deadbolts contain a key operated cylinder within a metal shrouding and a retractable bolt or latch that engages with the frame. Most deadbolts have a thumb turn which engages the bolt from inside the house, and a keyway on the outside. Double cylinder deadbolts have a keyway on both sides of the door. A deadbolt lock is one of the securest locks you will find on an external doorway. As a member of the security industry, you should insist that every external door be outfitted with a deadbolt. A locksmith will supply, install, repair, rekey, upgrade, pick, and drill these locks on a regular basis.

Handle sets Handle sets

These are used for opening and closing doors. They are spring loaded and retract the latch by turning the knob. There are many different types of handle sets and you will need to know them all. Knobs and levers are dismantled differently and have different purposes. As well we will discuss the different functions of handle sets.

Key-in-knob Key-in-knob

A key in knob is one of the most common locks on people’s homes. It is a handle set with a locking mechanism built into it.

Lever lock Lever lock

A lever lock is the same as a key-in-knob but with a lever handle instead of a knob. Knob and a lever handle are dismantled differently.


  • Passage Set:

    This is your standard handle set. There is no locking mechanism. The latch bolt can be released by either handle.

  • Entrance Set:

    The lock is in the unlocked position unless the outside key or internal lever locks the outside knob.

  • Privacy Function:

    you see this most often on bedroom and bathroom doors. On one side is the thumb turn which engages the locking mechanism, on the other side is a small hole. You can insert a poking device into the hole to disengage the lock.

  • Storeroom Function:

    You see this most often in storage rooms and lockers. The lock handle is always in the locked position. The latch can be retracted by a key on the outside.

Mortise cylinder Mortise cylinder

A mortise cylinder is a keyway within tube shaped housing. The keyway rotates a tailpiece at the back of the cylinder. Generally there are 2 sizes of mortise cylinder and they come in many keyways. They have threading so they can be removed, replaced, or reintegrated easily. On residential doors, mortise cylinders engage with the mortise lock, a structure that remains inside the door. On commercial doors, mortise cylinders engage with the Adams Wright.

Rim cylinder Rim cylinder

A rim cylinder is similar to a mortise cylinder with a few differences. Rim cylinders do not have a threading and instead or fastened to the locking device with screws. Additionally, rim cylinders have a long flat tailpiece which engages with the Jimmy proof lock. The Jimmy proof or drop bolt lock uses an interlocking bolt. Most often you see these on security gates.

Padlocks Padlocks

A padlock is a detachable look which uses a swinging hook and a locking mechanism. Once considered a low-security option, today padlocks come in all grades including high-security.

Mailbox locks/ desk locks Mailbox locks/ desk locks

Mailbox locks and desk locks are small wafer locks. They have hundreds of different tailpieces in use today, making them very versatile in its application. These locks are a low security option.