Lesson 3 in the Locksmith Training Program covers cylinder servicing as well as disc and pin types. Chapter 3 from the Locksmith Training Program Book is included as we as envelope 3-1 and 3-2. Envelope 3-1 contains a cam lock, keys and a rekeying kit. With this envelope our program teaches you step by step how to key a disc tumbler cylinder. Envelope 3-2 contains a mortise cylinder (uncombinated), cylinder springs, driver pins, bottom pins, a key and a follower tool.  Using this chapter 3 and the envelopes you will learn how to key the pin tumbler cylinder and learn an important step in understanding cylinder servicing.

In this lesson, you’ll learn about the part of the lock that keys operate: the cylinder. Cylinders come in many shapes and sizes. But they all serve the same purpose. A cylinder lets only certain keys operate the lock. So it also keeps other keys from operating the lock. 

When you have completed this lesson, you should be able to:

• Recognize the definitions of various lock cylinder terms. 
• Identify the parts of a disc tumbler cylinder. 
• Describe the functions of disc tumbler cylinder parts. 
• List three common causes of disc tumbler cylinder malfunction and describe the symptoms and remedies for each. 
• Identify the parts of a pin tumbler cylinder. 
• Describe the functions of pin tumbler cylinder parts. 
• List five common causes of pin tumbler cylinder malfunction and describe the symptoms and remedies for each. 
• Identify the three types of wafers used in Schlage Wafer locks. This segment is for enrichment only. Do not focus too much on it. These locksets should be retired.