Servicing Schlage Primus / Primus XP Lock Cylinders

With the correct tools, keying a Primus lock cylinder can be completed in a minimum amount of time for maximum profit.


Schlage introduced the Primus high security lock cylinder during the fourth quarter of 1988. Schlage Primus was introduced with key-in-knob/lever, rim and mortise lock cylinders. The Primus cylinder is a modified six-pin tumbler conventional Schlage lock cylinder. A sidebar operated by five finger...


To access the remainder of this piece of premium content, you must be registered with Locksmith Ledger. Already have an account? Login

Register in seconds by connecting with your preferred Social Network.

OR

Complete the registration form.

Required
Required
Required
Required
Required
Required
Required
Required
Optional
Required
Required

If the lock cylinder is master keyed, determine the depths of the bottom pins and master pins. Insert the bottom pins first. Then place the master pins above the bottom pins in their respective positions. Insert the first key into the plug. The bottom pins (and some or all of the master pins if equipped) will align at the outer diameter of the plug. If all of the master pins do not align, note which positions that do. Insert the second key, the master or a change key and make sure all of the master pins for one or the other key align at the outer diameter of the plug.

Once the keys have been checked, the next step is to unload the top pins from the shell. This is important because Schlage has three lengths of top pins to keep the pin stacks balanced. Size number one is .235” and is designed for plug total per chamber of 0, 1, 2 or 3. Size number two is .200” and is designed for plug total per chamber of 4, 5 or 6. Size number three is .165” and is designed for plug total per chamber of 7, 8 or 9. Plug total includes the size of the bottom pin and any master pin.

When loading the shell, use new springs with the correct top pins, remove the springs and replace them.

Now the plug is ready to be inserted into the shell. Before inserting the plug, make sure the edge of the shell’s bible that will contact the plug face is the flat edge. The angled edge is next to the cap. If the plug is inserted backwards, the key will not be able to be removed.

Insert the plug into the shell with the pin chambers at approximately a 45-degree angle to each other. This way, if the lock cylinder is master key, there is no possibility any of the top pins will slide into a pin chamber.

Position the plug with the keyway vertical. Place the rear of the plug against the flat end of the follower and gently put pressure against the follower.

Carefully continue to place gentle pressure against the follower until the plug sides into the shell. Carefully test the operation of the lock cylinder. When satisfied, remove the key and insert the cap spring, cap pin, driver and install the cap. Snug the cap in place. Too tight, the key may not enter the keyway. Too loose, the key may not be able to be removed. Test the operation of the keys and assemble the lock cylinder.

Test the operation of the lock cylinder with each key.

Drawings for this article were obtained from the Schlage Primus© Service Manual © 2010. For more information, contact your local locksmith distributor or Schlage Lock, Web Site: http://w3.securitytechnologies.com.

We Recommend