Introduction

In July of 2010, Schlage started transitioning their cylinders to a modular design. This design allowed one cylinder to be used as a key-in-lever/key-in-knob cylinder, or a rim cylinder, or a mortise cylinder, depending on the components used and their configuration.

Schlage Modular Cylinders

For example, instead of carrying 6 individual mortise cylinder lengths in a variety of finishes, you only need to have 1 cylinder with various rear and front housings. That means less costs, less overhead, less inventory; redundancy across keyways/key sections is essentially eliminated with the modular design.

The modular design also allows for field adjustments. Let’s say a customer has an area of their building renovated and they currently have modular cylinders. Let’s say they’re changing from a bright brass to satin chrome hardware. With the modular design, you would only need to change front housing on each cylinder and re-use their existing cylinders and potentially existing keys.

Schlage’s transition to the modular design lasted until February of 2011, when it became standard.



Schlage still sells non-modular cylinders and their components. There has to be hundreds of thousands of non-modular cylinders out there, if not more. It wouldn’t make much sense at all for them to simply stop supporting those products so Schlage still sells components to support non-modular cylinders and probably will be for quite some time.

Schlage Modular Components

Schlage Modular Cylinders

Multiple different components make up Schlage’s modular design:

  • Cylinder. The cylinders used for the modular design were new to Schlage. They are backwards compatible, so to speak, in that they can be used in hardware that pre-dates the modular design. The same cannot be said for key-in-knob/key-in-lever cylinders that predate the modular design; they cannot be used with other modular components. There are 2 reasons for this: one is a dimensional change to the cylinder’s bible and the second is the horizontal notch at the back of the plug that interfaces with the cam. During the transition period and for a while after it, a green highlighter on the cylinder and packaging label marked a modular cylinder. It appears that Schlage has since discontinued this marking; it’s been almost 10 years since the rollout after all. One final note, Classic, Primus, Everest, Primus XP, Everest 29, all keyway families are offered in the modular design.
  • Front Housing. The front housing is the same size no matter the cylinder type/size. It’s available in all finishes offered by Schlage.
  • Rear Housing. Rear housings are available to create 1-1/8”, 1-1/4”, 1-3/8”, 1-1/2”, 1-5/8”, 1-3/4” mortise cylinders. The rear housings are color coordinated in either gold or silver colors. All cylinder lengths ending in an 8th of an inch are gold, so 1-1/8” 1-3/8” and 1-5/8” rear housings are gold. 1-1/4” 1-1/2” and 1-3/4” are silver. Rim cylinder rear housings only come in one length.
  • Housing Screws. Housing screws secure the rear housing to the front housing. They are the same size no matter the cylinder size; larger rear housings just have recesses to accommodate them.
  • Cam. Cams are not interchangeable across the entire modular product line. 1-1/4”, 1-1/2”, and 1-3/4” cylinders all use one cam and 1-1/8”, 1-3/8”, and 1-5/8” cylinders use another cam. Fortunately, these sizes are marked on the back of each cam. Cams have one screw hole except the Straight Cams (L583-476 and L583-477) which contain two screw holes. The second screw hole allows the cam to be inverted, which is usually necessary on key switches.
  • Cam Screw. Cams are held in place with Torx head screws. This switch was largely influenced by customer feedback. Customers were tired of dealing with stripping issues that were common with Philips head screws.
  • Plug Extension Kit. There are two plug extension kits. The long plug extension kit is used for 1-5/8” and 1-3/4” cylinders. The short plug extension kit is used for 1-3/8” and 1-1/2” cylinders.

All modular components are available to be ordered separately.

Schlage Modular Cylinders

Identifying Schlage Modular Cylinders

The various components assist with quickly narrowing down the cylinder length without a ruler. The cam or the color of the rear housing tells you which 3 of the 6 total cylinder lengths you’re dealing with (either 1-1/8”, 1-3/8”, and 1-5/8” OR 1-1/4”, 1-1/2”, and 1-3/4”) . The length of the plug extension kit, or the lack of one, allows you to narrow the cylinder length from 3 down to 1.

Additional Information

Schlage Modular Cylinders Catalog

2020-02-22T21:51:44-05:00 January 20th, 2020|All, Cores and Cylinders|

About the Author:

I am the Vice President of Security Engineering Consultants in Atlanta, GA, USA. I am a member of ALOA, the Clearstar Security Network, Locksmith Nation, and the Locksmith Security Association of Michigan. Email me here or follow me on Twitter.

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