What is a mortise cylinder and how does it work?
A mortise cylinder is a round, threaded key cylinder that screws into the lock body from the face of the door and is held by a set screw inside the lock. When the right key turns the plug, the cam on the back of the cylinder rotates and operates the lock mechanism. Most commercial mortise cylinders have a 1-5/32" diameter thread, as stated on the Adams Rite 4036 and Sargent listings, but the length, the cam and the keyway change from one lock to another.
Mortise cylinder vs rim cylinder
A mortise cylinder screws into the lock, while a rim cylinder is held by a back plate and screws from the inside and drives the lock with a flat tailpiece. Mortise cylinders are used on mortise locks, Adams Rite style storefront deadlocks and deadlatches and mortise exit devices. Rim cylinders are used on rim exit devices and surface-mounted rim locks. They are not interchangeable, so check the lock before ordering. If you need the other type, see our rim cylinders.
Mortise cylinder sizes: how to measure length
Measure the length of the cylinder body from the back of the face cap to the back of the cylinder, not including the cam. That length must suit the door thickness, the trim and any rose or escutcheon, so the face sits snug. The catalog lists lengths from 1" (Adams Rite 4036) through 1-1/8", 1-1/4", 1-3/8", 1-1/2" and 1-3/4", up to 2" (Corbin Russwin 1000-200 and Kaba Ilco 7325), 2-1/4" (Sargent 50) and 2-1/2" (Sargent 52). Blocking rings and compression rings make up small differences, for example the Schlage 20-013 with a 3/8" blocking ring. Our mortise cylinder sizes and cams guide has step-by-step measuring.
Cams: the part that makes a cylinder fit your lock
The cam is the tail on the back of the cylinder, and a wrong cam is the most common reason a new cylinder will not work. Each lock maker uses its own cam. Examples from the listings: Schlage L583-477 on the 20-001 for Schlage L Series, Falcon MA cams 5620, 5621 and 5622 on the Falcon 985 and 986, the Falcon M non-deadbolt cam on the 987, the Sargent offset cam 13-0664, the Adams Rite cam on the 4036 and the Schlage 26-072, and Kaba Ilco cylinders with a standard cam or a Corbin Russwin/Best clover cam.
| Brand and series | Lengths in the catalog | Cam or fit (as listed) | Notes |
|---|
| Schlage 20 and 30 Series | 1-1/8" to 1-3/4" | For Schlage L Series | C and other keyways; 20-013 with blocking ring |
| Schlage 26-072 | 1-1/8" | Adams Rite cam | For storefront deadlocks |
| Adams Rite 4036 | 1" | Adams Rite cam | For MS locks, deadlatches; 5-pin |
| Falcon 985, 986, 987 | 1-1/8" to 1-3/8" | Falcon MA cam 5620, 5621, 5622; 987 with Falcon M non-deadbolt cam | 6-pin; Schlage C keyway versions |
| Sargent 41 to 52 | 1-1/8" to 2-1/2" | Sargent offset cam 13-0664 | 6-pin, 1-5/32" diameter |
| Corbin Russwin 1000 | 1-1/8" to 2" | See listing | 6-pin |
| Accentra (Yale) 2153 | 1-1/8" to 1-3/4" | See listing | 6-pin; PARA keyway version |
| Kaba Ilco 7155 to 7325 | 15/16" to 2" | Standard, Adams Rite or clover cam | Schlage C, Sargent LA, Corbin Russwin, Yale, Kwikset and other keyways |
| Kaba Ilco 7150DC to 7280DC | 15/16" to 1-3/4" | No cam | Dummy cylinders |
Keyways, keying and master keys
The keyway is the shape of the key slot, and it must match your existing key system if the cylinder joins a master key system. Kaba Ilco mortise cylinders are listed in many keyways, including Schlage C, Sargent LA, Corbin Russwin D1, Yale, Kwikset and Segal 9, and in keyed alike, keyed alike in pairs and keyed different versions. Factory cylinders such as the Schlage 20-001 C or Falcon 985 SCH C come keyed different with two keys. Our keyways and keying compatibility guide explains which keyways cross-fit.
Dummy mortise cylinders and turn knob cylinders
A dummy mortise cylinder fills the cylinder hole without a key function, so the door face matches the rest of the opening. The Kaba Ilco 7150DC, 7160DC, 7180DC, 7200DC and 7280DC are listed from 15/16" to 1-3/4". For a cylinder operated by hand from the inside, use a thumbturn or turn knob cylinder; see thumbturns.
Mortise cylinders for electrified hardware
Some electrified locks and accessories take a standard mortise cylinder for a key override or key switch. The catalog includes the Securitron MKC conventional mortise cylinder for the MK series, the Detex MC65 for Detex alarms and the Alarm Controls CY-1. Check the hardware listing for the length and cam it calls for.
Most requested mortise cylinders
The mortise cylinders our customers look up most often right now:
Related categories: mortise locks, IC housings, interchangeable cores and storefront deadlatches.
What to have ready when ordering a mortise cylinder
- Lock brand and series (for example Schlage L Series, Sargent 8200, Adams Rite MS deadlock).
- Cylinder length, measured without the cam, and any blocking ring.
- Cam type or cam number from the old cylinder.
- Keyway, and keyed alike, keyed different or master keyed.
- Finish, such as 626 (satin chrome), and quantity.
Rekeying a building or ordering a keyed set? Request a quote for quantity pricing, and schools and agencies can submit a government or school PO. Orders placed before 3:00 p.m. ET on business days ship the same day after card approval, and ground shipping is free on orders of $450+. Not sure which cam you have? Call 718-814-6300.
The tables and selection notes on this page are compiled by National Lock Supply from manufacturer catalogs and product listings. Last reviewed: November 2026.
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