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...
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Note: Primus and Primus XP CP, CEP, EP, EFP, FP and FGP keyways can be used with Classic Schlage cylinders using the obverse (C, E, F, G) keyways. The Primus keys with the same obverse keyway are compatible. For example, a “C” keyway Primus key is designed to enter the “C” keyway Classic lock cylinder and if compatibly combinated, operate these lock cylinders. The conventional “C” keys will not enter or operate Primus lock cylinders.
Primus and Primus XP lock cylinders can be identified from the front by the word Primus stamped into the plug face. Primus mortise, rim and modular mortise and rim cylinders have a single screw securing the cam onto the plug assembly. Schlage classic mortise and rim cylinders have two screws. Classic key-in-lever cylinders tailpieces have notches for locating the driver bar vertically or horizontally at approximately 11 and 2 o’clock. The 11 o’clock position is vertical.
Primus key-in-lever cylinders tailpieces have notches for locating the driver bar vertically or horizontally at approximately 7 and 2 o’clock. The 2 o’clock position is vertical. The Primus modular KIK and KIL lock cylinders have only one notch at approximately 2 o’clock.
Changing the combination on a Primus lock cylinder requires removing and replacing the top, master and bottom pins as the top pin are sized for different pin lengths. Replacing any or all of the five finger pins is only necessary if the keys have been replaced using a different side bitting.
Servicing and changing the six pin tumblers’ combination on a Primus lock cylinder requires maintaining the finger pins and the spring loaded side bar in their proper locations. The finger pins load from the bottom of the plug. When loading an empty plug or changing or replacing the finger pins, they can be loaded with the plug in the Schlage plug holder.
Schlage Primus lock cylinders are not designed for top loading. A flat brass spring retainer is crimped into place. Removing the spring retainer is not advised for combination changes.
Recommended tools for changing the combination of a Schlage Primus lock cylinder are:
Schlage Primus Plug Holder or similar tool that has a groove in at least one side of the inside diameter. This groove is required in order to insert or remove the key while the plug is in the plug holder. If there is no groove, the key cannot be removed, as the side bar must be able to extend to the locked position as the key is being removed.
Schlage Follower with a section cut out in order to remove any master pin without having to completely unload the shell. The removed section of the follower is not large enough for a top pin to exit a pin chamber.
If the lock cylinder is equipped with a screw or screws securing the cam, a Phillips head screwdriver is necessary.
To simplify the combination change, a Cap Removal Tool depresses the cap pin and permits removal of the cap without have to depress the pin.
A pair of locksmith pin tweezers that have the tip either formed or machined to accommodate a pin tumbler.
A Key Gauge is needed for standard Schlage depths of cut.
Important: When changing the combination, be extremely careful, a plug holder is recommended to maintain pressure on the side bar. If pressure is not maintained on the side bar, it will spring out and the two side bar spring are difficult to find especially if you only have those two springs.
For this article, I will load and assemble a key-in-lever lock cylinder using the key.
The first step is to insert the empty plug into the Schlage Loading Tool. Then insert the two side bar springs into their openings. Slide the side bar into position
Rotate the plug approximately 270 degrees clockwise so the finger pin chambers are visible and the side bar is in a cutout. Having the side bar in a cutout allows the finger pins to be installed.
Once the finger pins are installed and key is inserted, if the plug will rotate a few degrees, requiring the side bar to retract into the plug, it is properly loaded. If not remove the plug from the loading tool being careful not to let the side bar fly. Carefully remove the side bar. The finger pin notches within the side bar slot should be perpendicular to the plug and centered within the slot.
Carefully rotate the plug approximately 270 degrees counterclockwise. The pin tumbler chambers should be vertical. With the key inserted into the plug, load the six pin chambers. For our purpose, the lock cylinder was not master keyed.
The original Schlage Primus patent expired in 2007. New Primus XP patents extend through 2024. To gain additional patent protection, Schlage added a seventh depth finger pin and compatible side...
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