Schlage Everest Primus

Schlage Everest Primus
The Everest Primus is a pin-tumbler lock made by Schlage. It uses six pin-tumblers and a sidebar that requires finger pins to be raised and rotated properly. The Everest Primus is functionally identical to the Schlage Primus, but utilizes the keyways of the Schlage Everest.

The Everest Primus has since been superseded by the Schlage Everest 29 SL Primus XP.

Principles of operation

 * See also ASSA Twin Combi

The Everest Primus uses six pin-tumblers and five sidebar finger pins. Unlike its ASSA counterpart, the Everest Primus does not provide any security pins by default. There are 10 depths available for bottom (key) pins. Key pins are numbered 0-9 sized .165" to .300 with a step of .015". There are eight master pins numbered 2-8 sized 0.030" to 0.135" with a step of .015". Driver pins come in three sizes (1-3) from .235" to .165" with a step of .035". These drivers provide pseudo-balanced pin stacks; a 1 driver is used if the size of the key and master pin stack is 0-3, 2 if 4-6, and 3 if 7-9. Any key/master pin stack larger than 9 is invalid (the master pin would not drop down far enough to align at the shear line. In total, there are 1,000,000 (106) theoretical key differs for the pin-tumbler portion of the lock.

The sidebar, located in the 8 o'clock position, is pushed out by two springs. The sidebar bitting on the key raises finger pins which interface with the sidebar. Sidebar finger pins must be raised and rotated properly for the sidebar to retract. When both the sidebar pins and the pin-tumblers are aligned the plug can rotate.