Schlage Primus

=Schlage Primus=

The Primus (or Classic Primus, Primus XP) is a UL 437 rated 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 Primus is functionally identical to the ASSA Twin Combi lock, but it does not include as many anti-lockpicking and key control mechanisms. The patent protection on Primus keys ended in 2007.

The Primus is an updated version of the Schlage Everest. The Schlage Everest Primus is an alternate version of the Primus that enhances key control capabilities.

Principles of operation

 * See also ASSA Twin Combi

The Primus uses six pin-tumblers and fix sidebar finger pins. Unlike its ASSA counterpart, the 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-tumbler are aligned the plug can rotate.

Notes
 * The Primus is available in rated and non-rated cylinders. Non-rated cylinders do not include hardened anti-drill protections.

Key security levels
The Primus offers a variety of key security levels:


 * Level 1 - Commercially Exclusive
 * Distributors sell to end users via commercial locksmiths. All Level 1 keys have the same sidebar bitting code.


 * Level 1+ - Wholesaler/Locksmith Exclusive
 * Locksmiths resell exclusive wholesaler sidebar bittings. Keys are stamped with unique locksmith ID numbers.


 * Level 2 - Contract Hardware Dealer Exclusive
 * Exclusivity limited to contract hardware dealers who sell directly to end users.


 * Level 3 - End User Exclusive
 * Exclusivity based on random assignment or the first 2 digits of a zip code.


 * Level 4 - End User Exclusive
 * Exclusivity based on time zone or nation.

Disassembly instructions
The Schlage Primus is disassembled in the same way as a traditional pin-tumbler cylinder. Care is taken to account for the sidebar and finger pins. Finger pins are spring biased outwards when the plug is exposed without a key inserted.

Vulnerabilities

 * Lockpicking
 * Key bumping
 * Impressioning
 * Decoding

Notes
 * Key bumping is possible only with a bump key that has the correct sidebar code.

Gallery
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