"The new ML System is a patent-pending Key Control product. It is not high security and does not offer increased pick or drill resistance." This is the opening sentence from a September 2003 update of the Master Lock Technical Manual.
At the heart of the ML System is a new keyway plus a lock plug that contains holes drilled at approximately right angles to the vertical keyway. Two rounded grooves are milled inside the cylinder housing, one groove on each side of the keyway. Both grooves are milled along the entire length of the housing. Two 3/32" ball bearings are inserted into each of the drilled holes in the lock plug during final assembly.
As an ML key blank is inserted into the lock plug, the sets of ball bearings are moved outward into the grooves in the cylinder wall. The ball bearings form a second locking system and the plug is prevented from turning even if the key cuts correctly align the pin tumblers at the shearline. The ML System requires dimple cuts to be made at the same location as the ball bearings. When an ML key with proper tumbler and dimple cuts is inserted, the ball bearings can freely move into the dimpled areas as the key begins to be turned, and the lock can be opened.
Master Lock refers to each set of dimple positions as a "virtual keyway section." Reportedly about 70 different virtual keyways can be made.
ML System cylinders are available in both a four-pin and six-pin version. The shorter four-pin version will obviously have less dimple positions and less virtual keyways. ML System locks have eight possible depth increments which can produce 4096 possible code combinations for four-pin locks and 262,144 possible combinations for six-pin locks. Multiply possible combinations by the amount of virtual keyways and totals are quite staggering when compared to a standard key system.
Application for ML patents was made in 2003. Government regulations now allow an approved patent to be in force for 20 years, starting when the patent application was submitted. When accepted, the ML patent should be in force until 2023.
Master Lock has established the following four levels of key control.
Level 1 is for ML locks that are available from distributors. Locksmiths can purchase Master ML System lock products as needed. Any additional duplicate keys required in the future would be ordered from the distributor. Uncut key blanks are not available. A contractual agreement is not required.
Level 2 is designed for retail locksmiths. The locksmith is assigned one of the virtual keyways. The locksmith can order uncut key blanks with that specific virtual keyway, which are automatically stamped with a special six-character ID number. A contractual agreement and an initial amount of purchased product are required.
Level 3 is designed for institutions and commercial buildings with a locksmith on staff. The customer is assigned one of the virtual keyways. The customer can order uncut key blanks with that specific virtual keyway which are automatically stamped with a special six-character ID number. A contractual agreement and an initial amount of purchased product are required.
Level 4 is factory controlled. Key blanks are not available. Key code information is kept confidential by the manufacturer. All future additions of duplicate keys or lock products will be by factory order.
SERVICING THE ML CYLINDER
Depth and space dimensions are identical to the present 6000K and 7000K keyways.
Depths: 0.) 285 1.) 269 2.) 254 3.) 238 4.) 223 5.) 207 6.) 192 7.) 176