There are two different large format interchangeable cores from Medeco: Series 31 and 32.
The Series 31 is designed to fit mortise, rim, key-in-knob locks that have been prepped to accept Yale interchangeable cores. Like a Yale, the core is held into the cylinder is held into the housing by a cam at the back of the core. The cam protrudes on the left side of the core and is pulled back when a special control key blank is utilized.
The Series 31 control key blank is longer than the operating key blank. When cut the same as a operating key, the added length and a twist to the right, slides the cam into the core, the core is then removed. Securing the core into the housing in this fashion eliminates the need for "build-up" or "control" pins. This simplifies the keying process.
Series 31 cores are available in six-pin only.
There is a high-level of drill and pick resistance but not to the level of UL437.
The Series 32 interchangeable cores are locked into the sleeve with a control lug positioned in the middle of the core (third and fourth chambers). The control lug protrudes on the right side of the core.
Like the series 31, no "build-up" or "control" pins are needed. To remove the core, a key is cut similar to an operating key with the exception that the third and fourth chambers are cut three increments shallower. The key is inserted and turned slightly to the left, which rotates the control lug into the core. The core is then pulled out.
If the respective operating cuts in the third and fourth positions are 4 and 5, then the control cuts will be 1 and 2.
Care need to be taken when series 32 cores are integrated into a master key system. Because control keys are required to be three increments shallower in the third and fourth positions, this parameter needs to be worked into the system before it is initiated.
Series 32 cores are UL437 listed because of their pick and drill resistance and strength against other forms of forced attack. They are available in both six- and seven-pin configurations.
Both series utilize a double-locking principle providing pick resistance and benefit from utility patents that provide protection from unauthorized duplication of keys.
SARGENT REMOVABLE CORES
The "Old-Style" 5100 Series removable core was the original removable core supported by Sargent. The 5100 Series is based on using a seventh position on the control key and in the core. All other operating keys are cut on six-pin length key blanks. When the longer key blank is cut to the bitting of an operating key and is cut to a #3 depth in the seventh position, it will slide back the cam and allow the core to be extracted from the housing.
A five-pin version is available.
It is only available for mortise and rim cylinders and is currently furnished only for additions to existing key systems.
The mainstay of removable cores for Sargent is based on the 6300 Series core. The control lug is on the right side of the core and is pulled into the core when the control key is inserted and rotated to the left.
The control key bittings match the TMK (Top Master Key) in positions 1,2,5 and 6. The control key bittings in the 3 and 4 positions are selected from a key-bitting array.
The stack values in non-control chambers (chambers 1, 2, 5 and 6) equal 15. Three pins are stacked in these chambers the bottom, master, and driver. To compute the driver, subtract out the total of the bottom and master pins from 15.
The stack value in the control chambers (chambers 3 and 4) equal 20. Four pins are stacked in these chambers the bottom, master, control, and driver. To determine the control pin, subtract the total of the bottom and master pins from the total of the control key bit and 8. Determine the driver by subtracting the total of the bottom, master, and control pin from 20.