The pin is visible with a mortise or rim cylinder in hand. An access hole reveals the location of the locking pin (see Schlage Primus graphic, p. 36).
Like Sargent 5100 Series cores, a special control key blank is used that is longer than other operating key blanks. When cut to an operating key bitting in the first six positions and a #3 cut in the seventh position, the control key is rotated to the left forcing the locking pin into the body of the core, then the core is pulled out.
By utilizing this strategy, pinning processes are simplified.
Primus features a patented finger-pin and sidebar design providing a "dual-locking" core that is pick-resistant.
Both 23-030 and 20-740 cores cover all popular Schlage keyways.
YALE INTERCHANGEABLE CORES
Yale 1200 Series interchangeable cores are secured into the cylinder housing by way of a locking cam at the back of the lock in the seventh pin position. The cam secures the core into the housing on the left side of the core.
Like other versions of large-format cores, a longer key blank is used for the control. The control is cut similar to the TMK (Top Master Key) and the longer length of the key slides the cam.
When the control key is inserted and rotated to the right, the locking cam enters the core body and the core can be pulled from the housing.
Like other versions of cores, "build-up" or "control" pins are not necessary.
These cores are furnished in either six- or seven-pin configurations. A new feature with these cores is the addition of a spring cover for top loading.
BILOCK INTERCHANGEABLE CORES
Something completely different, not necessarily a "large format" but definitely not a Best-type interchangeable core, is the Bilock QCC Series. The "Quick Change Core" is held into the housing by small ball bearings. The control key is has a set of dimples that allow the ball bearings to recess into the core body when the key is turned to between 30-40 degrees to pull the core out.
The QCC features two independent side-bars controlled by two sets of pins. There are two rows of six pins each. There are four usable depths per chamber.
It is possible to generate 16,777,216 theoretical key combinations. The Bilock QCC Series can be master keyed, having over 500,000 operating keys under the Top Master Key.
Features of the QCC are double-locking protection, simple design, and color-coded keys.
BiLock offers a full range of mortise, rim, key-in-knob, cam, padlock, and utility housings to fit its QCC Series.
All the mentioned lock companies (except BiLock) furnish small-format cores that are compatible with Best/Falcon type "figure-eight" cores. Many of these interchangeable core types offer proprietary patented protection and unique keyways.
The Best/Falcon type cores are not compatible with large existing key systems. This is the forte of the large format and related core system. Each blends in transparently with each company's existing key systems.
It's nice to know that no matter what existing system you use, there is a proprietary large-format interchangeable core that will work with your system. Compatible and cost-effective, they are the way to go when maintaining existing systems.