Tue Apr 17, 2018 8:23 am by rphillips52
When SLS started (in the 1970's, from memory), they did not make their own locks, but bought in from, (again from memory), Yale. Tann had been making many locks of this basic construction — two plates with no case sides — for various purposes, including secure lockers etc.The British War Office/MoD used some, eg.
Later, SLS and SMP had their own designs. These locks, with 7-9 levers, are sufficiently challenging for inexperienced safebreakers with little equipment or skill, and identifying the many variants through the keyhole is also a challenge for drilling quickly. Burglars have to work against the clock, and possibly a silent alarm also ... .
As security requirements tightened, many basic safe [key] locks came to be used on a multitude of secure cabinets, for drugs, guns, school and club trophies, etc., etc..
Key locks are quick and easy to use, strong, reliable, and with little scope for user error. No chance of the combination being written on the side of the safe. Key-retaining versions are also available, and these days there are also inexpensive change-key locks. Whatever the appearance presented by youtube, picking is not trivial, and a range of sizes of kit is needed to cope with the variety of locks which might be encountered.