If you understand how a mortise lock works then you could probably visualize a stiff L shaped wire inserted into the bottom of the key way to reach down and throw the bolt.
The issue, as I'm sure you know, that many locks have quite narror keyways, and additionally, many locks with wide keyways have a cam on the back that in some way blocks the use of this kind of tool. Peterson sells the Adams rite latch tool with an interesting shim. If I were a locksmith, I would always try the latch wire, as id be guaranteed to sell the owner at least one new, better lock.
99% of the time its some rel-estate office wanting access and a rekey. These guys are never concerned with the quality of the locks.
i am just looking for quick access and exploring a direction i had not considered until this afternoon when i was servcing some old guys steel storm door.
