I'm working with a Cemetery's management to open a 1920s mausoleum so cleaning and maintenance can be performed. The key has been lost for many years. We were able to take pictures of the lock from the inside since earlier vandalism had broken part of a stain glass window. The rim lock is brass and measures about 3.75 by 3.75 inches on a side. The center of the Keyhole is about 2.2" from the edge of the door and about 1.125 inches above the bottom of the lock. The lock bolt is about 1.25 inches high and starts just above the keyhole top edge. The lock is about 0.5 inches thick.
From the outside. the nose of the lock is beveled and protrudes 0.125 inches (perpendicular to the door for 0.0625 inches and then beveled. The outside diameter of the nose is 0.75 inches and the inside diameter is 0.5 inches.The keyhole width is in the range of 1.3 to 1.5 mm. The barrel of the lock appears to be recessed by about 0.25 inches from the outer edge of the nose. The bronze door jam seems about 1.5 inches thick. We believe the lock mechanism involves levers.
The locksmith we tried was unable to pick the lock. We found a web posting by steveslockout.com that stated he had opened a similar lock by drilling a hole in just the right spot and then picking the levers. We would like to open the lock without drilling. Can anyone suggest the best tools? One posting suggested using two L shaped wires with a loop at the end for manipulation.