I'm always looking for new challenges and new antique padlocks for my collection. Recently, I bought this Smith & Egge padlock, patented Sept. 4, 1877. This four lever push key padlock is marked "Giant" on the hasp, and I obtained it in the locked position and without a key. This company was known to produce padlocks for postal use, and also was well known for their production of sowing machines. The condition of my lock was excellent. The hasp had slight spring to it in the locked position.The edges of the levers had no sign of wear and they all had strong spring action.
I could find little information about the mechanical workings of this lock. I did find lots of pictures of the Smith & Egge padlocks on Google Images, leading toward the restraints blog. I saw people buying these locks on Ebay in the worst condition, some completely damaged. I concluded that there is a strong desire to learn about the padlock's mechanics.
I knew just a few things about the lock based upon observations and light experimentation. First, the lever stack sweeps counterclockwise, unlike the "Miller" pancake padlocks which sweeps clockwise with the front of the lock as a reference. Second, the levers have a lot of space between them, which might be an advantage for probing material. Third, this lock is really a 4 lever lock with 3 unknown lever depths for purposes of making a key. There will always be one no-cut on the tip of the key. The problem is finding which lever represents the no-cut. Fourth, the levers did not bind while applying tension to the hasp. Fifth, there was no space for the insertion of probe material between the lock body and the hasp. And last, I knew that the levers would lock in place for purposes of making a key once the lock was opened. Most lever locks demonstrate this mechanical behavior.
I went down to a nearby True Value hardware store, and purchased some nicely tempered steel rod with a .063 inch diameter. They sell this stuff in a metal hobby section along with brass and aluminium in a little display case. I cut four equal pieces of the rod to exactly 2 inches long sections. The exact length of 2 inches is not critical, but the four pieces need to be equal length. The lengths were verified with my dial caliper. Lengths were ground down on my bench grinder. The rods were rolled between my fingers to maintain a flat edge.
I took one of the 2 in. wires and began feeling for the movement of the levers. At the time I could feel some slight snagging of the levers at different depths on
some of the levers. I dismissed this clue and tried using wire probes like the ones I use for probing the lever stack of "Miller" pancake padlocks. Unfortunately, the Smith & Egge padlock did not probe out in this manner. I felt that I was at me wits end in an effort to make a key for my lock.
Usually when I get frustrated, I have learned just to walk away from the problem for a while and approach it later with a fresh mind. Later, I began using the 2 inch rods again feeling for the snagging sensation that I observed when I first got the lock. I noticed that with the bottom lever (I call it lever 4) that I could feel a slight snag. I held the rod in position with my fingernail and placed a second rod on the neighboring lever and measured the difference between the two rods using the depth gauge of my dial caliper. The picture below summarizes this.
I made several tests on one lever, making sure that I was getting consistant results. Sometimes the tip of the rod would bind and slip against the lever giving false sensations. I made tests on lever 3 and got snagging of the lever also. Once I did the measuring of the rod for lever 3, I did the math and married the rods of the calculated separation for lever 3 and 4. I taped the two rods together using black electrical tape. I pushed the two rods together in the key hole, and felt them
nest into the lever stack. I knew instantly I was one the right track. While holding the nested pair in the lock, I introduced a third rod on lever 2 and pressed it inward until I got the same nested feeling. This time it was a lot more obvious. While holding all three rods between my fingers, I introduced the fourth rod on lever 1. I slowly pressed it downward, and the lock sprung open. As I predicted the lever stack stayed in a frozen position, making it possible for me to get super accurate reading of the levers for making a key, using the same processes I described in making a key for my pancake lock push key.
I'll post my finished key soon.
