One of the most interesting places I’ve lived with my family is a late 19thcentury farmhouse in Ann Arbor. The house is huge, maybe 4000 sq. ft, and welived in an apartment occupying the entire first floor. The most notable,permanent fixture in the apartment is this massive safe:
Our landlord mentioned that it was so big and heavy, the safe was wheeled inwhile the house was still under construction and the building was completedaround it. The safe was locked, and she didn’t have the combination.
Interiors, Herring-Hall-Marvin Safe Co., Offices, Safes, Filing Cabinets. The Herring-Hall-Marvin Safe Co. Metal furniture installation at the Grand Central Depot offices. The only marks I can see on the safe are the name of the company (Herring Hall Marvin Safe Co). And then under it i can see some numbers beginning with 194. I don't know if this is the beginning of a date from the 1940's or a part of a serial number or what? Any information you can provide would be great! Virtual all safes are either three or (less commonly) four numbers. Obviously, each of those numbers may be more than one digit. If it's three then the most common sequence would be: Turn the dial left 4 times to the first number, right 3 times to the next, left 2 times to the last, then right until the dial stops, at which point the handle.
Mseifert wrote: It is indeed a Herring Hall Marvin Safe. Cant read the serial number clearly but based on its placement on the ball of the handle. It was made sometime between 1892 to 1930. Based on the serial number someone might be able to tell you when it was made. Virtual all safes are either three or (less commonly) four numbers. Obviously, each of those numbers may be more than one digit. If it's three then the most common sequence would be: Turn the dial left 4 times to the first number, right 3 times to the next, left 2 times to the last, then right until the dial stops, at which point the handle.
While we lived there, we occasionally joked about ways to crack the safe. Thetwo leading ideas were:
- Use an Arduino and a few stepper motors to iterate over every possiblecombination automatically, and just let it run while we lived there.
- Host the equivalent of a rent party and have guests pitch in to hire someoneto drill into the safe.
The mechanics of the automatic safe cracker eluded me, being more softwareand “light duty” hardware inclined, and some online research led me to believethat drilling would be very destructive and might not work. We let the ideas go,and just lived with the massive block of metal in our peripheral vision. Thecats stared at it while in the litter box.
Two weeks from the end of our lease, I found myself sitting in front of thesafe, feeling terrible about leaving such a challenge behind.
I read up on the basic safecrackingand learned there are more intelligent, statistical methods to find thecombination than brute force. This seemed like it might be a good activity whennot packing moving boxes.
The only marking on the safe were the company that manufactured or distributedit - Hall’s Safe & Lock Company. I found a post in an antiquesforum describingthe possible types of locks and how they might be unlocked. I hadn’t eventhought of how it might be challenging to figure out the unlocking process evenif I had the code.
Again, I felt like giving up, but I thought of how this might related tocracking a computer password in the 21st century. The most efficient way isoften social engineering, especially if you can find the password on a stickynote near the computer in question. Whomever last opened this safe surely wrotethe combination down somewhere. Suddenly, this caught my eye, in the doorjam ofan adjacent utility closet:
Why is there a small piece of masking tape in the door jam? I looked closer andnoticed it had very faint markings. I carefully removed it from the wall and wasable to read it under the right lighting conditions, mostly.
There’s still a lot of mystery. What does p with bar over it mean? Isthe last number 60 or 69? How do I actually use these numbers with the safe’scontrols to open it?
Spinning the Dial
I was able to solve the last question thanks to the digitized Duke UniversityArchive and this originalinstruction sheet for a Hall’ssafe.
By seeing the description of how to unlock the safe with some sample numbers, Icould decode the notation on the masking tape:
The p with a bar over it turned out to be from the Latin “post”, meaning after.The last person to unlock the safe may have been a doctor, because I found thisis a common abbreviation in medicine (or maybe a physicist, as a leared p-baralso stands for antiprotons).
The final procedure to unlock the safe was:
- Spin 3 times left to 67.
- Spin 2 times right to 79.
- Spin 1 time left to 115.
- Turn directly to 60 without spinning around.
It took only a few attempts once I found this formula, and finally the handleturned:
Herring Hall Marvin Safe Company Serial Numbers Number
Immediately, I realized that trying to drill into the door would have beenfutile due to the depth:
Even worse, a brute force physical approach would have wrecked the decoration onthe interior door:
The suspense was high. The whole point of cracking a safe is to get what’sinside:
Alas, it was empty except for a 20-year old thermostat and an old German stamp:
Herring Hall Marvin Model Numbers
The stamp is from approximately 1922, German Deutsches Reich 100000 Mark PostageStamp. It’s available for a few dollars online, so while this exercise didn’tend in financial riches, I’m really glad to say I didn’t leave the house withthe safe un-cracked.