Problem and Motivation
I've recently started getting a bit more serious about the security of my possessions particularly with regards to firearms. I always keep my firearms secured in a safe when I'm home, but up until recently I have not had a great solution to keeping my firearms locked when I'm transporting them. Typically I'd use an off the shelf master lock and some kind of hard case or the lock that came with the gun itself. This solution works but it has a number of drawbacks. It requires that I carry multiple different keys because rekeying the locks is not possible and each lock uses a different type of key, losing a key or a lock requires replacement of all of the locks, and the locks themselves are not very robust to entry by either destructive (e.g. bolt cutters) or covert (e.g. lock picking) techniques.
Preferably, I would like to purchase a single model of padlock that I can rekey easily and that is reasonably robust against different kinds of attacks. Although I'd like to have super high security locks on everything this is unnecessary because my use case is locking up hard-sided firearms cases and things of that nature. The most secure lock in the entire world won't stop anyone from simply taking the entire case and walking off with it so it makes very little sense to incur the additional expense and logistical hassle of using special high security locks.
Solution
Some time searching on the internet led me to several of Deviant Ollam's videos on YouTube where they recommend the use of Abus 83/45 padlocks for this exact purpose. The Abus 83/45 is a common series of padlocks that seems to have been developed with commercial use in mind. These locks use an interchangeable core which available in several different keyways and replacement parts are widely available as are replacement shackles in multiple different lengths. I originally thought that the ability to change the shackle would not be relevant to me, but I later discovered that the standard 1" shackle that ships with the lock is not long enough to properly fit thru a Pelican Vault padlock hasp and that the 2" shackle is necessary instead. Being able to change the shackle means that I didn't have to purchase entirely new padlocks.
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The Plan
The plan was thus:
- Pick a keyway to use and order the necessary padlocks, pins, and pinning tools to rekey it.
- Decide on a key bitting to use and order keys cut to this bitting.
- Rekey and test all of the locks.
- Put the locks into service.
Before beginning this project I had a basic an understanding of locks and how they work - largely from watching Deviant Ollam's numerous videos on the subject - I had never actually taken one apart or rekeyed one. Figuring out how to do this properly was a fun learning exercise.
Keyways, Padlocks, Pins, and Tools
I decided on the Schlage C keyway because it is a common keyway and a lot of reference is available for it online. The other options such as Kwikset, Best, or SFIC all would have worked just fine but in the end I just had to pick one. Had I wanted to key my locks to match my house key I would have chosen Kwikset but I decided against doing this because it is a generally bad security practice to key a padlock to match your landlord's keys. I also did not want a lost or stolen key or lock to compromise my house in addition to my padlocks.
The 83/45 Schlage by default comes configured with 5 pins installed and a small bag containing the components necessary to install a 6th pin. When configured for 5 pins the corresponding key is a Schlage SC1. When configured with 6 pins the corresponding key is a Schlage SC4. The only difference between the SC1 and SC4 is that the SC4 is longer to accommodate the 6th pin but they both fit into the Schlage C keyway.
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| On left: a spool driver pin, spring, and cap plate necessary to populate the 6th chamber of the lock core. On right: an 83/45 lock core with an empty 6th chamber. |
I decided that I would use all 6 pins because I had no reason to do otherwise and I wanted to obtain the most security that I could out of these locks. Leaving pins out simply did not make any sense for my application, but if you were keying padlocks to an existing SC1 5-pin key then this may not be an option for you.
In addition to the padlocks themselves I needed to obtain pins, pinning tweezers, a pinning tray, and a Phillips screwdriver. I already had a Phillips screwdriver and I used my 3D printer to print out a pinning tray from one of the many repositories of 3D printable files on the internet. The pins, padlocks, and pinning tweezers I purchased from CLK Supplies online.
Key Bitting and Ordering Keys
This part is where most of my learning occurred because this step is where the concepts involved in rekeying a lock actually have to be reduced to practice. Fortunately, we live in Calendar Year and the internet contains a wealth of information to assist in this process. A quick internet search returned this article
from Locksmith Ledger which I found to be enormously helpful. The
article is about master keying but the entirety of its contents discuss
how to properly configure the pins within a lock in order to ensure that
the lock functions properly and falls within the standards of the lock.
Helpfully, the article uses Schlage locks for all of the examples and
several charts and tables relevant to Schlage locks are provided. I read and reread the article several times during this process in order to make sure I had a good grasp of what I was doing.
The bitting of a key is the height to which each position of the key is cut. The height of the pins within a lock must correspond to the height of the cuts on its key in order for the key to open the lock. When selecting the bitting of a key some common sense should be applied (e.g. the bitting should not all be the same number like 2-2-2-2-2-2, should not follow a pattern like 1-2-3-4-5-6, etc), and the Maximum Adjacent Cut Specification (MACS) must also be followed. MACS is the maximum difference in height any two adjacent pins can be while still allowing the lock to function properly. Exceeding MACS can result in keys which are impossible to cut or that jam up inside the lock because the pins are subjected to excess forces. For Schlage, MACS is 7 which means that any two pins must be within 7 positions of each other. (Note, I have seen some sources which state that Schlage MACS is 6. I stayed within 6 when pinning my locks just to be safe.)
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| My key, marked "A" on the bow for identification. The bitting has been redacted for privacy. |
I selected a bitting for a 6-pin SC4 keyway and found a locksmith online that will cut keys to a bitting code. When ordering keys cut to a bitting code make sure that the bitting sequence is specified in the correct order. For Schlage, the bitting code is specified from bow (the part where you grip the key to turn it in the lock) to tip but other types of keys may be backwards. I ordered 4 keys to make sure that I had sufficient spare keys. I also
asked the locksmith to mark all of my keys by stamping a letter onto the
bow of the key so that I could identify them in the future.
Rekeying the Locks
There are plenty of videos on YouTube that show how to rekey an 83/45 so I won't cover every detail here but the process is quite simple. First, open the lock and use a Phillips screwdriver to remove the screw under the shackle. This will allow the lock core and the key-retaining "Z-bar" to fall free. The 83/45 has a pinning "window" in the cylinder that eliminates the need to remove the entire plug to change the key pins. By inserting the key and turning to the left, the key pins align with a small window in the core. There is a small detent on the core that must be depressed before the key will turn to the left in order to prevent this from happening during normal operation of the lock.
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| Abus 83/45 padlock partially disassembled, pins and lock parts in a pinning tray, and a screwdriver. The pins to be installed are pixelated for security. |
Once the key pins are exposed, removing them is a simple matter of turning the core upside down and dumping the pins out. The new pins are installed into the core one at a time in their appropriate positions using pinning tweezers. Before closing the lock, I made sure to check my work by inserting my key and making sure that all of the key pins aligned with the shear line of the lock. If any pins are raised above the shear line, the lock will not close. If any pins remain below the shear line then the lock will close but the key will not open it again and the only methods to open the lock at that point would be either to pick it open or use destructive methods such as a drill.
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| New key pins installed into the lock. With the key inserted, all pins are raised exactly to the shear line. |
Once the new pins are installed properly installing the core back into the lock involves putting the Z-bar back in place, putting the core back into the body of the lock, and reinstalling the screw that was removed previously. At that point, the lock is functional and ready for use.
Next Steps and Unanswered Questions
Master Keying
My future plans for my locks involve setting up a very limited master key system. I'd like to configure the system such that I have locks for firearms and locks for things that need to be secure but that aren't firearms. This way I can have one key that will open all locks and another key that will only open locks that aren't securing firearms.
A Note about Driver Pins
One hiccup I had during this whole process was the matter of the driver pins (also called top pins). The 83/45 ships with 0-cut key pins in all chambers and a spool driver pin in each chamber. According to the Locksmith Ledger article mentioned previously, the height of each driver pin should be set according to the length of the corresponding key pin. This is because a long key pin with a long driver pin may combine to be so long that they crush the spring when a key is inserted that lifts the pin to a high position. Using shorter driver pins with longer key pins and vice-versa prevents this problem. However, I'm not sure if this guidance applies to every lock or only to some locks.
In this case, I made the assumption that this lock is designed to tolerate any size key pin in any chamber because of how the lock is configured. My assumption is that Abus would not provide a pinning window on this lock if installing longer pins would cause excessive compression of the driver springs because that would require an end user to replace all the driver pins by removing the plug and that would render the pinning window useless. Further, although I could remove the existing driver pins and replace them I was reluctant to do this because the 83/45 has spool security driver pins in all 6 chambers and I would have to replace them with standard drivers.
So far, my locks function quite well and I have not seen any reason to believe that my assumption is wrong. However, someone more knowledgeable might see problems that I am not aware of.
