How to Rekey a Lock: Mastering the Art of Security Without Replacement
Somewhere between the satisfying click of a well-oiled lock and the frustration of fumbling with outdated keys lies a skill that most homeowners never realize they possess. Lock rekeying sits in that peculiar space where DIY enthusiasm meets genuine security concerns—a realm where a few dollars in pins can save hundreds in locksmith fees, and where understanding the mechanics of your front door becomes oddly empowering.
I stumbled into lock rekeying the way most people do: through necessity mixed with stubbornness. After my third tenant moved out, leaving me with yet another set of keys floating somewhere in the universe, I decided enough was enough. The locksmith wanted $75 per lock. My house had eight locks. You do the math. That's when I discovered that the mysterious art of rekeying wasn't so mysterious after all.
The Anatomy of Your Average Lock
Before diving into the actual rekeying process, let's talk about what's happening inside that brass cylinder every time you slide your key in. Pin tumbler locks—which make up about 90% of residential locks in North America—operate on a beautifully simple principle that hasn't changed much since Linus Yale Jr. perfected it in the 1860s.
Inside the lock cylinder, you'll find a series of spring-loaded pins, typically five or six sets. Each set consists of a driver pin (top) and a key pin (bottom). When you insert the correct key, it pushes these pins to exactly the right height, creating what locksmiths call the "shear line"—that magical alignment where the cylinder can rotate freely.
The wrong key? Those pins sit at the wrong heights, blocking rotation like tiny metal bouncers refusing entry to an exclusive club.
Why Rekey Instead of Replace?
Here's something the big-box hardware stores won't tell you: that $45 deadbolt you're eyeing is probably unnecessary. Unless your lock is damaged, worn out, or you're upgrading to a different style, rekeying accomplishes the same security goal for a fraction of the cost.
I've rekeyed locks that were installed during the Carter administration and they work better than some modern locks fresh from the factory. There's something to be said for the build quality of older hardware—those hefty Schlage and Kwikset locks from the '70s and '80s were built like tanks.
Rekeying makes sense in several scenarios:
- Moving into a new home (who knows how many copies of those keys exist?)
- After a roommate or tenant moves out
- Lost keys that might compromise security
- Consolidating multiple locks to work with one key
- Following a break-in or security concern
Tools of the Trade
The beauty of rekeying lies in its minimal tool requirements. You don't need a workshop full of specialized equipment. Here's what actually matters:
A rekeying kit specific to your lock brand runs about $10-15 and includes various pins, springs, and the essential follower tool. That follower—a simple plastic cylinder—is the unsung hero of the operation. Try rekeying without one and you'll understand why locksmiths guard theirs like precious gems.
You'll also need:
- A pair of needle-nose pliers (the smaller, the better)
- Tweezers for handling tiny pins
- A small screwdriver
- Good lighting (seriously, those pins are minuscule)
- Patience (not sold in stores, unfortunately)
Some folks swear by magnetic pin trays. After chasing pins across my garage floor more times than I care to admit, I'm inclined to agree.
The Rekeying Process: Where Theory Meets Reality
Every lock brand has its quirks, but the general process remains consistent. I'll walk through the most common scenario—rekeying a Kwikset or Schlage pin tumbler lock.
First, remove the lock from the door. This isn't technically necessary for all locks, but trust me, working at a comfortable height beats crouching by a door any day. The cylinder typically comes out after removing two long screws from the interior side.
Insert your current key and turn it to the 3 o'clock or 9 o'clock position—this aligns those pins at the shear line. Now comes the moment of truth: removing the cylinder plug. On Kwiksets, you'll push out the cylinder retainer clip (that C-shaped piece of metal). Schlages use a removable cap that unscrews.
Here's where that follower tool earns its keep. As you slowly pull out the cylinder plug with the key still inserted, slide the follower in behind it. This keeps the driver pins and springs from launching across your workspace like tiny projectiles. The first time I skipped this step, I spent twenty minutes hunting for springs under my workbench. Lesson learned.
With the plug removed, you'll see the key pins sitting in their chambers. These need to come out. Dump them into your magnetic tray (or, if you're like me on my first attempt, watch them scatter across your work surface).
Now for the fun part: selecting new pins. Your new key determines which pins go where. Most rekeying kits include a gauge that shows which pin corresponds to each cut depth on your key. It's like a very boring puzzle where all the pieces look nearly identical.
Insert the new key into the plug and place the appropriate pins in each chamber. When done correctly, the tops of all pins should sit flush with the plug surface. Too high? The cylinder won't slide back in. Too low? The lock won't work properly.
Reversing the disassembly process requires steady hands. Keep that follower in place as you slide the plug back in, then remove it once everything's aligned. Replace the retainer clip or end cap, and you've successfully rekeyed your first lock.
Common Pitfalls and How to Avoid Them
Let me save you some frustration by sharing the mistakes I've made so others don't have to.
Mixing up pin sizes is surprisingly easy when you're dealing with differences measured in thousandths of an inch. I once spent thirty minutes troubleshooting a lock that wouldn't work, only to discover I'd swapped two pins that looked identical to my aging eyes. Now I double-check with the gauge before inserting each pin.
Master keying—creating a lock that works with two different keys—sounds simple in theory. In practice, it's a recipe for security vulnerabilities and mechanical problems. Those extra wafer pins create more potential shear lines, making the lock easier to pick. Unless you're managing a commercial property with a genuine need for hierarchical access, skip the master keying.
Spring tension matters more than you'd think. Old springs lose their bounce, causing sluggish lock operation. While you've got the lock apart, consider replacing those springs. The fifty cents spent on new springs beats the annoyance of a sticky lock.
The Professional Perspective
After rekeying dozens of locks over the years, I've developed enormous respect for professional locksmiths. Yes, the basic process is straightforward, but there's an art to doing it quickly and correctly. A good locksmith can rekey a lock in under five minutes. My first attempt took an hour and included two complete do-overs.
Professional locksmiths also handle the oddball situations—high-security locks with sidebar mechanisms, European profile cylinders, and antique mortise locks that predate standardization. They've got the specialized tools and, more importantly, the experience to tackle these challenges.
Security Considerations Beyond Rekeying
While we're inside your locks, let's talk about actual security. Rekeying only addresses the "who has keys" problem. It doesn't fix fundamental vulnerabilities in your lock hardware.
Those generic locks from the hardware store? They're using what the industry calls "builder grade" components—adequate for keeping honest people honest, but not much more. The pin stacks are brass, which wears quickly. The tolerances are loose, making picking easier. The cylinders lack hardened inserts to resist drilling.
If you're genuinely concerned about security, rekeying should be part of a broader strategy. Consider upgrading to locks with security pins (spools, serrated, or mushroom pins that resist picking), hardened cylinders, and pick-resistant keyways. Brands like Medeco, Mul-T-Lock, and ASSA make locks that would frustrate all but the most determined intruders.
But here's a reality check: most burglars don't pick locks. They kick doors, break windows, or find unlocked entries. A properly installed deadbolt with a reinforced strike plate and 3-inch screws into the door frame does more for security than the fanciest lock cylinder.
The Economics of DIY Rekeying
Let's talk money, because that's often what drives people to learn this skill. Professional rekeying typically runs $20-40 per lock, plus a service call fee. For a typical home with 4-6 locks, you're looking at $150-300.
A rekeying kit costs $10-15 and handles multiple locks. Even if you value your time at a reasonable hourly rate, the math favors DIY after just two or three locks. Plus, you gain a skill that pays dividends every time you need it.
I've probably saved over $1,000 in locksmith fees over the years, not counting the times I've helped neighbors and family members. There's also the convenience factor—no waiting for appointments or taking time off work.
When to Call a Professional
Despite my DIY enthusiasm, I'm not too proud to admit when I'm out of my depth. High-security locks, electronic locks, and anything involving safe mechanisms get the professional treatment. Same goes for automotive locks—modern car keys with transponder chips involve programming that goes well beyond mechanical rekeying.
Antique locks deserve special consideration. That beautiful mortise lock from 1920 might be worth preserving in its original state. A ham-fisted rekeying attempt could damage irreplaceable components. Sometimes, the smart money is on professional expertise.
Final Thoughts on the Rekeying Journey
Learning to rekey locks changed my relationship with the mechanical world around me. It's one of those skills that seems impossibly complex until you try it, then becomes almost meditative in its precision.
There's something deeply satisfying about understanding how things work, about taking control of your home's security without depending on outside help. Every time I slide a newly rekeyed key into a lock and feel that smooth rotation, I'm reminded that competence in small things builds confidence in larger ones.
The locks on your doors are probably the most frequently used mechanical devices in your home. Understanding how they work, how to maintain them, and yes, how to rekey them, puts you in control of your security in a very literal way. It's a skill worth having, even if you only use it once.
So next time you're faced with a lock that needs new keys, consider taking matters into your own hands. With patience, the right tools, and perhaps a spare lock to practice on, you might discover that the mysterious art of rekeying isn't so mysterious after all. Just remember to keep track of those tiny pins—they have a tendency to vanish into the quantum realm when dropped.
Authoritative Sources:
Phillips, Bill. The Complete Book of Locks and Locksmithing. 7th ed., McGraw-Hill Education, 2016.
"Pin Tumbler Lock." Encyclopedia Britannica, Encyclopedia Britannica, Inc., 2023, www.britannica.com/technology/pin-tumbler-lock.
National Locksmith Association. Introduction to Locksmithing. National Locksmith Association Publications, 2019.
U.S. Department of Justice. "Residential Security: A Guide for Homeowners." Office of Community Oriented Policing Services, 2020, cops.usdoj.gov/residential-security.
Yale, Linus Jr. "Improvement in Locks." U.S. Patent 48,475, filed January 29, 1865, and issued June 27, 1865. United States Patent and Trademark Office, www.uspto.gov.