Rekeying Kit
Quick answer: A rekeying kit is a packaged set of pins, springs, tools, and keys used to change the internal pin combination of a pin-tumbler lock cylinder, making old keys inoperable while creating a new working key without replacing the entire lockset. For professional rekeying results, Low Rate Locksmith offers licensed, bonded, 24/7 mobile locksmith services to handle the process quickly and correctly.
What Is a Rekeying Kit
Plain Language Definition
A rekeying kit is a collection of small, precisely machined components and the tools required to install them inside a pin-tumbler lock cylinder. At the core of any rekey kit are key pins — also called bottom pins — which are the variable-height pins that contact the cut profile of a key. When a specific combination of key pins is seated correctly against a corresponding set of driver pins and springs, the shear line aligns and the cylinder rotates. To change the combination, every key pin must be removed and replaced with a new set whose heights match the cut depths of the new key. A rekeying kit supplies the range of pin sizes needed to accomplish this.
A standard complete rekeying kit typically contains the following components:
- Key pins (bottom pins): Available in multiple heights, usually designated by number (0 through 9 for most American-standard systems). The kit must include every size required for the lock brand being serviced.
- Driver pins (top pins): These sit above the key pins and are pushed down by springs. Most residential pin-tumbler locks use uniform-height driver pins within a given brand, though security pins — spool pins, serrated pins, mushroom pins — appear in higher-grade cylinders and require a specialized pin kit.
- Springs: Coil springs that press the driver pins downward. Springs weaken over time and are often replaced during a professional rekey.
- Plug follower: A cylindrical tool the same diameter as the lock plug. It holds the driver pins and springs in the shell while the plug is removed, preventing the spring-loaded pins from scattering.
- Key decoder or caliper: Used to read the cut depths of the new key so the correct key pin sizes can be selected before the cylinder is reassembled.
- Pinning tray or loading tool: A channeled block that holds pins in sequence during the rekeying process, reducing the risk of mixing sizes or losing parts.
- Plug removal tool or turnbolt extractor: Removes the retaining clip or ring that secures the plug inside the lock body.
- Instruction guide: Most consumer DIY rekey kits include brand-specific instructions with cut-depth charts; professional rekey kit configurations rely on the technician’s training rather than printed guides.
A lock rekeying set intended for professional use is distinguished by breadth: it carries the full pin range for multiple brands, security pin varieties, a selection of follower sizes, and precision tools that are durable enough for daily use across dozens of locks. A DIY rekey kit, by contrast, is typically sized for a single brand, contains a limited pin inventory, and includes lighter-duty tools adequate for occasional home use.
Where It Is Used
A rekeying kit is used wherever pin-tumbler locks are installed and key control needs to change without hardware replacement. The most common settings include:
Residential property transitions. When a homeowner moves into a previously owned or rented property, rekeying every exterior lock is the single most cost-effective way to establish exclusive key control. A rekey kit — or a locksmith carrying one — makes this possible in a single visit without touching the deadbolts, knobsets, or door hardware that is already installed.
Multi-unit rental properties. Landlords and property managers often use a professional rekey kit system on a scheduled basis between tenancies. Because pin-tumbler cylinders can be rekeyed dozens of times before wear necessitates cylinder replacement, rekeying is considerably less expensive than hardware cycling.
Commercial access control. Offices, retail spaces, and light industrial facilities frequently rekey after employee terminations, contractor engagements, or security audits. A complete rekeying kit carried by a commercial locksmith often includes Medeco lock brand, BEST, Falcon, or other commercial-grade pin configurations not found in consumer DIY kits.
Master key systems. Building managers who operate master key hierarchies use a pin kit to install both key pins and master wafers — thin spacer pins that create a secondary shear line. Constructing or modifying a master key system demands a professional rekey kit with the full range of master wafer sizes and a working knowledge of key bitting charts.
Post-lost-key incidents. Any time a key is lost, stolen, or copied without authorization, rekeying is the appropriate response. A rekey kit allows the lock to be reconfigured to a new key in minutes, eliminating the need to replace the lockset entirely.
Smart lock and keypad retrofits. Some smart-lock installations include a rekeying kit so the accompanying traditional cylinder can be matched to the home’s existing key. Kwikset’s SmartKey system, for example, ships with its own proprietary rekey kit designed for in-lock rekeying without disassembly.
Security and Service Considerations
Common Problems
Rekeying a lock with a rekey kit seems straightforward, but the small scale of pin-tumbler components and the precision required for correct function mean that errors occur more often than most people anticipate. The following problems appear regularly in both DIY rekeying attempts and in work performed by undertrained technicians.
Pin mixing and size errors. Key pins are distinguished by height differences as small as 0.025 inches (approximately 0.6 mm) between adjacent sizes. Mixing two adjacent sizes — a common outcome when pins are poured out of a disorganized rekeying kit onto a work surface — produces a lock that binds on the correct key, accepts keys it should reject, or fails to rotate at all. A quality rekeying kit includes a numbered pinning tray precisely to prevent this; skipping this step is the leading cause of post-rekey lock failures.
Spring omission or wrong-rate springs. Springs are easy to lose because they are tiny and under tension. Some DIY rekey kit packages contain only enough springs for a single lock, meaning that if one is launched across a room, the installer may seat a pin without a spring — creating a permanently set shear line in one chamber and making the lock pickable with minimal effort. Professional locksmiths carry bulk spring stock in a complete rekeying kit as a standard precaution.
Plug follower misuse. If the plug follower is removed before all driver pins are re-seated, or if it is the wrong diameter for the shell, the driver pins and springs can drop into the lock body. Recovering scattered pins from inside a lock body sometimes requires full disassembly and, in worst cases, replacement of the lock body or the entire lockset. A universal rekey kit that includes multiple follower diameters reduces this risk for technicians working across brands.
Security pin substitution errors. Higher-security locks use spool or serrated driver pins that create false sets during picking attempts. When a rekey kit contains only standard driver pins, reinstalling them in a cylinder originally equipped with security pins degrades the lock’s pick resistance. Conversely, installing a security pin type incompatible with the cylinder’s tolerances can cause binding on the correct key. Neither outcome is acceptable in a professionally completed rekey.
Wrong pin kit for the brand or series. Kwikset and Schlage use different pin sizes, different follower diameters, and different keyway profiles. A rekey kit for Kwikset will not produce correct results in a Schlage cylinder, even if the components appear similar. Generic or universal rekey kit products must be verified against the specific lock series being serviced, not assumed to be interchangeable.
Damaged plug or shell threads. Some lock designs use a threaded retaining ring to secure the plug. If the plug follower or removal tool slips, the ring or the plug’s retaining groove can be damaged, making it impossible to reassemble the cylinder correctly. This type of damage is more common with low-quality tools included in budget DIY rekey kits.
Incomplete key verification. After rekeying is complete, the technician must verify that the new key operates the lock smoothly through the full rotation and that all previous keys are positively rejected. Skipping this step — common in rushed DIY attempts — leaves open the possibility that pin sizing errors create intermittent operation, which may not surface until the lock is under field conditions.
Related Locksmith Work
A rekeying kit is the central tool of the rekeying process, but it connects to a broader range of professional locksmith work that addresses adjacent security and access needs.
Cylinder replacement. When a lock cylinder is too worn, damaged, or of insufficient grade to justify rekeying, the correct action is cylinder replacement rather than using a rekey kit on a degraded component. A locksmith carrying a complete rekeying kit will typically also carry common cylinder sizes to allow on-site swaps.
Master key system construction. Building a master key system goes beyond single-cylinder rekeying and requires a pin kit that includes master wafers, comprehensive bitting charts, and a systematic approach to key control documentation. Professional locksmiths who specialize in master key systems treat the rekey kit as one component of a larger toolkit that includes key control software and restricted-keyway hardware.
Lock repair and maintenance. A rekeying kit session often reveals worn springs, corroded pins, or a damaged keyway — findings that require repair or parts beyond what the kit contains. Lubricating the cylinder and inspecting the plug and shell for wear are standard steps that accompany professional rekeying.
Primary entry-door lock upgrades. When rekeying reveals that the existing hardware is of insufficient grade — a common finding on older residential deadbolts with minimal pin depth — a locksmith may recommend upgrading the primary entry-door lock to a higher-security cylinder before rekeying. This is a separate service from the rekeying itself but is frequently identified during the same visit.
Re-keying to a single key (keying alike). Property owners with multiple locks often want all exterior doors to operate on one key. This requires rekeying each cylinder — using the same key’s cut profile as the reference — a process that demands a full pin kit and careful sequencing to ensure every cylinder accepts the same key combination.
Smart lock integration. Some smart lock platforms include a cylinder that can be rekeyed to match existing home keys using a proprietary rekeying kit. When this process fails or the lock is from a brand without a consumer-accessible rekey kit, a locksmith can often remove and repin the cylinder manually.
Post-break-in security assessment. After a forced entry, pins inside the lock may be bent, springs may be compressed incorrectly from impact, and the cylinder may have shifted in the door. A professional locksmith will assess whether a rekey kit is sufficient to restore security or whether the lockset requires full replacement.
When to Call a Locksmith
A rekeying kit is a legitimate tool for property owners who have the patience, dexterity, and mechanical aptitude to use it correctly. However, calling a professional locksmith is the right choice in several specific circumstances: when the lock is a higher-security model with security pins or a restricted keyway, when multiple locks need to be keyed alike as part of a master key system, when a previous rekeying attempt has left the lock binding or non-functional, when the cylinder shows signs of wear or damage, or when the property has experienced unauthorized entry and a full security evaluation is needed alongside the rekey. A professional carries a complete rekeying kit with the full range of pin sizes, security pins, followers, and tools required for every common brand — Kwikset, Schlage, Medeco, Falcon, BEST, and others — and can verify the result on the spot. For locksmith work involving rekeying kits, lock repair, or any access-control concern, Low Rate Locksmith is available 24 hours a day, 7 days a week. Call (833) 439-8636 to speak with a technician who can reach you in your area, typically within the hour.
Related guides and references: Master Wafer, Residential Pin Tumbler Lock, Spool Pin, Common Problems With Lock Rekeying, Residential Paracentric Keys.