Rekeying: what the job needs
What rekeying is, when it beats replacing a lock, the tools and pin kits the job needs, and how to keep a customer on one key across a property.
Rekeying changes which key operates a lock without replacing the hardware. It is faster than swapping the cylinder, it costs the customer less, and it is most of the residential and commercial work in this trade.
When to rekey and when to replace
Rekey when the hardware is sound and only the key needs to change: a tenancy ends, a key goes missing, a contractor is finished, or a property changes hands. Replace when the cylinder is worn, damaged, or the wrong security grade for what the customer now needs.
The judgement is about the condition of the lock, not about the reason for the change.
What the job needs
- A pin kit for the brand and system in front of you. Pin sizes are not interchangeable between manufacturers.
- A follower and plug holder, so the top pins and springs stay where they belong when the plug comes out.
- Tweezers and a tray. Rekeying is small parts management more than anything else.
- Blanks in the right keyway and a way to cut them.
Brand specific rekeying kits exist because the alternative is owning every pin size in every increment, and most of them will never come out of the tray.
Keying alike, and master keying
Keying alike puts one key across several locks, which is what a customer usually means when they ask for their front and back door to match. It is the same rekeying procedure applied to each cylinder with the same bitting.
Master keying is a different problem: two or more keys operate the same lock at different levels of authority, achieved with extra wafers in the pin stack. It needs a plan before it needs tools, because a badly designed system creates keys nobody intended to issue.
Getting the bitting
With a working key, decode it or read the cuts directly. Without one, a 2-in-1 pick and decoder reads the lock itself and gives you the bitting without removing the cylinder, which is the fastest route on a lockout.
Questions
How many times can a cylinder be rekeyed?
Many times. The limit is wear on the plug and the keyway rather than a fixed count.
Do I need a different pin kit for every brand?
For the brands you work on regularly, yes, because pin lengths and increments differ. Brand specific kits are cheaper than assembling the same coverage from a universal kit.
Can I rekey a smart lock?
If it has a mechanical override cylinder, that cylinder rekeys like any other. The electronic credential side is a separate exercise handled through the lock's own programming.
About this guide
This is general information about how the work is normally done, not advice for the particular vehicle, lock or machine in front of you. It does not replace manufacturer instructions, training, or your own judgement about whether a job is within your competence. Specifications and fitment change between model years, so check the code on the original part before you buy or cut anything. See the terms.