Key Duplication That Works the First Time

What a Good Copy Has to Match

Hold a house key sideways and you're looking at a set of measurements, not just a shape. A working copy has to agree with the original, and with the lock, on every one of them:

• The keyway profile. The grooves milled along the blade that admit it to one family of cylinders and no other
• The blade length, which tracks the number of pin positions, usually five or six on residential hardware
• The stop. Most house keys locate against the cylinder face at the shoulder, while some keys, including many car keys, stop at the tip
• The spacing. The distance from the stop to the center of each cut
• The depth. How far each cut drops toward the bottom edge of the blade

Depth is where precision matters most. Manufacturers use a small set of standard depths with fixed steps between them. On Schlage residential cylinders each step is 0.015 inch; Kwikset uses steps of roughly 0.023 inch. A copy that misses a depth by half a step may still work in a crisp new cylinder and then stall in an older one, which is why copies so often work at one door and fail at another.

Spacing errors are just as unforgiving. If the original is clamped a little off its shoulder, every cut shifts down the blade by the same amount, and the pins come to rest on the slopes of the cuts instead of their flat bottoms. That kind of copy often turns only when you draw the key partway back out of the lock, a classic sign of a spacing problem rather than a depth problem.

Tracing Versus Cutting by Code

Locksmiths make copies on two kinds of machines, and choosing between them is the most important decision in any key duplication job.

A duplicating machine, often called a tracer, holds the original and the blank side by side in matched vises. As the carriage moves, a stylus rides along the original's cuts while a cutter wheel removes the same profile from the blank. On a clean key, a properly calibrated duplicator produces an excellent copy. Its weakness is that it copies everything, including wear, a bent tip, a burr, or a cut that was shallow from the factory.

A code machine works from numbers. The operator sets the bitting, a string of depth numbers for each position, and the machine cuts each position to that exact depth at the correct spacing for the brand. Once the code is known, the original isn't needed at all. Codes come from several places:

• Measuring the original with a key gauge, micrometer or caliper
• A code stamped on certain locks, especially cabinet, desk and padlock cylinders
• Records from an earlier rekey, installation or master key system
• The cylinder itself, read by decoding or disassembly

Our rule of thumb is simple. If the peaks are sharp, the valleys clean and the shoulder square, tracing is fast and accurate. If the peaks are rounded, the blade is polished, or the key has been in daily service for years, we decode it and cut to code. When it's a close call, we cut both ways and let the lock decide, because the lock is the final judge of any key.

Worn Keys and the Copy-of-a-Copy Problem

Every key wears where it meets the pins. Thousands of insertions round off the peaks between cuts, slowly deepen the valleys and dull the tip. The lock wears along with it, as pin tips and the plug's keyway polish themselves against that particular key. The pair keeps working long after either one would pass inspection on its own.

Trace that key and the copy inherits the rounding. Trace the copy and the duplicator's own small error stacks on top. A few generations later, someone is handed a key that only works with a lift and a wiggle, and nobody remembers where the original went.

Decoding breaks the cycle. We measure each cut from the bottom edge of the blade, compare the readings to the manufacturer's depth chart, and settle on the standard depth each cut was meant to be. Two rules help when a reading is ambiguous:

• Depths come in fixed steps, and wear only removes metal, so a cut that measures between two depths almost always belongs to the shallower one
• Each manufacturer limits how much neighboring cuts can differ, a rule called the maximum adjacent cut specification, which eliminates some combinations outright

The result is a key shaped like the factory original. In a cylinder that has worn heavily alongside the old key, that correct key can feel stiff at first. Cleaning and a dry lubricant fix many of these. If the pins themselves are worn, re-pinning the cylinder to a fresh code and cutting new keys to match is the honest, lasting solution, and it also retires every old copy in circulation.

Choosing the Right Blank

A surprising number of failed copies are cut perfectly on the wrong blank. Residential keyways come in dozens of profiles, and several look alike at a glance. A look-alike blank might slide into the cylinder but rub the wards, ride a hair low, or stop short of full insertion, and then even accurate cuts land in the wrong place.

We identify blanks from the stamp on the bow when there is one, then confirm by comparing the profile end-on against reference blanks. Pin count gets checked separately, because popular keyways come in more than one length. Both Kwikset and Schlage make five-pin and six-pin versions of their standard residential keyways, and a five-pin blank in a six-pin cylinder leaves the last pin stack sitting where no cut can reach it.

Material is the next choice:

• Brass. The residential standard, easy to cut and gentle on pins
• Nickel silver. Harder and more wear-resistant, a good fit for keys that see heavy daily use or work stiff commercial locks
• Aluminum and printed novelty blanks. Fine for occasional use, but many are softer and more prone to bending or snapping in a tight deadbolt
• Plated steel. Found on some padlock and specialty keys, tough on the key and on the cutter wheel

Finally, the head. Oversized decorative heads can be awkward beside a door frame or a lever rose, and a key that's hard to grip gets twisted harder than it should. A plain head with a colored rubber cap is often the more practical answer, especially for children and anyone with limited hand strength.

Do Not Duplicate Stamps: What They Mean

A key stamped Do Not Duplicate, often shortened to DND, tells you that whoever issued it wants control over the number of copies. It does not physically prevent copying. The blank underneath is usually ordinary, any compatible machine can cut it, and some sellers pay no attention to the stamp at all. On its own, the stamp is a statement of policy rather than a security feature.

We treat that policy as worth honoring. When a key is stamped DND, we ask for approval from the person or organization that issued it: the landlord, the employer, the association's management office, the school. A short written note, an email or a call from them is usually enough. Without it, we decline the copy and explain why, which is what you'd want a locksmith to do with keys you had issued.

Keys to public property are a firmer line. California law makes it a misdemeanor to knowingly copy, or to possess an unauthorized copy of, a key to a building controlled by the state, a state agency, a county, a city, or a public school or community college district, unless the person in charge of that building or a designated representative has authorized it. Many of those keys are stamped, but the legal rule applies whether or not a stamp is present.

If you're the one issuing keys and you want real control, a stamp alone won't deliver it. What works is a restricted or patented keyway, where blanks aren't available to the general public, combined with a list of authorized signers. The stamp then becomes a reminder of rules the hardware actually enforces.

Restricted Keyways and Signature Control

Between ordinary keys and full high-security systems sits the restricted keyway. The lock may look like any commercial cylinder, but its keyway profile is reserved: the manufacturer releases those blanks only to designated dealers, often with geographic protection, and only for cutting keys for the account holders on file.

Each restricted system typically comes with a registration card or record listing the people allowed to order keys. To get a copy, an authorized signer presents the card or signs a request, and the dealer checks the signature against the file. Some lines add utility or design patents, which give the manufacturer legal grounds to stop unauthorized blank production for the life of the patent. Patents do expire, though, and once protection on an older restricted line lapses, aftermarket blanks can eventually appear, so ask about the patent status before committing to a system.

For a business, this is the practical way to stop employees from making their own copies at a hardware counter. For an apartment community, it keeps unit keys from multiplying between turnovers. For a homeowner with a long list of contractors and helpers, it means the count of keys you hand out stays the count of keys that exist.

The flip side is that restricted keys can only be copied through the channel that holds the registration. If your system is registered with another provider, a copy has to come from them or the factory. We'll identify the line, tell you who can cut it, and if your paperwork is missing or you want control moved to you, outline what a new restricted system would involve. We don't make unauthorized copies of restricted keys, and a locksmith who offers to should worry you.

High-Security Keys and Why Ordinary Machines Can't Copy Them

High-security cylinders add mechanical features that a normal key's flat, two-dimensional cuts can't satisfy. The key has to do more than lift pins to the right height:

• Medeco keys carry angled cuts that both lift and rotate each pin so a sidebar can drop, and later generations add a slider operated by a feature on the side of the key
• Mul-T-Lock uses telescoping pin-in-pin stacks, so each position needs both an inner and an outer pin aligned at once
• ASSA and Schlage Primus cylinders add a sidebar controlled by a second row of finger pins, which read milling along the side of the key
• Abloy Protec2 uses no pins at all; a series of rotating discs must each be turned to a precise angle

Copying one of these keys requires the proprietary blank, a machine built for that geometry, and proper authorization, all at the same time. Many of these lines also carry key-control patents and a registration card with an authorized signer list, which is the real reason they resist casual copying.

What this means in practice: expect copies to take longer, cost more and involve paperwork. Keep the registration card somewhere safe and separate from the keys, update the signer list when owners or managers change, and count your keys from time to time. If the card is lost and you can't establish ownership of the system, the realistic choice may be new cylinders under a registration you hold.

We'll also tell you honestly when high-security hardware is more than a situation calls for. For a home that loses keys to a revolving cast of contractors, a restricted keyway on good Grade 1 hardware may deliver most of the key control at a lower cost.

Specialty Keys: Dimple, Tubular, Cabinet, Mailbox and Bit Keys

Edge-cut keys are only one style. Plenty of locks around a typical property use something else, and each needs its own blank and tooling.

• Dimple keys have shallow conical drillings in the flat faces of the blade. They need a machine that cuts perpendicular to the face, and orientation matters, since many dimple keys are reversible and cut on both sides.
• Tubular keys have a round shaft with cuts around its end. They show up on bike locks, vending and arcade machines, coin laundry equipment, alarm switches and some desk and display cases. A copy must match the pin count, commonly seven, and the position of the alignment notch.
• Cam lock keys for file cabinets, desks, lockers and RV compartments are often cut from a code stamped on the lock face. Common codes make copies easy, and they also mean a key from the same series may open your lock.
• Mailbox compartment keys for cluster boxes and apartment mail panels use small dedicated blanks. We copy a box holder's own key. We never copy carrier arrow keys or postal master keys; federal law, 18 U.S.C. 1704, makes counterfeiting postal keys a crime.
• Bit keys, often called skeleton keys, run interior mortise locks in older homes. Copies are cut and filed by hand to clear the wards and lift the lever correctly.

Padlocks deserve their own mention. Most brass and laminated padlock keys duplicate like house keys, while some shrouded or high-security padlocks use restricted or patented keys. When a property has many padlocks, a keyed-alike set is usually easier to manage than a ring of separate keys, and the copies you order afterward all come from one pattern.

Making a Key When There's Nothing to Copy

When the last key is gone, duplication has nothing to work from, but a key can usually still be made. Locksmiths call this originating a key, and on standard pin tumbler locks there are several ways to do it:

• Decoding the lock through the keyway with tools that read each pin's position
• Impressioning, where a blank is turned gently against the pins and filed at the marks they leave until it operates the lock
• Picking the lock open, removing the cylinder and reading the pins directly
• Cutting from a code stamped on the lock, which works for many cabinet, desk and padlock cylinders

Because originating hands a working key to someone who didn't have one, we verify ownership or residence before starting: photo ID together with something that ties you to the property, such as a deed, property tax bill, lease or utility bill. For a business, we need the owner, an authorized manager or a written work order. California's Locksmith Act, Business and Professions Code section 6980 and following, sets the rules for licensed locksmiths and is administered by the Bureau of Security and Investigative Services, and careful verification is part of doing this work responsibly.

Once the first key exists, spares are cut from its code, and we'll write the code down for you if you want it. Before ordering spares, though, ask one question: if every key was lost, could one of them have been found by someone else, especially on a ring with your address or your car? If the answer is yes, rekeying the lock is the safer next step, and copies of the new key follow naturally.

Why a Copy Fails, and How We Fix It at the Door

Testing at the lock is the step that separates a reliable copy from a lucky one. Here's what the common failures usually point to:

• The key won't go all the way in. A wrong or look-alike blank, a burr along the edge, debris in the keyway, or a tip left rough after cutting
• It goes in but won't turn. A depth off by a step, a spacing shift, or a lock that has adapted itself to a worn original
• It turns only when drawn slightly back out. Nearly always a shoulder or spacing error from how the original was clamped
• It runs the knob but not the deadbolt. The two locks were never keyed alike, or one of them was rekeyed at some point
• It turns with the door open but binds with the door closed. The bolt is dragging on a misaligned strike, a door problem rather than a key problem
• It sticks on the way out. Usually a burr or a dry, gritty plug

Each of these has a fix we can make on site. We deburr, recut by code, adjust or file the strike, or clean and dry-lubricate the cylinder. Where the cylinder itself is worn, we explain why re-pinning to a new code is the durable fix and quote it separately.

Our test protocol is deliberately fussy. Every copy goes into every lock it's meant to run, with the door closed and the bolt under load, through a full lock and unlock cycle in both directions. That routine catches the binding deadbolt and the garage-entry door everyone forgets, before you're the one relying on the copy on a cold morning.

Key Control for Businesses and Rental Properties

For an office, shop, warehouse or rental property, key duplication is one piece of a larger system. Every copy is access, and access you can't account for is a risk you can't measure.

A simple key control program has four parts:

• An inventory of every cylinder and the key that operates it
• Stamped control numbers on each key, so two identical keys can still be told apart
• A log recording who received which number, when, and who approved it
• A regular count, plus a rule that departing staff return keys before their final paperwork is processed

Master key systems need extra care. A master opens a group of doors and a grand master opens nearly all of them, so copies of those keys should be rare, approved by the owner and recorded every time. Interchangeable core systems add a control key that removes the cores themselves; it deserves the tightest handling of any key on the property.

We cut copies for commercial cylinders, including mortise, rim, storefront and interchangeable core types, stamp them on request and leave a list of exactly what was cut. For designing a new hierarchy, keying charts and long-term record keeping, our master key system service covers planning the system itself.

Landlords benefit from the same discipline. A key count per unit, recorded at move-in and move-out, makes it obvious when a turnover rekey is required rather than optional. Copies for an incoming tenant should be cut from the recorded code, not traced from whatever key the last tenant happened to return.

Cost Factors, Scheduling and Where We Work

We don't publish fixed prices for key duplication because the variables are real ones. Here's what moves a quote:

• The blank. Standard brass, nickel silver, a specialty profile or a controlled high-security blank
• The method. Tracing a clean key versus decoding and code cutting a worn one
• Quantity. Several copies of one key versus single copies of many different keys
• Authorization and factory ordering for restricted and patented keys
• The service call, since we come to your home or business and the trip is part of the job
• Any lock work, such as cleaning a gritty cylinder or re-pinning a worn one

We quote before cutting anything, and many customers fold copies into a rekey or lock repair so one visit handles the lot.

Julian's Locksmith is a mobile locksmith based in San Bernardino and licensed by the California Bureau of Security and Investigative Services under license LCO7891, which you can look up at search.dca.ca.gov. We serve the Inland Empire, the San Gabriel Valley, the Pomona Valley, north Orange County and southeast Los Angeles County. Our hours are 6:30 a.m. to 11:30 p.m., seven days a week. That includes weekends. Call (951) 903-3193, tell us which keys you have and how many copies you need, and we'll give you a quote and an honest ETA.