Key Blanks + Duplication Reference

Overview

Key duplication is a daily locksmith service. Understanding blank types, cutting techniques, + restricted-key policies is foundational.

Key blank anatomy

• Head / bow: end held by user (often plastic-coated)
• Shoulder: stops key at correct depth in lock
• Blade: portion inserted into lock
• Bittings: cuts on the blade (where the keyway pins rest)
• Tip: end of blade (sometimes pointed; sometimes flat)
• Keyway profile: cross-section of blade (matches the lock's keyway groove)

Key blank identification

Identifying a key requires matching:

1. Keyway profile (cross-section): each manufacturer's keyway is unique
2. Length: blade length matches the lock
3. Bow shape: aesthetic, sometimes branded

A locksmith reads:

• Code stamped on key (some manufacturers stamp blank ID)
• Bow shape + profile: experienced locksmith identifies visually
• Lock manufacturer: customer often knows

Common blanks:

• KW1 (Kwikset): most common residential
• KW10 (Kwikset SmartKey): more recent Kwikset
• SC1 (Schlage): standard Schlage
• SC4 (Schlage): standard Schlage 6-pin, unrestricted like SC1. Primus is a restricted keyway with its own blanks, not SC4
• WE1 (Weiser): Weiser brand
• Y1 (Yale): standard Yale
• M1 (Master Lock): padlock standard

Duplication methods

Method 1: Mechanical key duplicator

The traditional machine:

1. Insert original key + matching blank
2. Tracer follows bittings of original
3. Cutter cuts matching bittings into blank
4. Inspect, deburr, smooth edges
5. Test in customer's lock if possible

Process time: 1-2 minutes per key.

Accuracy: ±0.001" achievable with quality machine; ±0.005" common.

Cost: machine.

Method 2: Code cutting

For keys where you have the code (no original key):

• Code is the depth at each pin position (5-6 numbers)
• Code cutter machines: pre-program the code; cuts directly into blank
• Used when:
  • Original key lost
  • High-security with code on file
  • Customer wants spare without showing original

Cost: machine.

Method 3: Impression

Older + specialty technique:

• Insert blank into lock
• Apply torque (binding pressure)
• File marks where pins bind
• File bittings progressively until lock opens
• Slow, specialty skill

Used for: high-security locks without code, custom situations.

Method 4: Decoding (advanced)

For some lock types, decoding the lock reveals the bitting:

• Specific lock manufacturers' locks decode-able
• Service code reads pin positions
• Cut blank to decoded specifications

Specialty + manufacturer-dependent.

Restricted vs unrestricted keys

Unrestricted (most residential):

• Blank widely available at hardware stores, big-box
• Anyone can buy + duplicate
• Convenient + cheap
• Low security: anyone can copy

Restricted (high-security):

• Blanks only available from licensed locksmiths
• Lock owner must authorize duplicates (often in writing)
• Manufacturer tracks all blanks sold
• Examples: Medeco, Mul-T-Lock, Schlage Primus, BiLock
• More secure: prevents unauthorized duplication

For customers with security concerns: upgrade to restricted system.

Patent + manufacturer protection

• Patent-restricted: protected by patent; manufacturer controls
• Trademark-restricted: blank shape trademarked
• Code-restricted: locks coded; blanks tracked by code

Most restricted systems combine multiple methods.

Common duplication issues

Wrong blank:

• Bow shape similar but profile slightly different
• Key inserts but won't turn (or only partially)
• Solution: identify correct blank; recut

Bittings too deep:

• Pin doesn't reach shear line
• Lock won't operate
• Solution: recut with proper depth

Bittings too shallow:

• Pin pushed too high
• Lock won't operate
• Solution: recut with proper depth

Worn bittings (smooth edge):

• Modern keys should have sharp bittings
• Worn key may not push pins correctly
• Solution: cut new key from blank using original as template (NOT a recut of worn key)

Cost considerations

For locksmith business:

• Blank cost: a standard pin-tumbler blank is pennies in bulk. A high-security or restricted blank runs an order of magnitude higher and has to come through the authorized channel.
• Markup: 200 to 500 percent on standard duplication is typical, because the customer is buying the machine, the skill, and the thirty seconds, not the brass.
• Machine investment: a duplicator plus a code machine is a significant one-time bench cost, paid back over hundreds of cuts. Add a laser or milling machine only when automotive volume justifies it.
• High-volume duplication is a profit center on margin percentage, not on ticket size. It works when the keys are cut between other jobs, not when a tech drives to a site to cut one.

For customer, in multiples of a standard duplicate:

• Standard duplicate: baseline. Fast, walk-in, no paperwork.
• Master or "high security" but unrestricted (bump-resistant, tighter tolerance profiles): roughly 2 to 4x baseline. Blank costs more and the cut has to be more precise.
• Restricted (Medeco, Mul-T-Lock, Primus and similar): roughly 5 to 15x baseline. Authorized-dealer-only blanks, a signature check against the system's authorization card, and often a lead time rather than a wait.
• Code cutting from scratch (no original to copy): priced as a service call plus bench time, not as a key. You are billing the code lookup or the lock disassembly to read the pinning, the cut, and the on-site test, so it lands well above any duplication tier. Verify ownership before you cut, and expect the restricted-system rules to apply on top if the system is restricted.

Restricted-key system business model

For premium customers:

• Customer enrolls property in restricted system
• Authorization form on file at locksmith
• Each key cut requires customer authorization
• Audit trail of who has keys
• Premium upgrade for security-conscious customers

Locksmith collects ongoing revenue:

• Initial system install: the largest single ticket. Cylinders or cores for every opening, the system design and bitting schedule, the pinning labor, and the install. Quoted per opening.
• Each key cut: recurring, at the restricted premium, and it comes with the authorization check and the log entry. Every new hire, every lost key, every added contractor is a call to you and nobody else.
• Annual master key changes (optional): a scheduled re-pin of the master level, priced per opening plus a new key set for every holder. Sell it to customers with real turnover (property management, healthcare, multi-shift facilities) as a security-hygiene subscription rather than a one-off.
• The durable value is the tie: the customer cannot get a key anywhere else, so the system keeps producing service calls for its whole life. That is why restricted systems are worth designing and documenting properly on day one.

ANSI / BHMA key designations

• A: highest pick resistance
• B: mid pick resistance
• C: standard pick resistance
• (BHMA A156.30 defines Grade A, B and C only; A is the highest attack resistance)

Higher level = more secure (anti-pick + anti-bump features).

Specialty key types

Bump-resistant keys: additional bittings to defeat bumping; require precise duplication.

Magnetic keys: small magnets set into the blade; the cylinder's magnetic tumblers only align when polarity and position both match. Still a purely mechanical lock, not an electronic one. Expensive and duplication is manufacturer-controlled.

Electronic keys: RFID, transponder, contactless; common in automotive + commercial.

Smart keys: physical bow + electronic chip; emerging high-end.

Key blank inventory for a locksmith

Standard residential stock:

• KW1 (Kwikset): bulk
• SC1 (Schlage): bulk
• KW10 (Kwikset SmartKey): standard
• Y1 (Yale): standard
• M1 (Master Lock): standard
• 10-15 other common blanks

Specialty stock (high-volume locksmith):

• 100+ blank profiles
• Restricted system blanks (after enrollment)
• Automotive blanks
• Padlock blanks

Key wear over time

• Standard residential: 5-10 years before noticeable wear
• High-use (commercial, daily): 2-5 years
• Symptoms: harder to insert, harder to turn, dull bittings visible

When customer complains about key issues, check wear first.

Master key systems (residential)

For larger residential properties:

• Keyed alike: every lock takes the same key. Simple, but it is not master keying - there is no way to hand someone access to one door and not the rest
• Master keyed: each lock keeps its own change key AND also accepts a master. That is the difference: two key levels per cylinder, not one key for everything
• Top master + submasters: the top master opens everything; each submaster opens a defined subset; change keys open single doors

Customer benefits:

• One key for entire property
• Hand out limited-access keys to staff/visitors

Setup cost, in multiples of a single standard rekey:

• Initial rekey of every opening into the system: per-opening rekey labor plus a one-time design charge for the bitting schedule. The design is the part customers do not expect to pay for and the part that makes the system work
• Key sets: a change key for each opening plus the master and any submasters, priced per key at the tier the system runs on
• Documentation: the bitting schedule and key-holder log, handed to the customer. Keep your own copy; you will need it for every future addition

When to recommend restricted key system

• Customer concerned about ex-employees / past tenants
• Property management with rotating tenants
• High-value contents
• Commercial-grade security desired
• Customer willing to pay premium

References

• ALOA standards
• Manufacturer technical specs (Medeco, Mul-T-Lock, Schlage Primus)
• Manuall internal: Lock Types + Mechanisms Reference, Rekey + Lock Change SOP