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 Primus): restricted Schlage
• 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:

• Blanks: each (standard);+ (restricted)
• Markup: typical 200-500% on duplication
• Customer pays: for standard duplicate; for restricted
• Wholesale machine investment:
• High-volume can be a profit center

For customer:

• Standard duplicate:
• Master / "high security" but unrestricted:
• Restricted (Medeco, Mul-T-Lock, Primus):
• Code cutting from scratch (no original):

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:
• Each key cut:
• Annual master key changes (optional):

ANSI / BHMA key designations

• A: highest pick resistance
• B: mid pick resistance
• C: standard pick resistance
• D: lowest

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 in bow; lock detects via reed switch; expensive.

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:

• Single key: all locks open with one key (master-keyed)
• Master + sub-master: primary key + secondary keys
• Top master: opens everything; submasters open subsets

Customer benefits:

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

Setup cost:

• Initial rekey of all locks: setup +
• New master key blanks per lock: each
• Documentation: handed to customer for future maintenance

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