Pin Tumbler Locks

Also known as Yale lock, uses pins of various lengths to prevent lock from turning without correct key to push pins
Most commonly used on residential and commerical doors, but also in padlocks
5-pin cylinders are very widespread in home locks, but for added security, may use 6/7 pins

Duplicate Keys

The KW1 keyway by Kiwiset, is the most common key for residental locks.

Type	Tolerance	Notes
Master pins	±0.001 to ±0.002 in (±0.025–0.05 mm)	Master wafers must be very consistent to avoid creating vulnerabilities.
Bottom pins	±0.0015 to ±0.003 in (±0.038–0.076 mm)	These are the pins that align with the key cuts.
Top pins (drivers)	±0.001 to ±0.003 in (±0.025–0.076 mm)	Tighter tolerances improve resistance to lock picking.
Shear line tolerance (total clearance)	~0.003 to 0.006 in (0.076–0.15 mm)	This is the key measurement that determines how precisely a key must match.

For KW1 keyways tolerances are relatively loose compared to high-security locks.

Spacing:

Feature	Typical Value
Key cuts depth range	1 to 6 (Kwikset uses 6 depth increments)
Cut depth increments	0.023" (0.584 mm)
Bottom pin lengths	~0.169" to ~0.284"
Pin length tolerance	±0.0015" to ±0.003" (0.038–0.076 mm)
Shear line clearance	~0.004" to 0.006" (0.10–0.15 mm) total clearance
Driver pin tolerance	±0.002" typical

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