Pin-Tumbler Door Lock
The workhorse of residential security — a Kwikset knob or Schlage deadbolt is almost always a pin-tumbler cylinder. It is also the canonical locksport lock: single-pin picking a pin tumbler is the skill everything else builds on.
1. Anatomy
A pin-tumbler lock: a fixed housing above the shear line, a rotating plug below. Each chamber holds a spring, a driver pin (upper) and a key pin (lower). Notice the driver pins dip DOWN across the shear line into the plug — that overlap is exactly what stops the plug from turning.
How it works
A rotating plug sits inside a housing. Above the plug are five (or six) vertical chambers, each holding a coil spring, a driver pin on top, and a shorter key pin on the bottom. At rest, springs push the drivers down across the shear line — the gap between plug and housing — so the plug cannot rotate. The correct key lifts every stack exactly enough that the split between key and driver pins aligns to the shear line, freeing the plug. Picking recreates that alignment one pin at a time.
Tools you need
- A tension wrench — bottom-of-keyway (BOK) or top-of-keyway (TOK).
- A hook pick — a short hook or standard hook — for single-pin picking (SPP).
- A rake (city/snake rake or Bogota) for raking attempts.
Step-by-step technique
- Insert the tension wrench into the bottom of the keyway and apply very light rotational pressure — about the force of pressing a keyboard key — in the direction the key would turn.
- Find the binding pin. With that torque, one pin binds first due to manufacturing tolerances. Probe each pin with the hook and note which one is stiffest.
- Set the binding pin. Lift it slowly until you feel a slight give or hear a soft click — the plug will turn a hair. The driver has caught on the ledge above the shear line.
- Repeat. A new pin now binds. Find it, set it, and so on until all pins are set and the plug rotates fully.
- Raking alternative. With light tension, scrub a rake in and out while varying angle and height. If nothing sets within about ten seconds, release tension and start over.
Common mistakes
- Too much tension — pins jam below the shear line and won't lift.
- Too little tension — set pins drop back down when you move to the next one.
- Over-setting — lifting a stack so far the key pin itself passes above the shear line, where it gets trapped when the plug turns; relieve tension and reset that pin.
- Under-setting — not lifting far enough for the driver to clear the shear line, so the pin never sets; lift it a touch more rather than backing off.
- When stuck, reduce tension first. It's almost always tension.
Skill level & notes
Standard Kwikset and Schlage residential cylinders are very pickable by an intermediate hobbyist. Note that Kwikset SmartKey cylinders are not pin-tumbler — they use a wafer / sidebar mechanism that resists conventional picking, though it has its own well-known weaknesses.