How to read a Keyzee pin chart
Every column explained, with the bench logic behind each one. By the end you should be able to look at a chart and know what to drop into each chamber without re-checking the schedule.
The chart layout
A Keyzee pin chart for a 6-pin Lockwood 570 cylinder looks like this:
Door D-103 — Lockwood 570 — 6-pin
Position: 1 2 3 4 5 6
Bottom (BP): 3 5 2 6 4 7
Master (MP): 2 - 3 - - 1
Driver (DR): 5 5 5 4 6 2
Total stack: 10 10 10 10 10 10
Cylinder height: 10
Six positions, one column each. Read each column top-to-bottom — that's the order pins drop into the chamber from the keyway side.
Position
The pin position, numbered from the bow (closest to where the key enters) toward the tip. Position 1 always loads first.
Bottom pin (BP)
The pin that touches the key. Its height equals the change-key cut depth at that position. 3 at position 1 means the change key has a depth-3 cut at position 1, so a depth-3 bottom pin sits flush at the shear line when that key is inserted.
Master pin (MP)
The thin spacer that creates a second shear line so the master key can also turn the cylinder. A dash (-) means no master pin at that position — the master and change key share that depth, and a single bottom pin handles both.
At position 1 in the example, MP=2 means the master cut at position 1 is 2 deeper than the change cut (3+2=5). Insert the master key, the bottom pin (3) and master pin (2) stack to 5, and the gap above the master pin lands at the shear line.
Driver (DR)
The pin pushed down by the spring. It sits above the shear line until a key with the right combination pushes it up. Driver heights vary per position so the total stack always matches the cylinder chamber height (here, 10).
Total stack & cylinder height
Add BP + MP + DR per column — must equal the cylinder height (10 in this example). If any column doesn't add up, the chamber is over- or under-filled, the key won't turn or won't return. Keyzee guarantees this on every build; the chart shows you the math.
What about thin master pins?
A "thin master pin" warning means an MP value is at or below the cylinder's minimum (2 by default — most cylinders won't tolerate a 1-thick disc; it tilts in the chamber and jams).
On the chart, a thin pin shows highlighted in amber. You can either accept it (Keyzee proceeds; some cylinders do tolerate thin pins — early American Standard, some European sport keyways) or regenerate the system with a different variation seed until the engine finds bittings without thin pins.
How this maps to the bench
Lay your pinning kit out left-to-right by position. For each chamber:
- Drop the bottom pin (BP value) first.
- Drop the master pin (MP value), if there is one. If MP is "-", skip.
- Drop the driver (DR value).
- Drop the spring on top.
Cap the chamber, move to position 2, repeat. Six chambers per cylinder, ten cylinders per system, you're done in about 25 minutes — and the chart format is the same for every cylinder, every system, every brand.
What about IC cores and SFIC?
SFIC and other interchangeable cores (BEST A2, Falcon FK, Arrow IC) have a control shear line in addition to the operating shear line. The Keyzee chart adds a Control (CTL) row showing the control pin per position. Same logic — bottom + master + driver + control = chamber capacity. See SFIC in the glossary for the full mechanism.
Print the card, take it to the bench
From the system view, click Export → Workshop pinning card (PDF). The PDF prints clean on A4 or letter. One page per cylinder; door label and key schedule reference printed at the top.