Invalid Key Bitting Generator

Terminally invalid key bittings: research, analysis, and generator

What’s new

• Added modeling for manufacturer constraints beyond MACS:
  • No-cut/forbidden stations
  • Station-specific depth ceilings
  • Stop type (shoulder vs tip) and minimum first station
• Added presets: US, Euro, Kwikset SmartKey 6-key used in 5-pin plug, Schlage Everest full-size, Schlage Everest 29 SL tip-read, BEST A2 tip, Yale KeyMark conventional, Yale IC A2 tip, ASSA ABLOY Yale conventional
• Added CLI: check, repair, list-terminal, enumerate, presets

Key findings with citations

• Kwikset SmartKey forbidden station for 5‑pin plug when gauging a 6‑pin key: “0-position on the key is not used… do not gauge the 0-position.”

  • /home/ubuntu/research/locks/kwikset_rekey_manual.txt lines 639-646

• Schlage Everest full-size OEM data: MACS=7; Increment=0.15"; Spacing tolerance ±0.001"; Depth tolerance +.002/−0.

  • /home/ubuntu/research/locks/schlage_everest_fullsize_manual.txt lines 909-931

• Schlage Everest cutting guidance: first-cut positioning can be mis-set if carriage travel is restricted by bow geometry; confirms setup/stop constraints matter.

  • /home/ubuntu/research/locks/schlage_everest_fullsize_manual.txt lines 1403-1409

• Schlage catalog: shoulder stop is the datum while bittings are read tip-to-bow for certain families; establishes stop rule governing first-station permissibility.

  • /home/ubuntu/research/locks/schlage_catalog.txt lines 1636-1643

• Yale KeyMark Service Manual: A2 pinning with MACS: 9, Increment: .0125", Depth Tol ±0.0015", Spacing Tol ±0.0010", and “SPACING FROM THE SHOULDER” indicating shoulder-stop stationing.

  • URL: https://www.sopl.us/uploads/1/3/0/1/1301029/yale_keymark_service_manual.pdf
  • Extracted: /home/ubuntu/research/locks/yale_keymark_manual.txt lines 456-463, 489-491

• ASSA ABLOY Yale Cylinders & Keys Catalog: SFIC “keys are cut from tip to bow” and section/read conventions; supports tip-read preset and general Yale conventions.

  • URL: https://www.assaabloy.com/hk/en/product-assets/cylinder/yale4/assets/documents/Yale_Cylinders_and_Keys_Catalog.pdf
  • Extracted: /home/ubuntu/research/locks/yale_cylinders_keys_catalog.txt lines 1258-1259, 1328-1329

• best_a2_tip: BEST A2, tip-stop preset (A2 increment context), with a conservative minimum first station from tip

• Schlage Everest 29 SL: read standard cuts with key gauge starting at the tip; SFIC A2 uses 0.0125" increment (context for increments/standards).

  • /home/ubuntu/research/locks/schlage_everest29_sl_manual.txt lines 2514-2517 and 2123-2128

Why terminal invalidity exists

• MACS + global depth range alone is monotone under deepening; any sequence within max depth can be deepened to satisfy MACS.
• Terminal invalidity arises when constraints are not monotone under deepening:
  • A cut at a forbidden/no‑cut station cannot be removed by deepening.
  • A cut before the minimum allowed first station for the stop type cannot be moved by deepening.
  • A station-specific ceiling lower than global max makes any deeper cut at that station unfixable by deepening.

Model

• KeySystem fields now include:
  • stop_type: shoulder or tip
  • min_first_station_index: earliest allowed station index for a cut
  • no_cut_mask: per-station boolean disallow
  • station_max_ceiling: per-station maximum depths
• Validation checks these before and after MACS repair. Repair is linear-time propagation; no recursion.

Presets

• us: generic 5-pin, depths 1..7, MACS 2
• euro: generic 5-pin, depths 1..10, MACS 2
• kwikset_6in5: 6-pin key used in 5-pin plug; station 0 is no-cut
• schlage_everest_full: MACS 7, shoulder stop
• schlage_everest29_sl_tip: MACS 7, tip-read; min_first_station_index defaults to 1 to demonstrate tip-stop constraints
• best_a2_tip: BEST A2, tip-stop; conservative min-first-station from tip
• yale_keymark: Yale KeyMark conventional, shoulder stop; stationing by shoulder datum
• yale_ic_a2_tip: Yale SFIC A2-style tip-read; min_first_stn=1
• assa_abloy_yale: Yale conventional under ASSA ABLOY catalog; shoulder stop

CLI

• Show presets: python3 tool.py presets

• Check: python3 tool.py check --preset kwikset_6in5 --seq 2,1,1,1,1,1

• Repair: python3 tool.py repair --preset us --pins 5 --seq 1,7,1,1,1

• Generate terminal examples:

• BEST A2 tip-stop check: python3 tool.py check --preset best_a2_tip --seq 2,1,1,1,1,1,1

• Yale IC A2 tip-stop check: python3 tool.py check --preset yale_ic_a2_tip --seq 2,1,1,1,1,1,1

• Yale KeyMark terminal examples: python3 tool.py list-terminal --preset yale_keymark --limit 5

• ASSA ABLOY Yale terminal examples: python3 tool.py list-terminal --preset assa_abloy_yale --limit 5

  python3 tool.py list-terminal --preset schlage_everest29_sl_tip --limit 5

• Enumerate small spaces: python3 tool.py enumerate --preset euro --pins 4 --max-repeat 4

Examples

• Kwikset 6→5 case:
  • Input: 2,1,1,1,1,1
  • Check: terminal=True reason=forbidden/no-cut station cut present
• Shoulder stop first-station restriction (if min_first_station_index=1):
  • Input: 2,1,1,1,1,1
  • Check: terminal=True reason=first station not allowed for this stop type
• Station ceiling example (configure --ceilings None,4,None,None,None,None and put 5 at pos 1):
  • Input: 1,5,1,1,1,1
  • Check: terminal=True reason=station-specific ceiling violated

Run locally

• cd /home/ubuntu/work/key_bittings
• python3 tool.py presets
• Use the commands above to verify terminal invalidity under manufacturer constraints.

Notes

• Euro EN 1303/18252 public summaries are performance-classification oriented and do not include cutting geometry; OEM documents govern practical station/stop constraints.
• The model accepts future numeric station ceilings when OEM tables are found; examples here are illustrative but the Kwikset no‑cut and Schlage stop rules are directly cited.