nitrxgen
Lowe & Fletcher 92-series

The 92-series key codes from Lowe and Fletcher (L&F) are the most common key and code used for office filing cabinets. I have taken the liberty to collect information freely found on the Internet to produce a simple JavaScript-based conversion tool to switch between the blind code (usually stamped on the lock and/or key) and the bitting code (the sequence of depth-specific cuts on the actual key itself to operate the lock).

The GUI and display are currently under construction.

Information

First, let's talk about the thing we're presented with first: The blind code. The blind code is the sequence of numbers stamped on the key and/or lock cap. This code allows a user to produce replacement keys should one go missing. Unfortunately by displaying the blind code on the lock cap, this enables unauthorised users to order keys for themselves but let's not go into that.

These blind codes are typically displayed as a 3 digit or 5 digit number. For example: 92250 or just 250. The complete range is typically from 92201 to 92400 which allows for 199 unique locks and keys. These blind codes are used which then translate to a bitting code which is the sequence of numbers that represent the depth of each cut in however many positions. These keys have 5 cuts which may be one of 3 different specfic depths which allows a total of 243 unique keys but only 199 are used in the 92-series keys; so yes, 44 bitting codes are missing from the blind code list. Some of you may have noticed that there also exists 92001 to 92200 which translates the exact same to 92201 to 92400. Ranges 92401 to 92800 is actually the same bitting information but it specifies a different key profile (a mirror image key profile). For this reason, 92001 to 92800 is the accepted input blind code for this tool.

There exists a master key for all locks manufactured to accept the use of a master key. The master key works using the bitting code 12121 and a slightly different key profile which engages the opposite side of the lock's wafers. The opposite side of the wafers introduce the ability to use the master key.

The key blank required for the 92-series keys are available from a number of vendors: Anis (S8R), Borkey (959K, 959L), CEA (LF20, LF21S, LF41), Dominion Lock (H62DM, LF1, LF18, LF19, LF5), Errebi (LF10R, LF14R, LF30R, LF6R), Ezy Cut (C210), HD (85P, LF41, LF6), Ilco (LF1, LF18, LF19, LF5), JMA (LF15, LF1I), Keyline (LF16, LF20S, LF85), Kraga (U237, U241), Lotus (LW1, LW5, LW59), Mr Minit (24, 505), OZ (OZ210, OZ211), Orion (LF11Q, LF14LQ, LF39L), RR (LF10, LF13, LF58), RST (85P), Silca (LF31R, LF4, LF6R), Taylor (L192).

Measurements

The diagram shown above is actually an accurately measured representation of how the cut key should look. The blade of the key, where the cuts are made, is 6mm in height. A cut depth of 1, the shallowest, is 0.1mm deep. A cut depth of 2, the middle depth, is 0.85mm deep. A cut depth of 3, the deepest, is 1.6mm deep. Each cut has a flat spot 1mm wide for the lock's wafers to rest on. The first cut starts 3.7mm away from the key shoulder, this means the key blade should be at least 38.8mm long before the key begins to slope to the tip. From the deepest cut to the shallowest cut, a maximum permissable milling cutter of 86° is to be used with a 1mm flat. If the cutter has a wider flat cut, a smaller angle will be necessary.

Typically, these wafer-style locks will have their projections removed; this refers to their remnant slopes left over from cut to cut. These remnant slopes are left behind when a machine cuts into the key, removes the cutter, moves along, makes the next cut instead of continually feeding the cutter across the key and removing its projections. The benefit to removing the projections means less wear and tear on the lock's internal wafers since these are manufactured to be very cheap. Keeping the projections on all keys means the wafers are subject to a lot more friction and potentially more damage.

Things to do...
  • Option for removing projections from the cuts since 92-series keys usually are cut smooth
  • Return an error message upon invalid input
  • Style image options buttons better
  • A more accurate presentation (measurements) of the key profile
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