Draw a table on a piece of graph paper with a pencil or in a spreadsheet program. The number of columns equals the number of doors the keys are compatible with. The number of rows equals the number of keys required.
A matrix master key graph, sometimes called a matrix master key chart, displays the keys or key holders in a building and the doors that can be opened by those keys. Locksmiths use the matrix master key graph to cut each key according to a client's specifications. You can create a matrix master key graph using graph paper or a spreadsheet program after you determine how many keys you require and which doors each key should open.
Label the top of each column with the door's name. If the doors are numbered, use each door's number. Alternatively, use descriptive text, such as "conference room" or "small lecture room," if door numbers aren't available.
Label the left side of each row with a key number or name. The key numbers or names represent the keys you require.
Insert an "X" in a cell where a key's row intersects with the column of a door it can open. For example, if "Key 1" opens "Door 2" and "Door 3" but not "Door 1," insert an "X" in the two cells where the row labeled "Key 1" intersects with the columns labeled "Door 2" and "Door 3." Repeat for each key in the table.
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