General Motors Progression Chart

This is a chart that is used when originating a key for the doors/trunk locks of GM cars. Typically, when a keyed glove box lock exists, cuts 3 through 6 are determined from the glove box lock. The 1st and 2nd cuts can then be determined, based upon the depth of the 3rd cut. The chart below provides for the orderly determination of the 1st and 2nd cuts. At most, 3 key blanks are needed by using this progressive procedure.
EVEN CHART
used when the sum of cuts 3 through 6 equals an even number
ODD CHART
used when the sum of cuts 3 through 6 equals an odd number
If
3rd
Cut
is a
1st
Key
2nd
Key
3rd
Key
1st
Key
2nd
Key
1 1-1
3-1
3-3
5-3
2-2
4-2
1-3 2-1
2-3
4-3
1-2
3-2
2 1-1
3-1
3-3
5-3
5-5
2-2
4-2
4-4
1-3
2-4
1-2
3-2
3-4
5-4
2-1
2-3
4-3
3 1-1
3-1
3-3
5-3
5-5
2-2
4-2
4-4
1-3
2-4
3-5
1-2
3-2
3-4
5-4
2-1
2-3
4-3
4-5
4 1-3
3-3
5-3
5-5
2-2
4-2
4-4
2-4
3-5
1-2
3-2
3-4
5-4
2-3
4-3
4-5
5 1-3
3-3
5-3
5-5
2-4
4-4
3-5 2-3
4-3
4-5
3-4
5-4


[Copyrite 1995, ClearStar Security Network]