Below is a summary of all the known Jacobs chuck keys

Model Number
With Link
Handle Style Code Chuck series Note
K0 Bright T-Handle JC0003637 0 Series
K0M Bright T-Handle JC0003639 0 Series Stainless
K1 Bright T-Handle JC0003641 1 Series
K1M Bright T-Handle JC0003643 1 Series Stainless
K2 Bright Thumb Handle JC0003649 2 Series
K3 Black T-Handle JC0002518 3, 34, 35, Series &14N Obsolete use K3B
K3B Bright Thumb Handle JC0003651 3, 34, 35, Series &14N
K4 Bright Thumb Handle JC0003655 36 Series, 16N & 18 N
K5 Bright T-Handle JC0003657 20N
K7 Bright Thumb Handle JC0003659 7 Series
K30S Black T-Handle JC0002520 31, 41, K13AC30 Series & 81/2N Obsolete use K30B
K30B Bright Thumb Handle JC0003664 31, 41, K13AC30 Series & 81/2N
K32 Black T-Handle JC0902522 32, 33 Seriesv& 11N Obsolete use K32B
K32B Bright Thumb Handle JC0003666 32, 33 Seriesv& 11N
KG Black T-Handle JC0902505 K10 ACG Series & Adaptadrive, DCG & SMG Series
KS2 Black T-Handle JC0902535 Craft Chucks with 8/10 Metric Gearing
KK Black T-Handle JC0030052 DC8, SM8 Series