The Jacobs #JCM32282 Thread Mounted-Medium Duty Chucks - Model 41BA 3/8 from Industrial Hardware and Specialties, Inc. has a maximum capacity of 3/8", and a minimum capacity of 0.040". The keyed chuck ( Key Number K30 ) utilizes a 3/8-24 mount.

Jacobs #JCM32282 Thread Mounted-Medium Duty Chucks - Model 41BA 3/8

• Jaws Center-Ground for Absolute Straightness and Alignment.
• One-Piece Sleeve Eliminates Crack Between Driving Teeth Often Found in Other Designs.
• Through-Hardened Sleeve Teeth; Plus Hardened Nose and Keyholes Provide Outstanding Wear Resistance.
• Each Chuck 100% Inspected for Performance and Precision.
• T.I.R. .004 in Maximum at Half Capacity.
• Models 0 and 1A Are Smooth Sleeve.
• All Model 33 Plain Bearing Chucks Are Hammer Capable.