Jacobs JCM6309 Keyed Drill Chuck JT3 Tapered Mount

Product Description

The JACOBS JCM6309 is a keyed drill chuck designed for use with JT3 tapered spindles on stationary and portable drilling equipment. It accepts round-shank tooling from 0.18 to 0.80 inches in diameter, covering a wide range of twist drills, step drills, and similar cutting tools. The chuck body is constructed of steel with a plain bearing design and a 2.54-inch sleeve diameter. At closed position, overall length measures 4.06 inches, dropping to 3.14 inches open. Tightening is performed with a K4 key, providing positive, repeatable clamping force suited to production and maintenance drilling operations.

This chuck is appropriate for drill presses, lathes, and other machine tools fitted with a JT3 Jacobs taper spindle nose. It is a common specification in industrial maintenance shops, fabrication facilities, and trade settings where consistent chuck runout is required. Total indicated runout (TIR) is rated at 0.004 inches, making it suitable for general-purpose hole-making work where moderate accuracy is needed.

Key Features

• Capacity range: 0.18 to 0.80 inches for broad tooling compatibility
• JT3 tapered mount for secure, interference-fit spindle attachment
• Keyed design with K4 key for positive clamping and repeatable grip
• Steel chuck body for durability in production and maintenance environments
• TIR of 0.004 inches for consistent general-purpose drilling accuracy
• 2.54-inch sleeve diameter with plain bearing construction

Compatibility

Designed to fit machine tool spindles with a JT3 (Jacobs Taper No. 3) tapered mount, including drill presses, lathes, and similar equipment configured for this standard taper.

Installation Notes

Installation should be performed by a qualified machinist or maintenance technician. Before mounting, ensure the machine spindle is fully powered down and locked out per OSHA lockout/tagout procedures. Clean both the spindle taper and chuck taper bore of oil, chips, and debris before seating. Drive the chuck onto the taper with a soft-faced mallet or arbor press to achieve full interference fit - do not hammer directly on the chuck sleeve or jaw assembly.