Jacobs 7340DN Drill Chuck Arbor R8 Shank JT3

Product Description

The JACOBS 7340DN is a drill chuck arbor designed to connect a Jacobs Taper drill chuck to a milling machine or drill press spindle. It features an R8 shank for direct mounting into compatible R8-spindle machines and a JT3 (Jacobs Taper No. 3) mount taper on the chuck end. This arbor serves as the mechanical interface between the spindle and the chuck, transmitting rotational force and maintaining accurate chuck alignment during drilling operations. Machinists and tool-and-die technicians typically install this component when mounting or replacing a drill chuck on a vertical milling machine or floor-model drill press.

This arbor is suited for use in machine shop and industrial maintenance environments where R8-spindle equipment is standard. The JT3 taper mount accommodates drill chucks with a matching No. 3 Jacobs Taper bore. Typical applications include vertical knee mills and bench or floor drill presses equipped with R8 spindles. This part weighs 1.0625 pounds, making it a compact, solid component for direct-mount chuck installations.

Key Features

• R8 shank for direct installation into R8-spindle machines without an adapter
• JT3 (Jacobs Taper No. 3) mount taper for secure chuck seating
• Compact and solid construction at 1.0625 pounds
• Single-piece arbor design for reliable torque transmission and chuck alignment

Compatibility

Designed as an OEM-style replacement or direct-fit arbor for drill chucks with a JT3 bore mounted in machines with an R8 spindle taper. No specific model compatibility data was provided by the manufacturer for this listing.

Installation Notes

Installation and removal should be performed by a qualified machinist or maintenance technician. Power down and lock out the machine at the main disconnect before handling the spindle or chuck assembly. The arbor is typically seated by pressing or driving the chuck onto the JT3 taper; removal requires a chuck removal wedge or arbor press. Avoid striking the chuck or arbor with a steel hammer directly, as this can damage the taper seats.