Jacobs 7321N Taper Drill Chuck Arbor JT3 4MT

Product Description

The JACOBS 7321N is a taper drill chuck arbor designed to interface a Jacobs Taper 3 (JT3) drill chuck with a No. 4 Morse Taper (4MT) spindle or tailstock. The arbor serves as the precision link between chuck and machine, transferring rotational force without slip or runout. It is machined to standard taper specifications on both ends, allowing a secure friction fit at the shank and a positive seating at the chuck mount. Machinists, tool-and-die technicians, and maintenance professionals install this arbor on drill presses, lathes, and milling machines where a JT3 chuck and a 4MT spindle bore must be mated.

This arbor is suited to machine shop, maintenance, and production environments where a No. 4 Morse Taper spindle is present and a JT3-mount chuck is the preferred tooling. Typical applications include drill press columns with 4MT spindle bores and lathe tailstocks machined to 4MT specification. It is not limited to a single machine brand and is compatible wherever both taper standards are called for.

Key Features

• JT3 (Jacobs Taper 3) mount end accepts standard JT3 drill chucks
• No. 4 Morse Taper shank seats directly into 4MT spindle bores
• Friction-fit taper design on both ends provides secure, repeatable seating
• Lightweight at 1 pound, minimizing added spindle load
• UNSPSC classified under cutting and drilling tools (27112800)

Compatibility

Designed for use with JT3-mount drill chucks installed in machines equipped with a No. 4 Morse Taper spindle bore, including drill presses and lathe tailstocks machined to 4MT specification.

Installation Notes

A licensed machinist or qualified technician should install this arbor with the machine powered down and the spindle locked. Clean both taper surfaces of oil, grit, and burrs before seating to ensure full contact and prevent fretting. Drive the arbor into the spindle bore with a soft mallet or arbor press; never use a steel hammer directly on the taper. To remove, use the appropriate drift punch through the spindle drift slot to avoid damage to the taper surfaces.