Jacobs 9 Drill Chuck Key K4 3/8 Inch Pilot Diameter

Product Description

The JACOBS #9 is a drill chuck key designed to tighten and release drill chucks in shop and field applications. Keyed to the K4 standard, it features a 3/8 inch pilot diameter that seats precisely into the chuck body for positive engagement. This type of key is a consumable hand tool used by machinists, millwrights, electricians, and general tradespeople wherever a keyed drill chuck is in service. Losing or damaging a chuck key is a common job-site occurrence, and this replacement restores full chuck function without requiring a new chuck assembly.

The JACOBS #9 K4 chuck key is intended for use with compatible JACOBS drill chucks mounted on benchtop drill presses, handheld corded drills, and similar rotating equipment in light industrial and trade environments. It is a direct OEM-style replacement keyed to match specific JACOBS chuck models. Compatible chuck models are listed in the compatibility section below. The compact size and straightforward design suit both shop technicians maintaining stationary equipment and field tradespeople carrying portable drill units.

Key Features

• K4 key number for precise engagement with compatible JACOBS chuck bodies
• 3/8 inch pilot diameter for accurate pilot-hole seating
• Sized as a direct OEM-style replacement to restore chuck function quickly
• Single-piece unit sold individually, no additional hardware required
• Lightweight at 0.35 pounds for easy handling and storage

Compatibility

Compatible with JACOBS drill chuck models 16N, 18N, 36, 36B, 37KD, 37PD, and 59B, as specified by the manufacturer.

Installation Notes

Insert the pilot pin fully into the chuck body pilot hole before applying torque to ensure proper seating and avoid damage to the chuck teeth. Power down and disconnect or unplug the drill or drill press before changing bits or servicing the chuck. No special tools beyond this key are required for standard bit changes. Replace the chuck key if the pilot pin or gear teeth show visible wear, as a worn key can damage the chuck ring gear over time.