Accupro 778910 NMTB50 to JT3 Taper Adapter

Product Description

The ACCUPRO 778910 is an NMTB to Jacobs Taper adapter designed to connect a Jacobs Taper 3 (JT3) drill chuck to an NMTB50 spindle taper. The outside taper is NMTB50, which seats directly into a compatible machine spindle. The inside taper is JT3, accepting a standard Jacobs Taper 3 chuck arbor. The adapter has a projection of 1.3 inches and weighs 1 pound. Coolant-through capability is not supported. This part is used by machinists and tool crib technicians to mount drill chucks on vertical mills, drill presses, and machining centers equipped with NMTB50 spindles.

The 778910 is suited for shop environments where an NMTB50 machine spindle requires a JT3 chuck mount. Typical applications include vertical knee mills and drill presses in job shops, maintenance facilities, and production machine shops. The adapter allows use of standard Jacobs Taper 3 drill chucks without requiring a dedicated arbor. It is installed by machinists or toolroom technicians as part of tooling setup and changeover.

Key Features

• NMTB50 outside taper seats directly into NMTB50 spindles
• JT3 inside taper accepts standard Jacobs Taper 3 drill chucks
• 1.3 inches projection length
• No coolant-through passages — suited for dry and flood coolant operations where chuck-side coolant delivery is not required
• Compact 1 pound weight minimizes added spindle load

Compatibility

Designed for use with NMTB50 machine spindles and Jacobs Taper 3 drill chucks. Confirm spindle taper and chuck arbor taper before installation.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician. Power down and lock out the machine spindle before seating or removing the adapter. Ensure the NMTB50 taper and spindle bore are clean and free of chips or burrs before insertion. Do not force the taper; proper seating relies on clean mating surfaces and correct draw-bar engagement where applicable.