Accupro 784878 ER16 Collet 5/16 Inch 0.313

Product Description

The ACCUPRO 784878 is an ER16 series collet sized at 0.313 inches (5/16 inch) for use in ER16-compatible collet chucks on CNC machining centers, manual milling machines, and high-speed spindles. This collet grips round shank cutting tools including end mills, drills, and reamers, transmitting rotational force while maintaining concentricity during the cut. The ER16 series is a widely adopted standard in precision toolholding, and this collet fits within that system's defined clamping range. At 0.05 pounds, it is a lightweight, single-piece component. Machinists, toolroom technicians, and CNC setup operators are the primary installers.

This collet is suited for light to medium-duty machining applications in job shops, production environments, and toolroom settings. It accepts 5/16 inch shank tooling and seats into any ER16-standard collet chuck or nut assembly. Typical applications include profiling, drilling, and reaming operations on ferrous and non-ferrous materials. The compact ER16 form factor makes this collet a practical choice for smaller spindle configurations where toolholder envelope size is limited.

Key Features

• ER16 collet series — compatible with ER16-standard collet chucks and clamping nuts
• 0.313 inch (5/16 inch) collet bore for direct fitment of 5/16 inch shank tools
• Lightweight at 0.05 pounds — minimal added mass in high-speed spindle applications
• Single-piece collet design with standard ER-style slotted spring construction
• UNSPSC Code 27112800 — classified under precision toolholding components

Compatibility

Designed as a direct-fit collet for use in ER16-standard collet chucks. Compatible with any toolholder or spindle nose machined to the ER16 collet seat specification. Accepts 5/16 inch round shank cutting tools within the ER16 clamping range.

Installation Notes

Installation is performed by machinists or CNC setup technicians. Before seating the collet, ensure the spindle is fully stopped and the machine is in an e-stop or lockout/tagout state per applicable shop safety procedures. Insert the collet into the collet chuck before threading the clamping nut — do not tighten the nut onto the collet outside the chuck bore, as this can damage the collet seats. Inspect the collet bore and chuck taper for chips or contamination before assembly to maintain concentricity.