Parlec 5UMER20-0312 ER20 Collet 5/16 Inch

Product Description

The PARLEC 5UMER20-0312 is an ER20 series collet designed for precision workholding in CNC machining and milling applications. It accepts a nominal collet size of 0.3125 inches (5/16 inch) with a minimum collet capacity of 0.273 inches, giving it a working clamping range suited to a variety of round shank tooling. The collet holds a Total Indicator Runout (TIR) of 0.0002 inches, making it appropriate for applications where concentricity and repeatability are critical. Overall length is 1.24 inches and overall diameter is 0.827 inches. Licensed machinists and CNC setup technicians are the primary installers of this component.

This ER20 collet is suited for use in standard ER20-compatible collet chucks and tool holders mounted in vertical machining centers, horizontal machining centers, and CNC milling machines. The ER20 standard is one of the most widely used collet systems in production and job-shop environments, making this collet a common replacement or additional-capacity item for shops running 5/16-inch shank end mills, drills, or reamers.

Key Features

• ER20 series collet with 0.3125 inch (5/16 inch) nominal collet size
• Minimum collet capacity of 0.273 inches for range clamping flexibility
• TIR of 0.0002 inches for high-precision, low-runout toolholding
• Compact overall length of 1.24 inches fits standard ER20 chuck pockets
• Overall diameter of 0.827 inches consistent with ER20 dimensional standards

Compatibility

Designed for use with ER20-compatible collet chucks and tool holders conforming to the ER20 collet standard.

Installation Notes

Installation is performed by a machinist or CNC setup technician. The collet should be seated fully into the ER20 collet nut before insertion into the chuck body - never torque a collet into the chuck without the toolholder nut engaged. Ensure the machine spindle is fully stopped and the tool changer or spindle lock is engaged before changing collets. Inspect the collet bore and seating taper for chips or debris before assembly to maintain rated TIR performance.