HDZ Collet Holders

December 01, 2015

Even with minimal runout near the nose of the holder, conventional collet holders frequently see larger runout when measured at the cutting edge of longer tools. NT Tool’s original “R” Zero system eliminates this problem by utilizing a four-point adjustment mechanism to adjust runout at the tool tip to as low as 0µm to 2µm. The reduced runout of NT’s HDZ collet holders provides better surface roughness and invariant hole diameters than standard collet holders, making it an ideal choice for smooth finishing with ball end mills or reamers. 

The four-point adjustment system is simple, and the full procedure can be completed in less than a minute. Setup only requires a spanner to tighten the collet, and an adjustment wrench for the runout-adjustment screws. The adjustment ring can be rotated, allowing runout to be adjusted from any angle. 

Like many of NT Tool’s collet holders, HDZ holders use the company’s 12° taper FDC collets. By using a more gradual taper than 16° ER collets, FDC collets grip the cutting tool more evenly, increasing gripping force and reducing slippage. Metal-sealed coolant-compatible FDC collets have the added benefit of working without sealing rings, further decreasing downtime for routine setup and maintenance. 

HDZ holders are available in HSK, CAT (standard and two-face contact), BT (standard and two-face contact), and UTS shank styles. Standard collets cover a wide chucking range, and custom sizes are readily accommodated. 

The “R” Zero runout adjustment system is also available for NT Tool’s CTZ Holder for Large Diameters and PHZ-S Slim Hydraulic Chucks designed for machining in tight spaces.

Related Glossary Terms

  • collet


    Flexible-sided device that secures a tool or workpiece. Similar in function to a chuck, but can accommodate only a narrow size range. Typically provides greater gripping force and precision than a chuck. See chuck.

  • shank


    Main body of a tool; the portion of a drill or similar end-held tool that fits into a collet, chuck or similar mounting device.