Hold collets tightly in older CNC machines with NMTB taper spindles for milling, drilling, and routing. The shank on these chucks is precision ground to the industry standard AT3 tolerance—or better—for a secure fit that minimizes runout in your machine spindle. Internal threads in the shank connect to your machine's drawbar.

Insert your collet and tighten the nut to clamp your tool in place.

To maximize grip and minimize runout, choose a chuck where your tool diameter falls in the middle of the bit shank size range.