Lock tool holders in place on CNC machines with a through-spindle coolant (TSC) system. They fit machines with a CAT taper spindle. All meet industrial standards for tensile and shear strength. Also known as pull studs. Use a torque wrench with a retention knob socket or a changeable-head torque wrench to tighten them.

To ensure compatibility with your machine, compare the features on these knobs, such as the location of O-ring seals and the pilot design, to those on your current knob.

Knobs with a pilot ensure precise alignment between the tool holder and spindle, reducing vibration and runout. To upgrade a standard knob to one with a pilot, confirm that the pilot diameter is small enough to fit in your tool holder without touching the inner walls where the knob seats.