Lock tool holders in place on CNC machines with a through-spindle coolant (TSC) system. They fit machines with a BT taper spindle. All meet industrial standards for tensile and shear strength. Also known as pull studs. These knobs have a pilot, which ensures precise alignment between the tool holder and spindle, reducing vibration and runout. 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. 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.

Use a torque wrench with a retention knob socket or a changeable-head torque wrench to tighten them.