The balancing a toolholder plays a vital role ti enhance its body's mass distribution to achieve rotation above the prescribed limit without creating any centrifugal forces. Toprun toolholders are used for high speed machining. The device significantly extends the machine's center spindle life and tool life with enhanced accuracy and surface finish. The machining center witnesses a drastic reduction of vibration and noise level. The two counterweights in the graduated groove (patented) are positioned as per the indications on the electronic balancing unit to quickly and easily balance the toolholder fitted with tie-rod and tool as per ISO?1940/1 standard. The counterweights can be positioned at 0° and at 180° for machining up to 8,000 rpm.