BIG Kaiser’s Hi-Power Milling Chucks (HMC) achieve powerful clamping and high rigidity for heavy cutting applications. The unique slit design means that the new HMC12J applies the highest gripping force to the cutting tool of any comparable chuck in its class. Due to the inherently stronger construction of milling chucks, the clamping force of these chucks is five to six times greater than standard collet chucks, it is claimed.

The chuck design integrates fine slots and hundreds of needle bearings to ensure precision high power clamping performance, while also offering 10 microns at a 4xD runout, which makes it suited to finishing applications, too. The unit’s external diameter is 32 mm, the smallest in its class, and the chuck can be used on machining centres with conventional spindles.

In a test, the new HMC12J was compared to a collet chuck. Operating on a DMG Mori NVX 5080 milling machine with a BIG-Plus BBT40 spindle system, the trial milled C50 steel with a 12 mm diameter cutting tool. Conditions were set at V=80 m/min, feed per tooth (fz)=0.092 mm, width of cut (ae)=3.5 mm. From this, the depth of cut (ap) was increased until vibration was evident. The result was that the HMC12J could cut to a depth of 22 mm before vibration was experienced, which was double the 11 mm cutting depth achieved with the collet chuck.