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Big Kaiser has launched the HMCJ, a super-slim milling chuck with peripheral coolant supply, designed Thread Cutting Insert to support heavy-duty and finish-end-milling tasks with power and precision using ½"- or 12-mm-diameter cutters. The newest, slimmer member of the Hi-Power Milling Chuck (HMC) family features a clamping bore with fine slots surrounded by hundreds of needle bearings, which ensures concentric, precise and smooth clamping when the nut is tightened. The HMCJ provides high gripping force to the cutting tool shank, as much as five to six times greater than collet chucks, the company says.

The slim, yet rigid design of the chuck reduces the nut diameter to 1.260" (32 mm), the smallest in its class, Big Kaiser says. The chuck maintains a cross section of 0.394" (10 mm) to prevent chatter and promote cutting security. Carbide Inserts The maximum jet-through coolant pressure is 70 bar.

Despite being designed for heavy cutting, the HMCJ milling chuck can maintain a runout accuracy of 10 microns at 4×D, giving it additional flexibility for use on finishing applications. For additional rigidity and accuracy, the CAT and BT interfaces are Big Plus as standard, but a Big Plus spindle is said to be unnecessary to achieve performance with the chuck. A 32-mm, straight-shank design is also available.

It is also possible to use smaller-diameter milling tools through the use of PJC reduction collets. The 0.500"-diameter HMCJ can then accept 3/8" and ¼" shanks, and the 12-mm-diameter HMCJ can accept 10-, 8- and 6-mm shanks.