Hydraulic Chuck Drill Extensions Reach Past Fixtures

Kennametal’s line of hydraulic chuck (HC) extensions has been designed to enable drilling holes in deep cavities and complex pockets as well as reaching past clamps and fixtures. Key features include runout to within 3 microns (0.00012") at 2.5×D, improving tool life and hole quality; reduced vibration, even at 25,000 rpm, being balanced to ISO G2.5; and a hydraulic clamping mechanism within the chuck body. Internal channels facilitate through-the-tool coolant setup, without the need for hoses or adapters. A slim design enables clamping of, for example, a 12-mm drill in a 20-mm chuck body (or a ½" drill in a ¾" shank). A variety of reducer sleeves, available in both inch and metric sizes, provides cost-effective flexibility. Drill and reamer shanks down to 3 mm (0.125") can be accommodated. The extensions are suitable for rotating and stationary applications alike. 

The extensions do not require heat-shrink machines, thereby easing use. Tool lengths are adjustable up to 10 mm (0.393") axially. A specially-ground chamfer on the end of the shank eases insertion into the hydraulic chuck. Prepared wrench flats promote safe and convenient handling without the need for a torque wrench. A one-piece design minimizes concerns over contamination and downtime due to maintenance. The clamping mechanism eliminates operator-to-operator tightening variations, according to the company.

A simple design enables users to set any h6 tool shank inside the HC extension and turn the clamping screw on the end of the unit until seated. This causes a hydraulic piston within the unit to move forward, compressing the locating sleeve and gripping the tool.