Small-Diameter Coolant Drills

The CrazyDrill Cool line of coolant drills are designed for applications requiring deep, accurately drilled holes for very small diameters.


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The CrazyDrill Cool line of coolant drills are designed for applications requiring deep, accurately drilled holes for very small diameters. The drill's internal cooling system was developed to provide optimum cooling and lubrication at the cutting edge, even with low coolant pressure. The drill's cutting edge geometry is designed for optimum chip removal. According to the manufacturer, Mikron Corp. (Monroe, Connecticut), the drill can be run at speeds and feeds 10 to 20 times greater than what would be necessary for a standard deep-hole drill, and hole depths up to 10 times the diameter can be drilled in one pass without pecking.

These drills are available from stock in diameters from 1.0 to 4.0 mm (0.04 to 0.16 inch) in increments of 0.05 mm (0.002 inch) and in standard drill lengths of 6, 10 and 20 times the diameter. Intended to cover the entire spectrum of metals, the drill is available in an uncoated version for nonferrous applications and a coated version designed for heat-treated steels and in 366 standard sizes.

The manufacturer also offers a PilotDrill line for centering and drilling pilot holes, helping to hold tight tolerances in follow-up drilling with CrazyDrill drills. Diameter ranges and tolerances are matched to the CrazyDrill program. The pilot drills are designed to be particularly effective as a preparation to drilling holes more than 6 times the diameter in depth. As an example of the results achieved using a CrazyDrill in combination with a PilotDrill, Mikron cites the drilling of a 1.5 mm-diameter hole in stainless steel to a depth of 22.5 mm at a speed of 40 to 45 m/min and a feed of 0.05 mm per revolution. Only four pecks were required to reach the full depth of the hole.

In addition to the Cool line, the manufacturer offers CrazyDrill lines especially for steel and aluminum. The small-hole drills for steel are made of coated carbide and are available in 0.8- to 3.0-mm (0.03- to 0.12-inch) diameters in increments of 0.05 mm (0.002 inch) and drill lengths up to 7 times the diameter. The versions for aluminum are available in diameters from 0.4 to 3.0 mm (0.015 to 0.11 inch) in 0.05-mm (0.002-inch) increments and in drilling depths up to 10 times the diameter. Both are said to combine performance with longer tool life.


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