Available from Absolute Machine Tools, Zagar’s Precihole BTA deep-hole drilling machines are offered in four models with spindle powers of 22, 37, 71 or 115 kW. The machines are equipped with either FANUC or Siemens CNC controls. Models that hold the part stationary and feed the cutting tool are also available for applications where a high degree of concentricity is not required. The drilling machines are designed for major parts production in industries such as defense, oil and gas, hydraulics, automotive, general and heavy engineering, power generation, and nuclear energy, among others.
BTA drilling, or single tube system (STS) drilling, provides holemaking in the range of 1.00" to 12.00" ID for solid drilling and 16.00" for counter-boring with lengths ranging to 40 ft., the company says. The process drills holes into the centers of cylindrical parts, achieving high concentricity by rotating the cutting tool and feeding it into a counter-rotating tool. The tool is designed with carbide inserts and guide pads mounted to a toolholder drill tube. Coolant is introduced at a high pressure around the drill tube. The design is said to enable chip evacuation through the center of the drill and precise cutting efficiency.