Presented by spm tools hydro pneumatic deep hole drilling head, model hpn 190/250 is a device which is used in drilling a hole whose depth is more than the drill diameter, retraction of the drill to clear the swarf is one of the effective ways. Wood-pecker cycle is specifically used for deep hole drilling. The spindle is moved backward ans forward by applying air pressure alternately to the two sides of a double acting piston. Duration of pecks is controlled by a torque sensor, which is sophisticated drilling technique. In case of a hard spot in the material or if the torque exceeds pre determined settings, the drill automatically withdraws. This evades breakage of expensive drills. Specifications: drill capacity - 12.5 mm in steel; max stroke - 190/250 mm; feed rate - steplessly variable, 0-300 mm/min; rapid traverse - 4 m/mm; drive - 0.75 kw motor; spindle speeds - max 4300 rpm, nin 480 rpm; thrust - 200 kg; and air supply 0.15 cmm at 5 kg/cm².
