Page 233 - Demo

231DEEP HOLE DRILLING%u00bd%u0009BTA System STSThe BTA system (Boring and Trepanning Association), also called STS (Single Tube System), is a modified deep hole drilling method that was developed in the 1940s to minimize the disadvantages of the SBL system (gundrilling) such as chip contact with the hole surface and low torsional moment. The BTA system got its name in the 1950s. The development of the BTA system was dominated by the German company %u201cGebr%u00fcder Heller%u201d, which during the second world war combined its own developments with the developments of Burgsm%u00fcller and Beisner. Burgsm%u00fcller replaced the previously used grooved drill shaft with a tube and for the first time the chips were evacuated through the inside of the tube. Beisner improved the drill design and introduced oil as coolant.Gebr%u00fcder Heller has introduced carbide cutting edges and guide pads into the BTA system.The BTA system covers the largest range of drilling diameters in comparison with other systems (ELB and DTS). ISCAR provides BTA drills for drilling holes with an inner diameter of 8 mm to 294 mm and a depth of up to 325 drill diameters.