System BTA Overview Solid drilling tools with brazed carbide inserts & guide pads with indexable inserts and guide pads Counterboring tools with indexable inserts and guide pads Trepanning with indexable inserts and guide pads Accessories drill tubes connecting chucks vibration damper pressure heads drill bushings spare parts adaptors tool presetter	Type 28 - trepanning head. 1-start internal connection thread diameter range: 55.00 - 197.99 mm Type 48 - trepanning head 4-start external connection thread diameter range: 55.00 - 197.99 mm with flange mount diameter range: 198.00 - 412.99 mm