The double-thread heliks drills sneaked in with the single-thread auger suits the first floor to be the same, compares single-thread auger's structure difference to increase the another one side screw blade, caused the root leaf blade vertical spacing is smaller than 300mm, like this could in sneak in the process, maintained through the double headed the good stability and the explorative. Uses when this kind of drill bit carries on the rock layer construction, receives sneaks in the torque to grow, simultaneously the contact face were excessively many, reduced the drilling tool bit pressure.       

It is suitable for Bauer Germany or Sany Drilling machines!!