... is 132kw, it can supply 260Kn thrusting and back pulling strength and 9000N.M torque, single time ... for the power head main shaft thrusting and back pulling, which greatly improves the working efficiency. ... heads: low speed in drilling in and pulling back work to guarantee the fluent construction. And under ... and uninstalling the drilling stem and go and back with no loading ,the power head will speed ...