... is researched and developed independently ZTR series rotary drilling rig is a track-retractable pile foundation pore-forming ... building groups.Main features of ZTR series rotary drill rig :1.Hydraulic retractable tracked chassis, auto lift, ... powerful horse-power.5.It can complete a set of short spiral bit, common drilling bucket, drilling bucket etc, ... whole process of moving parts. Rotary Drilling Rig