Squeezing under reamer is commonly used in pile drilling. It works by the hydraulic power from the, and can enlarge the drilling hole during the drilling job.

It includes control system, rotation device, hydraulic hoses, squeezing cylinder and drilling bucket. the reamer's three retractable cutting arms are opened and held in position by continuous hydraulic pressure. Cutters are retracted by disengaging the pump, allowing the tool to be re-positioned for selective under reaming operations or retrieval from the hole. A piston spring assists with arm retraction following interruption of hydraulic pressure.

this under reamer can finish the jobs as drilling-squeezing-cleaning, and can work continuously. as it is rotating squeezing, the hole is very integrated thus warranty the quality of construction.