Hydraulic Rotary Cylinders are suitable for operating Hydraulic Chuck or Collets. This cylinder is mounted on the back side of Lathe spindle and it operates the chuck or collet through a draw bar attached with piston rod of cylinder. A non-contacting type rotary joint is provided with cylinder which is free from maintenance. This joint gives certain amount of oil-leakage for which one outlet is provided. Cylinder is mounted in horizontal position.