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Safety Handbook for Pipe Bender

STB-Series hydraulic pipe bender sets are designed to provide quick, safe, and wrinkle-free bending of schedule 40, 80, 160,and DEH pipe in 1⁄2'' through 4'' sizes. STB-Series pipe bender sets include the Enerpac hydraulic cylinder, hose, and manual, air, or electric powered pump. Sets are also available without hydraulics. The bending frame and shoes are lightweight, heat-treated aluminum. Eject-O-Matic™ series benders have double-acting cylinders to eject pipe from the bending shoe.

IMPORTANT: No bender set is all-purpose, please refer to selection chart located in the Enerpac catalog or the instructions included with the bender when selecting the proper bender to suit the size and schedule of the material to be bent. If in doubt, call Enerpac.


  1. Fully thread the hydraulic cylinder into the cylinder support block on the bending frame.
  2. Make sure that the saddle is fully threaded into the plunger fully hand tight.
  3. Make all hose connections between the cylinder and hydraulic pump. Make sure that the coupler(s) are fully hand tightened.
  4. Select the appropriate bending shoe for the pipe size. Each shoe is marked for size. An arrow indicates the center of the bend to be made.
  5. Insert and lock the bending shoe onto the cylinder plunger. Make sure to install the “U” shaped lock pin.


  1. On benders that are equipped with a single-acting cylinder, retract the plunger and remove the pipe from the shoe.
  2. On benders with double-acting cylinders, partially retract the cylinder. This will take any remaining force off of the pivot shoes and pins. Remove either one or both pivot shoes and reposition one pivot pin in the proper size “eject hole” where the pin will restrain the pipe, not the shoe, as they retract. Four-inch capacity frames have two “eject holes”. Use both sides.
  3. Now fully retract the cylinder plunger. The bending shoe and pipe will retract together until the pipe meets the pivot pin. On contact, the pipe will strip from the bending shoe.
  4. Remove the other pivot pin and pivot shoe to remove the pipe from the bender.
  • If the measured pipe diameter is greater than the maximum allowable diameter, do not attempt to bend that pipe. Attempting to bend oversized pipe could damage the bender and cause personal injury and will result in an unacceptable bend.


When activating the hydraulic pump, the operator must be located on the cylinder side of the bender. It is important to stay out of the line of force of the equipment while operating.

  • During the bending process, watch the optic gauge until the gauge indicating line for the designated angleis aligned with the mark on the
  • For complete bending instructions, refer to the instruction booklet included with every bender or call Enerpac.