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Squaring Shear

Squaring shears, like the one shown to the left, are used to cut sheet metal to a usable size. This shear is foot operated and can cut stock that is a maximum of 36 inches in width and 16-gauge in thickness. 

This sheet describes the procedure for cutting sheet metal stock to size. For other operations ask your instructor or refer to one of the many texts available.

Controls: The controls on the squaring shear located in the materials processing laboratory consist of the following:

  • A bed on which the stock will rest when being cut.
  • A foot pedal, which serves as a lever arm to amplify and transfer power provided by the operator to the cutting blades . 
  • A hold-down located at the rear edge of the bed to hold stock.
  • Side gauges located on both sides of the bed used to measure cut length.
  • Back gauges located at the rear of the shear also used to measure cut length. The back gauges also serve as a material stop when making repeated cuts of the same length.

Note:  There may be other controls on various accessories used with the shear that are not listed in this discussion.

Operation (shearing):  Shearing sheet metal stock to the desired length. The operator holds the stock in place and depresses the foot pedal to make the cut. Upon depressing the pedal the hold-down will secure the stock against the bed. Further depressing the pedal causes the blades to cut the stock with a shearing action. The shearing action is created by two blades, the lower blade remains stationary while the upper blade closes from right to left. Refer to the following illustrations.

  1.  Insure that the stock does not exceed the sheers cutting ability (maximum stock thickness 16-gauge).
  2. Clear the cutting table of any objects that may enter blade travel path.
  3. Inspect the shear to ensure that blades are secure and in good condition.
  4. Make sure the foot pedal travels up and down freely.
  5. Measure stock and mark the cutting point.
  6. Place stock flat on bed. 
  7. To insure a square cut, hold one side of stock against the adjacent side gauge.
  8. Hold stock firmly against bed and side gauge while making cut.
  9. Insure that fingers are kept clear of the blades and hold-down bar.
  10. Make sure area below foot pedal is clear.
  11. Depress foot pedal to make the cut.
  12. If cutting several pieces to the same length, set the back gauges to the desired length, then push stock against the back stop and make the cut.

Note: To learn about other methods of cutting sheet metal, consult with your instructor or shop supervisor. Do not attempt any operation that you are unfamiliar with.

Back Gages.  To adjust the backstop (green bar) loosen the yellow knobs and set the back gauges to the correct cutting length. Push stock against back stop while making cut.

Proper position for square cut. Stock must be held flat on bed and firmly against side gauge while making the cut. Keep fingers away from blades and hold-down bar.

Potential hazards: Because of the cutting power of the squaring shear, the following hazards exist.

  • Any body contact with the moving blade will cause severe injury. 
  • Contact with the edges of sheet metal may cause lacerations. 
  • Small pieces of metal can be thrown out at the operator. 
  • The motion of depressing and releasing the foot pedal may cause an injury.

Safety practices: Because of the above listed hazards the following safety rules must be followed.

  • Do not operate the squaring shear if you are unfamiliar or uncomfortable with its use.
  • Before cutting, insure the stock does not exceed the shear cutting capability (16-gauge maximum) .
  • Clear the cutting table of any objects that could enter the blades path.
  • Keep the floor and area around the shear clean and free from any tripping or slipping hazards.
  • Inspect the shear blades for defects and to insure that it properly secured.
  • Depress the foot pedal to insure it travels freely.
  • Always wear approved safety glasses.
  • Always wear gloves when handling sheet metal.
  • Never work alone.
  • Insure that foot pedal travel stops are in place and properly adjusted. Travel stops prevent the foot pedal from traveling to the floor and potentially crushing feet.
  • Remain focused on cut do not allow yourself to be distracted.
  • Hold stock firmly against side gauge while cutting.
  • Never cut stock that doesn't lay flat on the bed.
  • Use table extensions to control long stock.
  • Keep fingers away from blades and hold-down.
  • Remove any burrs caused by shears before further processing.
  • Treat cuts immediately.
  • Properly dispose of scrap material.

References:

Walker, John R., (1972). Exploring Metalworking. Goodheart - Wilcox. S. Holland, IL

Graham, Gregory S., (1981). Metal Working an Introduction. Breton Publishers. Boston, MA

ITT 252 - Materials Processing
Department of Technology
University of Southern Maine
Prepared by Steven Burgess, 11/15/2001