About the Tool: Bends sheet of metal to create a rounded corner based on the physical setup used.
Location: Machine Shop, Room 114
Access: Sheet Metal Bender training required. Visit the Machine Shop to request training.
Materials: Sheet metals
Accuracy: Accuracy varies.

Design Considerations


  • Ideal world
  • Sharp, clean defined corners



  • Real World
  • Rounded, approximate corners.

Depending on your design you may have different dimensions that are critical.

Some key dimensions may be:

  • External length and width
  • Internal length and width
  • Internal Radius of Corners
    • This radius can be equal to or greater than the minimum radius the material can obtain when bending. More on this is given in the Bend Allowance section below.

After choosing the proper dimensions you can use algebra to solve for the others.

Bend allowances are the length of sheet metal required to preform a bend. 

Require variables

How to find the bend allowance

You can determine this allowance in a few ways.

  1. Bend Allowance Calculator
  2. You can approximate it with the minimum radius provided in the Inner Radius Dimensions Chart for different material gauges (thicknesses)

After determining the lengths of the sides you want and the bending allowances you need in order to create your bend, make the appropriate markings on the sheet metal. Before moving on to bending look at the markings and double check that everything seems to be in the right place. 

Physical Setup

  • Mark beginning and end of bend allowances on part before starting.

  • Line up beginning of bend allowance with separation in metal bending platform.

  • Line up end of bend allowance with clamp. Add C clamps to keep part secure.



  • Put levers in place.

  • Pull toward you to complete the bend (this may require another person to help complete).

Safe Operation

  • Work with pieces that have already be deburred.
  • If bending allowance used is too small the clamps can slip or the piece can break.
  • Ask for help if you cannot perform bend alone.


  • Unclamp and remove workpiece
  • Put C clamps back
  • Place bar clamp back on meta bender platform