How to Bend Sheet Metal

A machine shop bends metal with a monster called a "break," in the same way that you bend a piece of cardboard over a table edge to get a bend along a straight line. The difference is that the break exerts tons of pressure uniformly along the line where you want the metal to bend, which you cannot do with a pair of pliers. If you need to bend sheet metal yourself and don't have access to a machine shop you will need to find a solution. The answer? Build a homemade break.

Things You'll Need

• 2 pieces of angle iron, each longer than the width of the largest piece of sheet metal you plan to bend
• Stable workbench, preferably the one built into your shop
• Drill and bits to drill through the angle iron
• 8 wood screws, to attach 2x4 lumber to angle iron
• 3 round head 5/8" bolts and nuts
• 3 industrial door hinges, with screws for the hinges
• 4 pieces of 2x4 lumber, the length of the angle iron
• 1 piece of 2x4 lumber, 24" in length
• 2 wide jaw locking pliers

Instructions

How to Bend Sheet Metal

1. Drill holes every 12" through one side of each piece of angle iron, through 2 of the 2x4s, and through the front edge of your workbench, as shown.
   Use the drilled angle irons to mark the holes on the lumber, as the the angle irons will be fastened to the 2x4s.

2. Bolt one angle iron to your workbench with the drilled lumber behind it as a spacer, as shown.
   The spacer will allow you to bend the metal to slightly more than 90 degrees, to compensate for "spring back" in the bend.

3. Attach the 24" long piece of 2x4 lumber to the middle of the second drilled piece of lumber to form a handle. Attach the second angle iron to the second drilled piece of lumber, as shown.
   Be sure that the angle iron is at the edge of the lumber, as shown.

4. Bolt one side of each of 4 of the hinges onto the angle iron as shown and the other side of each hinge to the top of your workbench, as shown.

5. 

   To bend metal, insert the metal from the bottom so that the place where you want the bend to be is at the edge of the angle iron attached to your workbench, as shown. Clamp the metal. Pull the handle in the direction show to bring the the hinged piece of lumber and angle iron down. As you pull the handle, the metal will bend along the line formed by the two pieces of angle iron.

Tips & Warnings

• Remember the carpenter's advice: measure twice, cut once? Now you can measure twice and bend once. Any size angle iron works, but 1" is the optimal size.

• Sheet metal has very sharp edges; wear Kevlar gloves specially designed to prevent cuts.

Resources

• Another Version of the Homemade Break