You will use the protractor to gauge the brake as you bend the metal little by little.
How to bend sheet metal at home.
Simple sheet metal bender using a hand roller clamps and plywood.
Otherwise the sheet metal is almost certain to shift as you bend it resulting in a bad bend.
Determine the angle at which you want to brake the metal and mark it on the protractor.
As an example if you want to bend 24 gauge sheet metal at a 90 angle the calculation would be.
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Clamping your sheet metal to the straightedge is a must.
To clamp efficiently lay your sheet metal on the top surface of your straightedge with the drawn line perfectly aligned with the outside edge of the sheet metal.
If the metal is still getting scratched up you can either put on a few layers of masking tape or use wood blocks like 2 4 s or something to sandwich the part for bending as you tap away on it with a mallet the wood will be soft enough to not damage the surface as long as there aren t any metal shavings hard things on it.