You will use the protractor to gauge the brake as you bend the metal little by little.
How to bend sheet metal at home.
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0 017453 x 90 x 0 020 0 33 x 0 024 0 0438558984 inch bend allowance keep in mind that some metals are more brittle than others.
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.
Otherwise the sheet metal is almost certain to shift as you bend it resulting in a bad bend.
Bending a brittle metal beyond its limits could cause the metal to snap and break.
Cut the section of metal out or otherwise prepare the metal to be bent by removing any burrs or sharp edges.
Clamping your sheet metal to the straightedge is a must.