When bending aluminum know that the smaller your inside bend radius the larger the chance that cracking will occur in the part.
How to bend aluminum sheet metal.
Cut the section of metal out or otherwise prepare the metal to be bent by removing any burrs or sharp edges.
Simple sheet metal bender using a hand roller clamps and plywood.
As the lever goes down the anvil will descend pressing the punch pipe into the aluminum at the bend line.
This weakens the aluminium and creates a fracture line.
The idea of adding an angle 5 degrees past 90 is so that you can bend past 90 to allow for the spring back.
Then use your bend allowance to draw your second bend line the intervening distance between your bend lines bend radius.
The inside bend radius should be equal to the thickness of the material that you re forming.
This in turn will cause the aluminum to conform to the angle of the notch in the v block.
Now that you know your bend allowance take your protractor and draw a clear line with your marker across the point at which you will bend your sheet metal.
Mark your bend lines.
When you re done simply remove the piece and wipe off the bend line.
Sheet aluminium can be cut without the need for a guillotine or tin snips which tend to deform the metal.
If you re bending 0 020 thick material use a 0 020 radius.
You will use the protractor to gauge the brake as you bend the metal little by little.
Determine the angle at which you want to brake the metal and mark it on the protractor.
Place the fracture line over the edge of a table and bend the overhang slightly downwards.
With the aid of a straight edge and a sharp knife score both sides of the aluminium sheet.
I used a angle of 5 degrees this is because when you bend the metal you usually want 90 degrees and when you hit 90 the metal will want to spring back a little.
When you release the handle the bent material will spring back to 90 not 85.
General advice on aluminum.
Monkeys spinning monkeys by kevin macleod.
Also know that for the best results and fewer cracks on the outside of the bend the bend line should go across or diagonal to the material grain when and where possible.