The idea of adding an angle 5 degrees past 90 is so that you can bend past 90 to allow for the spring back.
How to bend aluminum sheet metal.
When bending aluminum know that the smaller your inside bend radius the larger the chance that cracking will occur in the part.
If you re bending 0 020 thick material use a 0 020 radius.
As the lever goes down the anvil will descend pressing the punch pipe into the aluminum at the bend line.
Monkeys spinning monkeys by kevin macleod.
General advice on aluminum.
This in turn will cause the aluminum to conform to the angle of the notch in the v block.
Determine the angle at which you want to brake the metal and mark it on the protractor.
With the aid of a straight edge and a sharp knife score both sides of the aluminium sheet.
Then use your bend allowance to draw your second bend line the intervening distance between your bend lines bend radius.
Here s a good rule of thumb for most materials.
Sheet aluminium can be cut without the need for a guillotine or tin snips which tend to deform the metal.
Simple sheet metal bender using a hand roller clamps and plywood.
In other words if you re bending 1 8 sheet use a tool with a 1 8 radius to form the inside of the bend.
Cut the section of metal out or otherwise prepare the metal to be bent by removing any burrs or sharp edges.
When you release the handle the bent material will spring back to 90 not 85.
This weakens the aluminium and creates a fracture line.
Place the fracture line over the edge of a table and bend the overhang slightly downwards.
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.
Mark your bend lines.
Pull down on the lever to lower the anvil and bend the aluminum.
When you re done simply remove the piece and wipe off the bend line.
You will use the protractor to gauge the brake as you bend the metal little by little.