Bending

Unfolding : 

external dimensions -2 x thickness

Size of the folding V:

6 to 8 times thickness
6 x for steel
8 x for  the stainless steel and beyond 6mm thick.
Example: S235 steel 2 mm thick
2 x 6 = 12 mm

Minimum length of fold
For a 90 ° angle, it is the width of the V x 0.75

exemple:  for 2mm 6 X 2 X 0.75 = 9mm