The table shows the minimum, optimus and maximum recommended punch widht (V), radius (R) and flap (B) for bending a steel sheet. This values could be different depending on the bending machine used for bending the sheet, but we can take them as reference values.
The table shows, for differents materials, the minimum engagement depth of a threaded hole (L) to enable the screw fails before the thread of the hole.
So, it is needed to define previously, the characteristics ot the screw:
– ISO Standard Thread (available from M1 to M36)
– Property class
– Thread pitch (fine or coarse)
Finally, the table also shows, the rest of dimensions that the hole should have, according to DIN 77 norm:
– Surplus thread length
– Thread total length
– Thread runout
– Hole total length
If the result of the cell is a “-” (dash), means that the holed material resistance is lower than the screw material, and in consequence, the thread of the hole will fail before the screw.