Minimum thread engagement depth
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.