The calculator uses the formula:
ΔL=L·α·ΔT
If is needed to calculate another material that is not included in the table, the calculator has a row (Other material) where the user can introduce the new linear temperature expansion coefficient (α).
Countersink for DIN 7991, DIN 7987, DIN 7988, DIN 87, DIN 88, DIN 7513, DIN 7516
DIN 75
FORM B
This Calculator provides the values of the countersink for next countersunk head screws :
DIN 87, form B
DIN 7987, form B
DIN 7991, form B
DIN 88, form B
DIN 7988, form B
DIN 7514 , form D and E from M6
DIN 7516, form B and C
Countersink for DIN 912
DIN 75
Countersink for DIN 84
DIN 75
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.