Brochure

7
Subject to change without notice. Please refer to your local Bossard E-Shop for the current assortment and dimensions.
Other variants upon request.
Application Guidelines
Thread-forming displaces material, thus a small
bulge is produced at the hole’s entrance. This may
prevent parts from being tightly fastened. A 90º
chamfer, with a depth of 0.5 to 1 x the thread pitch,
will avert that. A shallow relief bore will do the same.
By putting a relief bore at the entrance of the pilot
hole, the thread engagement of the individual
assembled parts can be kept constant. This way,
driving torques can be kept the same, assuming the
screw diameter and material are the same. In thin
sheet metals an extruded hole will increase pull-out
force. Thread-forming screws are highly vibration
resistant.
Screw installation without countersink (small bulge)
Relief bore
Extruded hole
With countersinking, screw not yet installed