Flat countersink square neck bolts

The head of the countersunk head square neck bolt, a 90 degree cone, is similar to the common countersunk head bolt, with tool tightening slots in the head in the form of a zigzag, cross, hexagonal, etc. On the surface of the mounting hole in the connection, a 90 degree conical nub is machined and the head of the countersunk square neck bolt is inside this nub, flush with the surface of the connection.