Flat Head Machine Screws
Flat head machine screws have a countersunk head with a flat top surface and a cone-shaped bearing surface with either an 82 degree or 100 degree head angle. Flat undercut is similar to an 82 degree flat head except that the head is undercut 70% of its normal head height. Flat head machine screws are used in applications where protrusion of the screw above the mating surface is not wanted.