Fastener with a modified thread form

Claim 1

In combination a double-ended stud having a first thread configuration on one end for tapping into relatively soft material and a second cylindrical thread configuration on the other end, an internally threaded nut cooperatively adapted to engage said second thread configuration in order to secure said soft material to a base member, said two thread configurations being separated by a laterally extending flange, said second thread configuration having a first series of thread convolutions of a predetermined axial extent and which mate with and have normal full engagement with, the internal thread of said nut, said nut having a washer associated therewith, said first series of thread convolutions predetermined axial extent being defined by a distance extending axially along said second stud end to a point which is spaced from said flange a distance which is not greater than the sum of the height of the nut plus the thickness of said washer plus the thickness of said base member, a second series of thread convolutions in excess of one thread turn in said second thread configuration and positioned along said second stud end at an axial location which is farther from said flange than said first series of thread convolutions, said second series of convolutions having a thread diameter which is less than that of said first convolutions but of a diameter which will still provide partial engagement with the internal thread of the nut whereby, when the nut is removed from the second stud end, the reduced diameter of said second series of convolutions will provide substantially circumferentially continuous clearance for paint particles and the like, so as to avoid loosening of said first stud end in said comparatively soft material.