Abstract: A fastener with a modified thread form discourages a nut from becoming irremovably frozen on the shank of a bolt. A first normal thread extends from a base reference surface to a height on the fastener shank to permit full thread engagement by a nut. Axially outwardly along the shank from that point, there is provided a second thread of reduced crest diameter but still of sufficient size to engage the threads on the nut. This reduction in thread diameter provides additional clearance to permit the nut to be backed off in spite of marred threads or paint or rust buildups.

Abstract: An orthodontic screw-type biassing device comprises: a first member having an internally threaded bore, the threaded bore comprising first and second threaded portions adjacent each other in the axial direction of the bore, the first and second threaded portions having thread roots which lie substantially on a common line, the first threaded portion having threads of given depth and the second threaded portion having threads of a lesser depth. A threaded inner screw-type member is threadably engaged in the internally threaded bore of the member, the threads at an end portion of the inner screw member being deformed so as to freely, threadably pass through the second threaded portion of the threaded bore and to bind and be non-rotatable in the first threaded portion of said threaded bore. The invention is also directed to a method of making such a biassing device.

Abstract: A threaded insert and method for making same which is particularly usable when fixedly positioned within a base material which itself is molded about the threaded insert, the threaded insert comprising a generally cylindrical body which is preferably knurled about the exterior thereof to provide a means for fixed securement between the insert and the surrounding base material, the cylindrical body including a central bore extending part way or completely through the insert, the central bore being threaded such that each individual thread includes a burnished end thereof such as to provide an arcuate surface immediately adjacent the mold or immediately adjacent the pin extending through the central bore to prevent the seepage of base material when under pressure during molding past the threads to foul the threads by having base material therein, the dimension of the burnishing on the tips of the threads being of such small dimension that the first placement of a threaded male member into the threaded central b