A thread repair tool for rethreading a blind tapped hole having damaged threads above undamaged threads of the hole, including: a shaft having a plurality of curved surfaces that extend from a top end of the shaft to a bottom end of the shaft, the plurality of curved surfaces being concave with respect to an exterior perimeter of the shaft; and wherein the shaft has a plurality of corner portions, each one of the plurality of corner portions being located in between two of the plurality of curved surfaces, a first pair of the plurality of corner portions extending from the top end to the bottom end, and a second pair of the plurality of corner portions having a threaded area proximate to the bottom end, the first pair of the plurality of corner portions being adjacent to each other and the second pair of the plurality of corner portions being adjacent to each other.

The compound die includes a working surface with a coarse end for forming coarse threads and a fine end for forming fine threads. The coarse end has coarse crests and coarse roots thereon angled at a coarse thread pitch angle for the screw to be formed. The fine end has fine crests and fine roots formed into a working surface thereof at an angle matching a pitch angle for the fine threads of the screw to be formed. A transition is provided between the coarse end and fine end where each of the coarse roots is aligned with one of the fine roots. A screw such as a bolt is roll formed by first being rolled between a standard die parallel with the compound die and a course end of the compound die, followed by rolling between the standard die and the fine end of the compound die.

A thread repair tool for rethreading a blind tapped hole having damaged threads above undamaged threads of the hole, including: a shaft having a plurality of curved surfaces that extend from a top end of the shaft to a bottom end of the shaft, the plurality of curved surfaces being concave with respect to an exterior perimeter of the shaft; and wherein the shaft has a plurality of corner portions, each one of the plurality of corner portions being located in between two of the plurality of curved surfaces, a first pair of the plurality of corner portions extending from the top end to the bottom end, and a second pair of the plurality of corner portions having a threaded area proximate to the bottom end, the first pair of the plurality of corner portions being adjacent to each other and the second pair of the plurality of corner portions being adjacent to each other.