Why is a die stick rotated 1/4 turn back for each 1/2 forward turn when cutting threads in a rod?

When cutting threads on a rod, rotating the die stick 1/4 turn back for each 1/2 forward turn serves an important practical purpose related to the management of chips. As the die cuts into the material, it produces metal shavings or chips that can accumulate in the cutting area. If these chips are not effectively managed, they can cause the cutting tool to bind, leading to an uneven cut and potentially damaging both the tool and the workpiece.

By reversing the die slightly, it helps to break and clear the chips from the cutting area, preventing buildup that could hinder the threading process. This technique ensures that the cutting action remains consistent and smooth, allowing for cleanly cut threads. Thus, the practice is fundamentally about enhancing the efficiency of the cutting operation and maintaining the quality of the threads being produced.