from The Century Dictionary.
- Having a thread with a rectangular section instead of the more usual triangular or sharp thread: said of a screw. The helical projection is formed by revolving a rectangle or square around a cylinder, and causing it to advance in one complete revolution a distance equal to the pitch parallel to the axis.
Sorry, no etymologies found.
As the curves _f_ above the line are the same as _f_ below the line, the template for _f_ need not be made to extend the whole distance across, but one-half only; as is shown by the dotted curve _g_, in the construction for finding the curve for square-threaded nuts in Figure 212.
In the case of square-threaded screws being required, a square-pointed tool was employed in place of the V or angle-threaded tool.
a square-threaded worm, the length of which and the distance which it enters the barrel of the baffler determining the amount of flow.