Square Thread Standard: Dimensions, Form and When to Specify – IsoCNC

Square threads carry high axial loads with low friction because the thread flank is perpendicular to the axis – the reason they dominate screw jacks, press screws and valve stems. This IsoCNC guide covers the ACME-style square thread proportions (pitch, depth, flat widths), the clearance needed for assembly, machining notes for single-point threading, and how square threads compare with ACME and trapezoidal forms when specifying a custom machined screw. IsoCNC machines these parts to print from bar stock or forgings.