These straight edges are precision ground and nicely finished to rigid Starrett standards.
Benefiting from the density and strength of tooled steel, these rulers are heavy and stay right where they are placed, and provide the most accurate surface to cut or tear paper against.
They also will not nick or be shaved down when running knives against them as softer aluminum rules do. They are unexcelled for drawing or scribing straight lines, tearing paper with, and checking surfaces for straightness. Their thickness and design permit them to retain shape and accuracy, but still be portable and easy to handle.
The Starrett rules are our heaviest rules, machined from tooled steel with one straight edge and one beveled. Edge straightness .0002" per foot. Parallelism .0004" per foot.
The Lengths and X-Sections for each below: