Precision straight-edges are typically made of hardened steel, but they can also be made of mild steel, aluminum, rigid plastic, stable wood, or other materials.
(Precision straight-edges; are made; of hardened steel; T:typically) (they; can also be made; of mild steel, aluminum, rigid plastic, stable wood, or other materials)
Precision straight-edges they
are made can also be made
of hardened steel T:typically
of mild steel, aluminum, rigid plastic, stable wood, or other materials