When a steel ruler is used correctly. it can be used as an accurate measuring
instrument. The graduations are engraved and evenly divided to have a high
contrast to improve readability. The accuracy can be read to within 0.5mm.
The ruler is a straight edge that can be used in many industries. It is an
essential measuring device in the woodworking. machinist and technical
Some steel rulers have conversion tables and tap drill diameter tables on the
back that are indispensable.