Differences between nominal and actual widths can vary, and so specify the actual width you need.
Only along the baselines do townships have their nominal width from east to west.
Chainrings also come in several nominal widths:
The width of the slide rule is quoted in terms of the nominal width of the scales.
Such tires are designated with their nominal width and their nominal rim diameter, separated by a hyphen (-).
Rims are designated by their nominal rim diameter and their nominal width, separated by a cross (x).
Softwood with a nominal width of two to six inches is about half an inch less in actual width.
If the nominal width is greater than six inches, the actual width is less by about three-quarters of an inch.
Softwood having a nominal width of two through six inches actually measures about a half-inch narrower than the nominal dimension.
Differences between nominal and actual widths for hardwood can vary up to three-quarters of an inch for pieces wider than four inches.