Automotive Dictionary: A/F (measurement) Across The Flats
Throughout this site we use many technical terms, and given the breadth of readership our site enjoys, sometimes we are remiss and incorrectly assume everyone knows what we are referring to. For those that do not, here are some explanations of the technical terms use.
A/F (measurement) Across The Flats:
Widely-used system of measuring nut sizes. Nuts and bolt-heads are measured by the distance between the jaws, or flats, of the spanner needed to turn them. This is an alternative method to that of measuring the thread size of the bolt. It is usually quoted as, for example, 7/8" A/F.