# What is a F spanner?

## What is a F spanner?

On UNF, UNC and Metric the measurement of the spanner is said to be A/F or across flats. This means that the actual size of the bolt head is the measurement of the spanner. So that a 1/2in A/F spanner will fit a bolt head of UNF, UNC which will measure 1/2in.

## What is a 17 spanner?

A 17mm spanner therefore fits a nut 17mm across its flats and this is normally a nut to fit a 10mm diameter bolt (M10). Also, hexagonal key sizes are given as the distance across their flats and so a M10 Allen Screw for example would need a 8mm key to fit it.

What does spanner number mean?

The number given on spanner is outer diameter of Nut and bolt in MM.

What are af sizes?

Imperial and Metric Spanner Sizes

BOLT DIAMETER (INCHES) AF SPANNER SIZE (INCHES) SPANNER SIZE (MM)
3/8 INCH 9.52 MM
1/4 INCH 7/16 INCH 11.11 MM
5/16 INCH 1/2 INCH 12.7 MM
3/8 INCH 9/16 INCH 14.29 MM

### What does AF stand for in spanner size?

The term width across flats (AF) is used for the following forms: 2-socket = round material with two surfaces. 4-socket = profile square section. 6-socket, 8-square = regular polygons.

### What size is a 17 spanner?

Metric Spanner Sizes

Nominal Size Spanner Size
M10 17mm
M12 19mm
M14 22mm
M16 24MM

What size bolt fits a 17mm socket?

Metric Fasteners – Wrench size needed for Driving common Nuts
Screw Size Wrench Size * Alt Size, Flange Nuts **
M6 10mm 10mm
M8 13mm 13mm
M10 17mm 15mm

How do you measure spanner size?

Spanner. The width across flats indicates the nominal “size” of the spanner. It is imprinted on the spanners in millimeter (mm) values.

#### What does F mean on a bolt?

In reference to fasteners DIN indicates fasteners that conform to a specific metric standard (will be followed by the standard number). F. Fully Threaded.

#### What is a F in bolt?

A/F (measurement) Across The Flats: 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.

Is AF same as imperial?

Imperial are another range of sizes completely;tend to be found on older UK vehicles. Most people take imperial to be inch sizes which are AF. If you’re thinking of Whitworth then you’ll struggle to get a whit set for cheap money these days. Most AF sizes are useful for when the metric nut is rounded etc.

What does NF stand for on bolts?