DIN 439 Metric Thin Hexagon Nuts. Standard Pitch. Various Materials and sizes

Din 439 is the standard for thin Hexagon nuts with metric coarse and fine pitch thread. Often also called half nuts, lock nuts or jam nuts. 

Although the standard has now been withdrawn it is still very widely used. And is very similar to the  new standards EN ISO 4035 

These are usually used as a lock nut, where it is threaded up against a standard nut locking it into place. Can also be used in circumstances where a standard nut is too thick

DIN 439 Specifications 

As you will see from the table below these 'half nuts' have a thickness of 0.5 * Diameter. So an M10 threaded half nut would have a thickness of 5 mm

All of the nuts are standard thread pitch (sometimes called coarse)

Please note that the galvanised nuts are tapped oversize to allow for the layer of galvanising

All measurements in millimetres (mm)

All these dimensions (and others) in the DIN standards do have manufacturing tolerances accurately defined. They can be downloaded at the relevant standards websites. This data is purely informative

Materials:

A4 (T316) Marine grade stainless steel has a greater corrosion resistance than A2 in certain environments. It is often used for Marine applications especially when coming into direct contact with saltwater.

A2 (T304) stainless steel has good resistance to corrosion except in severe industrial and Marine conditions. Use A4 in a marine environment.

BZP - Bright Zinc Plated - A 3-micron plating is applied to the steel to give a shiny finish. Although it does afford some protection this is best suited to indoor use.

Galvanised - A duller finish than BZP, typically 50 microns thick covering of Zinc and therefore provides much more protection suitable for many outdoor applications. To allow for this layer you should use tapped oversized nuts