Strength of materials used

Ease of insertion when nailing

A well degreased nail is more difficult to drive than a lightly oiled nail. It is therefore not desirable to clean and polish nails completely after manufacture.
Because of its gimlet effect, a helical thread shank facilitates driving into hard or wet woods and reduces the risk of splitting.
An annular ring shank has to break the fibres of the wood when being driven and is therefore specially resistant to pulling but care must be taken to use proportionately thinner gauges than with other shanks.

Strength of materials used

Materials used in the manufacture of nails and hooks exhibit important differences in elasticity and breaking stress. 

The following measurements were made on the wires used:
Aluminium	310N/mm²
Stainless steel	700 à 800 N/mm²
Copper	360 à 400 N/mm²
Steel	650 à 750 N/mm²

The strain hardening caused by the manufacturing techniques increases the hardness value of the finished nails.

 

Notching, and particularly annular rings, improve the hardness to prevent bending, especially when being driven into hard woods.

 

However, when using aluminium, it is important only to use the lightest materials and to increase the gauge to ensure optimum results.

 

In the same way, each groove of the annular rings is a breaking point and consequently the gauge of stainless steel nails weakened by ringing should not be reduced too much. This does not apply to copper which has remarkable elastic properties and is not likely to break at the annular rings.