About Leather - A Short Guide

Leather was once the skin of a living animal. Although treated by a tanner to preserve it, soften -or harden- it, a hide may still display variable properties depending upon where it lay on the animal. The drawing on the left shows the sections of a trimmed cow hide as offered for sale by a typical tanner. Cow hide is most commonly used for hand work. The characteristics of each section are also shown. Get to know these before purchasing hides for specific jobs.

The Back

Sometimes referred to as a Harness or Bridle Back; this is the butt and shoulder area taken as one piece with the bellies removed. The back is often divided into two sides to reduce cost of purchase. The leather nearest the butt and spine is the best on the hide. This cut is best used for belts, boxes and harness as it has the potential for the longest cuts.

The Butt

This is the best cut on the hide. It has the tightest structure and is thicker and stronger than other parts. The weak belly and coarse shoulder pieces are removed. Often sold as pairs.

The Shoulder

This has a softer, less even structure than the butt and can display uneven grain in places. This is often used to advantage when making bags and cases. The thickness is too variable for belts.

The Side

This a hide cut in half and usually includes the belly. Quite a large cut but one that offers the full range of textures and qualities from a hide and therefore can be used in most work.

The Belly

This is very stretchy, has a loose structure and variable thickness. It is a cheap cut though, and useful for practise work or small items such as key fobs etc. Can also be used for backing or lining.

Tanning

Leather has a complicated structure that is used by tanners to derive material suitable for all types of task. Tanning renders the skin stable and rot proof whilst retaining its structure and strength. The process involves several stages; removal of hair and epidermis (the very outer layer) and also of the fatty part of the flesh. The remaining layer is called the corium. The corium is stabilised by one of several methods using animal oils, alum, chrome salts or vegetable tanning.

Chrome tanning involves tumbling skins in drums with chromium salts and other chemicals. It is very quick and the most common method in use today.
Vegetable tanning is a more traditional method and takes somewhat longer to achieve results. It can take up to one year for hard leathers. The hides are hung or laid flat in a series of pits which contain a liquor composed of water, tree barks -oak is common- and leaves. The ingredients are chosen to give varying results depending upon the desired type of leather, and the liquor increases in strength as the hides go through the factory. It is this leather which is most suited to hand work. Some hides are also brushed to remove blemishes and growth marks, this imparts a slightly pink colour.

Hide thickness and sizes

It is now usual for hide thickness to be measured in millimetres and size to be measured in square metres, but be prepared to deal in square feet as well.