Introduction to Leather
Leather is unique...different than any cloth put together by man...for it is the actual skin of an animal that grew as the animal grew. To change this skin into leather, the skin must be tanned. Various methods of tanning produce leather for different purposes.
Leather for CARVING and TOOLING must be of "vegetable tannage". This tannage absorbs moisture readily...allowing it to be molded and formed easily...also carved, tooled, stamped and dyed or buffed to a high gloss. The skins of bovine animals (cows, oxen, etc.) provide most of the leather for carving. This leather is commonly called "STRAP" leather.
The skin is a full hide as it comes from the animal. Smaller animals (calf, goat, sheep, pig) are usually tanned as a skin or full hide. But for easier handling during tanning, large animal hides (cows, buffalo, horses, etc.) are usually cut in half at the backbone. Thus, a side of leather is just that!! It is one side or one half of a hide.
Unlike cloth which is manufactured, leather, grown by nature, is less uniform in grade and thickness. Therefore, it is not unusual for a given leather in a given grade to vary slightly from time to time.
The THICKNESS (or weight) of leather is usually measured in terms of ounces. One ounce equals approximately 1/64" in thickness. Thus, 7-8 oz. means the leather is 7 to 8 oz. in weight or 7/64" to 8/64"...meaning approximately 1/8" thick. One square foot of 7-8 oz. leather should weigh 7-8 oz. Lighter weight leathers such as calf or kip (large calf) range from 1 1/2 oz. to 3-4 oz. Heavier leathers, 4-5 oz. to 10-11 oz. and more come from the hides of mature animals.
To make leather a uniform thickness, the hides are run through a splitting machine. Since animal hides are not of uniform thickness and since they are wet when put through the splitting machine, the thickness of the leather will not remain the same throughout the hide. There will always be slight variations and that's why leather weights seldom measure out in exact 64th's of an inch. This is why leathers are usually shown a 4-5 oz., 6-7 oz. etc.
The "flesh" side of leather is the underpart that was next to the meat and flesh of the animal. The hair side, called the "Grain" side, is most commonly used for carving and tooling. It's fiber structure is more closely knit and easier to cut with the swivel knife. When carving and stamping tools are properly used, the Grain side will retain even the tiniest details.
The Grain side has a "grain layer" of about 1/5 the thickness of the hide. The rest of the hide consists of a honeycomb fibrous structure that works like interlacing hinges or scales. During tanning fats and oils are added to this honeycomb structure to make the grain side leather soft and workable.
It's interesting to note that...No animal or reptile produces both "fur" and "leather". It's one or the other, but never both. The "fur bearing seal" and the seal from which leather is tanned are two entirely different species.
Page content updated 01:44:14 2005-04-13
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