British Leatherwork and the metric system - leather tutorial

British leatherworkers live in a very strange and uncoordinated world. We buy English (and a significant amount of continental) leather by the square foot and by millimeter thickness. 

The reason for the square footage is often because the tannery that makes the leather measures it using an old (sometimes 80 to 100 years old) machine that was built to use Imperial measurements. A new metric measuring machine would cost so much that it isn't worth considering until the old one breaks down and is impossible to repair. This could be a while because they are generally built like armoured cars. Amusingly, quite a bit of Italian leather is imported by the square metre and then sold by the square foot because British leather workers prefer it!

Millimeter thickness is explained by the import of a large number of relatively inexpensive Italian made thickness guages with metric gradations. These were a cost effective replacement for the worn Imperial thickness guages that had been in use since Victorian times.

The American system is even more confusing as leather thickness is usually measured in ounces. One ounce equals 1/64" in thickness. This means a weight of 4-5 ounces is actually 1/16" to 5/64" in thickness. GIven that the thickness of a hide can vary considerably across its surface, this can be quite confusing for British leatherworkers buying from American companies like Tandy and apparently a lot of Americans struggle with it too. American hides are often sold as being 4-5 oz or 6-7 oz to accomodate the variations in thickness.

If you work in the shoe industry you may also come across irons being used as a measurement of thickness. This is an antiquated British system of measurement that only confuses an already complicated system. I don't think I have ever used irons as a measuring system, but it is worth adding here as a 'nod' to the past.

The very best leatherworking tools (IMHO) are the old British ones made from high quality steel; unfortunately they were generally made to accomodate Imperial measurements. I should add that early American tools are often extremely good and are also Imperial. New tools from America are generally made with Imperial measurements but tools from Continental Europe, China and Japan are often sold with metric gradations.Nobody said this stuff was easy...

Machinery from Italy, France and Germany is invariably in metric whilst old British machines and new American machinery is almost always made with Imperial gradations.

Solid brass buckles are usually sold in Imperial sizes in the UK and America but continental buckles are often only available in metric sizes. Tricky if you (like me) have a workshop full of old British tools and machinery.

Nobody says it makes sense, it just happens to be the way the leatherworking business works. Live with it!