A wool bale is a standard sized nylon wool pack of wool compressed by the mechanical means of a wool press. This is the regulation required method of packaging for wool, to keep it uncontaminated and readily identifiable. A "bale of wool" is also the term of reference for a container of raw wool, much in the same way that "gallon of oil" is the term of reference for crude oil.
Wool has been pressed into bales for many years and has been transported by camel, horse or bullock wagons, rail, boats and later by trucks.
The wool presser takes the wool from the wool bin and presses it into wool bales. Very early wool presses were primitive affairs made from wood boards and had a wire winch mechanism to compress the wool and also hollow logs where the wool was tramped into a pack. During the late 1800's various forms of the Koertz wooden wool press became the standard. There were also the steel Ajax wool presses, too. Nowadays power operated, self pinning wool presses with inbuilt scales have made a major contribution to shearing shed productivity.
It takes about 60 skirted fleeces to fill a wool bale, depending on the size and age of the sheep. The presser closes the bale with eight metal bale fasteners, before weighing the bale, if the press does not have an inbuilt scale. Bales should weigh between 110 kg and 204 kg, unless the wool is under 18.6 microns, in which case they may be a minimum gross weight of 90 kg. The presser is respondsible for completing the wool book and then branding the bale with the owner's brand, contents description, number and wool classer ID.
After the wool is sold at auction bales are usually dumped i.e. pressed to a higher density, still in the original wool pack, for shipment to overseas mills. Three bales that have been dumped and tied with a metal band are known as a tri pack.
Learn about wool fibers.
Bradford System (wool measuring)