ABS is made from acrylonitrile, butadiene, and styrene and is a type of plastic. The most important properties of ABS are its impact resistance and toughness.
Due to the properties listed above, and the fact it can be cheaply mass produced ABS plastic is an excellent material for a mitre box.
Mitre joints
A mitre joint is a joint made by cutting two objects (skirting boards for example) at precise angles. When the two pieces are joined together the result is a joint that fits neatly together.
The majority of mitre joints are made from cutting two lengths of wood at 45 degrees so that when joined together they form a precise and neat 90 degree angle. A skirting board would typically be cut in this manner to form a neat 90 degree joint in the corner of a room using a mitre box.
Mitre joints can be either internal or external. The internal mitre is on the inside corner of a wall and the external mitre is on the external corner of a wall.
Plywood
Plywood is made from several thin sheets of wood glued and pressed together to create a very sturdy and durable wood. Plywood can be susceptible to damp and can de-laminate when wet. Mitre boxes and mitre blocks are often made from laminated wood, but are generally considered a poor substitute for those made from beech.
Tufnol
Tufnol is a proprietary brand of laminated plastic material. Tufnol laminates are made from layers of paper, cotton cloth or glass fibre cloth which are dipped into a resin or varnish and then strongly bonded together under high pressure in a hot press.
Tufnol is used as a saw guide on skirting mitre boxes because of its hard wearing properties and smooth finish allowing the saw to cut smoothly and accurately.