Your Daily Facts about Plywood
Plywood is a manufactured wood, made by gluing together a number of thin veneers or plies of softwood or hardwood. It is used mostly in commercial sites, purely because it is a strong durable substance. A common reason for using plywood instead of plain wood is its resistance to cracking, shrinkage, twisting/warping, and its general high degree of strength. Also, plywood can be manufactured in sheets far wider than the trees from which it was made. It has replaced many dimensional lumbers on construction applications for these reasons.
Manufactured panel made up of three or more thin plies (layers) of wood. Each ply is laid down with its grain running perpendicular to the one before it. Like other glued-wood products, plywood provides a strong, inexpensive alternative to solid wood. It is widely used both in cabinetmaking (for chests, dressers, wardrobes, and tables) and in house construction (for walls, ceilings, subfloors, doors, and in forms for casting concrete).
As with hardwood and softwood sizes, plywood sizing can be somewhat confusing. Plywood sheets usually sold as four-feet wide, but are occasionally found in two and five-foot widths. Similarly, a plywood sheet’s length is commonly eight-feet, but some suppliers carry four and twelve-foot lengths. Metric sizes are also available.
While the length and width of a sheet is pretty straight forward, the thickness dimensions are anything but. The most common sizes of plywood sold in the United States are 3/4″, 1/2″ and 1/4″. However, that’s not exactly correct. A 3/4″ sheet of plywood is really 23/32″ (and is now typically labeled as such). Similarly, 1/2″ should be correctly labeled as 15/32″ and 1/4″ labeled as 7/32″. However, everyone still refers to them as 3/4″, 1/2″ and 1/4″.
Although it doesn’t seem like much, this 1/32″ differential between the actual size and the common size can become an issue when working with plywood. For instance, if a woodworker is building a bookshelf where a 3/4″ plywood shelf is placed into a dado cut into the shelf standards, there will be a very noticeable 1/32″ gap, and the shelf will feel a bit sloppy in the dado. To combat this, the dado should be cut at 23/32″ to ensure a proper fit.
There are about 560 plywood and veneer mills in the USA that produce 20-25 billion square feet of plywood each year. This about 900 square miles of 1-inch thick plywood! About 90-95% of that is softwood plywood.
