Profiles made in wood by several common router bits.

A router (pronounced rhowter) is a woodworking power tool used to rout—that is, to cut grooves, hollow out areas, or create shaped trims along the edge of a piece of wood. The depth and shape of cut that is created is determined by the size and shape of the bit held in the shank.

The tool usually consists of a vertically mounted motor that drives the shank, with the bit, held in a collet, projecting out through a flat base. Control is derived from two handles on either side of the device. There are two standard types of router - plunge and fixed. With a plunge router, the bit can be lowered into the wood while keeping the base flat; with a fixed router, the cut depth may not be varied while the router is operating.

There is often a circular baseplate affixed to the bottom of the router that can slide along an edge to guide the router's path. This is important because the direction of the router bit's cutting edge against the wood (relative to the direction of the router's progress through the wood) tends to pull the router slightly offcourse, so that cutting perfectly straight channels without a guide (i.e., freehand operation) is a painstaking process and rarely as effective as using a guide.

As an alternative, the tool can be mounted below a router table (as with a circular saw) and used in conjunction with a fence. In most router tables, the shank of the bit is fixed in a vertical position. Some tables allow the router to be mounted in alternate positions, in which the shank of the bit is held horizontally or in another orientation.

The router is a versatile tool. As described by Hylton and Matlack (see Books below), "you can use it in just about every aspect of a job but assembly ... used creatively, it'll do almost any kind of cutting or shaping of wood." However, custom baseplates, templates, or jigs - tools that help guide the router or the workpiece through a controlled motion - are typically needed for more complex cuts.

A tool similar to a router, but designed to hold smaller cutting bits - thereby making it easier to handle for small jobs - is a laminate trimmer. Another related tool, called a shaper or wood shaper, can be used for deeper or larger-diameter cuts.

Router bits come in hundreds of varieties to create both decorative effects as well as joinery aids. They are classified as either high-speed steel (HSS) or carbide-tipped, and can be edge bits or non-edge bits. Edge bits have a small wheel bearing to aid a router along the edge of a piece of wood without using a rip fence. Non-edge bits are guided with a straight edge, rip fence, or a router table. Bits also differ by the width of their shank, with half-inch and quarter-inch shanks being the most common. Half-inch bits cost more than quarter-inch bits, but are stabler (for smoother cuts) and safer from shaft breakage. A bit can only be used with a collet that is appropriately sized for its shank. Many routers come with collets for both the popular sizes.

Most routers allow the speed of the bit's rotation to be varied. A slower rotation allows bits of larger diameters to be used safely. Typical speeds range from 10,000 to 24,000 rpm.

Books