The router has, in recent years, become something of a must in the cabinetmaker's and even the finish carpenter's workshop. Its presence isn't due to the fact it does new things, performing tasks that other tools cannot.
In truth, a dado and a molding head mounted on a table or radial-arm saw will perform many of the same tasks, like cutting grooves and shaping molded edges. The router will cut mortises(more easily, faster, and, with the appropriate templates, more accurately than hand chisels) and dovetails (again, with an appropriate guide). And it will trim plastic-laminate edges for countertops, which almost nothing else will.
It is the router's versatility-the fact that it does all these jobs-as well as its light weight, reasonable cost, and portability, that have made it the tool of choice for many of them.
The router shares its name with a hand plane that predates it by a few centuries. While today's power router accomplishes some of the tasks its ancestor used to (cutting grooves and rabbets), its lineage is closer to that of the electric drill.
Mounted on a round base, the motor of the router drives hits that protrude from the center of the base. It is most often operated with its base held horizontally, and flush to a workpiece. Its bits are mounted in a collet chuck, and the tool is held firmly with two hands grasping the pair of handles that flank the motor housing. The motor is preset to a position with respect to the base; where it is set determines the depth of cut.
As with most power tools, not all routers were created equal. There are inexpensive models and there are quite costly industrial-grade routers. Some weigh as little as three or four pounds, some more than twice that.
Speed is an important criterion in selecting a router. In the simplest possible terms, the better the router the faster it spins its bit. Maximum speeds range from fifteen to twenty-five thousand revolutions per minute or more. The advantage of greater speed is cleaner cuts: The high speed produces smoother surfaces, requiring a minimum of sanding. Some routers have electronic speed controls that adjust the speed as the router works, selecting the speed appropriate for the material and the size of router bit being used.
Power is another consideration. Some routers have as little as a one-half horsepower, some three horsepower or more. For most home craftsmen, however, one and a half horses are probably quite adequate. The less powerful machines may require more than one pass to produce a cleanly shaped groove or molding.
The ease with which bits can be changed and the depth set is another consideration in selecting a router. Chuck sizes vary, too: the collet chuck on the smallest models can accommodate bits with quarter-inch shanks, larger models half-inch diameter shanks. A more varied range of bits is available for routers with half-inch chucks.
Accessories. Guide fences are sold for use with most routers. Attached to the base of the router by guide rods, the adjustable fence enables you to make cuts parallel to an edge, to cut mortises and tenons, and even to cut grooves in the edge of a workpiece. Some have a Vernier scale and set screw set into the guide for precise adjustment; others can be used as a trammel to cut circles by fixing one point around which the router is turned.
Routers can also be affixed to the underside of a specially designed table. In this arrangement, the router is inverted, its cutters protruding through the tabletop. This transforms the router into a small-scale (and quite affordable) shaper. Workpieces are presented to the bit face down, with the edge pushed past the router bit. Quality router tables have blade guards, an adjustable fence, and miter gauge (with matching slot) that allows for end-grain and miter work.
Another accessory allows the router to be used as a biscuit joiner. A wide range of templates are sold, too, some of which make routing butt hinges a breeze; others are for dovetails or lettering or numbering. There are more options than there is space to describe; one adapter even allows the router to be used like a lathe. But you would do well to begin by using the tool for simple cuts, to get a feel for it and learn its idiosyncrasies. Then expand your repertoire as you desire.
Plunge Routers. Plunge routers are designed for making interior cuts: trying to drop a regular router into the middle of a piece of stock with its bit racing isn't at all a good idea. The plunge router brings precision and safety to the process.
The housing of the plunge router is mounted on a base with two posts that telescope, allowing the bit to be “plunged” into the work- piece from above. A depth stop is preset; then a locking lever is released, allowing the sliding carriage to be driven into the workpiece. When the operator releases the downward pressure on the router, springs return the carriage to the top of the stroke.
Plunge routers are especially useful for making stopped grooves or dadoes (in which the cut terminates before the end of the workpiece), mortises, and template-guide cutouts.