The router is by far the most adaptable joint-making tool in the workshop. Numbers of commercial jigs and router bits have been developed over the years that enable the tool to produce many common joints, such as dovetails, box joints, and mortise-and-tenons, and perform other, not so common, operations. The jig shown in the photo at right, for example, relies on router-like cutting action to cut pocket holes. Although the jig can accomplish little else, it does the job of assembling face frames quickly and precisely. Other commercial router jigs are illustrated starting on page 88. Some of these devices are expensive, and if you plan only to make the occasional joint, you may be better off doing the work with hand tools. But if your upcoming projects include a lot of repetitive work—a chest of drawers with plenty of dovetailed joints or a series of doors with mortise and tenons, for example—these jigs can quickly prove to be a worthwhile investment.
Although the router is seldom used freehand to cut joints, very few router joinery techniques absolutely require an expensive commercial jig. The only accessory needed to rout sever
al common joints is a router table. With a three-wing slotting cutter and an auxiliary fence on your table, for example, you can produce double dado joints (page 90) for assembling drawers. Another interlocking joint that is simple to cut on the router table is the lock miter joint (page 96). A table will also enable you to convert your router into a plate joiner; the simple setup shown on page 94 simplifies cutting slots for the biscuits, which swell when glue is applied, creating a sturdy, invisible joint. And although through dovetails are traditionally crafted by hand or routed with the aid of a commercial jig, the technique beginning on page 104 shows how to create this strong, attractive joint on the router table aided only by a miter gauge.
You can enhance your router’s joint-cutting capacity with a variety of shop-built jigs. The simple T-shaped jig shown on page 92, for example, is ideal for routing half-lap joints. The biscuit-slot jig (page 95) transforms a hand-held router into a plate joiner. And the jig shown on page 97—essentially a work surface with a slot cut through it—will serve as well as a commercial device for routing mortises.
There are scores of commercial router jigs available today.
Some, like the Keller jig (page 89), are as simple as a set of metal templates that guide the router as it cuts a joint. Others, like the WoodRat shown below, are elaborate, adjustable devices that can be set up to cut several joints. The four jigs shown on this and the following page represent a cross section of what is available in terms of versatility and price. The advantage of a jig is that it permits you to produce a lot of joints precisely and quickly. And, it often eliminates
the need for hand-work skills. It is much harder, for example, to cut a good-fitting dovetail with a hand saw and chisel than it is to use a router and a jig. But there is a tradeoff: Many seasoned woodworkers complain that nothing can match the look of a handcrafted joint. The regular spacing of the dovetails of a fixed template is too predictable and looks too machine-made, they say. The Leigh jig solves that problem by offering a way to adjust the spacing and width of the pins and tails. But of course, that extra flexibility comes
This is a sophisticated jig capable of cutting a wide range of joints, including through and half-blind dovetails, lap joints, morti$e-and-tenons, tongue-and – grooves, and rabbets. The router is held upright on a metal plate on the jig and one or more workpieces are clamped on a sliding bar below the plate. The router can be guided along the plate into a stationary workpiece, or the stock can be fed into the bit by turning a handwheel, as shown in the photo at left. The setup time is considerable but the jig offers some appealing advantages. Since the stock can be fed with the direction of cutter rotation (normally, an unsafe practice) the resulting cuts are extremely smooth with virtually no tearout. Also, work held in the left-hand clamp automatically adjusts work held in the right-hand clamp, so if you adjust the setting to cut the tails for a dovetail, for example, the pin adjustment is simultaneously indexed. The jig is also ideal for production-type operation; the dovetails for up to a dozen work – pieces can be cut at the same time in a matter of a few minutes.
The Incra is installed on a router table to replace the standard fence. It is simply screwed to a piece of plywood and then clamped to the table. The jig features fine adjustments that allow the fence to be shifted in precise increments —with an accessory, as fine as 0.001 inch. ‘The Incra can be used to cut either dovetails or box joints, as shown at left.
with a higher price tag and usually involves more setup time than a fixed-template type of jig.
Most commercial jigs are designed to cut dovetails, since this joint is a cornerstone of cabinetmaking and one that seems tailor-made for the router to produce. There are also jigs for cutting mortise-and-tenons, like the MorTen shown on page 101, while some dovetail jigs, like the Leigh, can be adapted to cut both dovetails and mortise-and-tenons. Before buying a jig consider whether you need all the features that
Leigh Dovetail Jig
The Leigh’s distinctive feature is its finger assembly, which, as shown above, can be adjusted with a screwdriver to alter the spacing and width of the pins, giving a handcrafted look to the dovetails it helps cut. Once the pins are adjusted, the tails are set automatically. The finger assembly is simply flipped over to cut the mating part. The finger-guide assembly can be adjusted precisely to fine-tune the tightness of the joint. The jig can be used to cut a variety of dovetails, including through, half-blind, sliding, and outlined. An attachment also enables it to rout mortise-and-tenon joints. The jig is available in 12-inch and 24-inch models.
it provides. There is no point buying a device that requires an hour or two setup time if you only plan to cut a few joints. On the other hand, one big project may make the purchase of a jig pay for itself. A traditional six-board blanket chest, for example, requires more than 50 dovetails. Unless you are very experienced, those joints will take you hours— if not days—to cut by hand. A simple jig like the Keller, on the other hand, would enable you to do the job easily in a single morning.
The Keller is a simple, fixed-template dovetail jig, of which there are numerous varieties on the market. This particular device consists of two templates—one for cutting the pins and one for cutting the tails. The templates are mounted to backup boards and then clamped to the workpiece. A dovetail bit is used to cut the tails, as shown in the photo below, while a straight bit routs the pins. Each bit has a bearing that guides the router in and out of the jig’s fingers to cut the joint. A stop-block (clamped to the right of the workpiece in the photo) makes it easy to cut any number of joints with the same setup. The jig is available in 12-inch and 24-inch models.