Projects with dovetails imply a level of craftsmanship and detail that adds both inherent strength and pizzazz. You can cut them by hand, but for reliability and quick repeatability, you just can’t beat a good router-assisted jig. If you’re going to invest in a jig, it makes sense to get one capable of creating all of the most common joints: through- and half-blind dovetails as well as box joints. We put seven such jigs through rigorous testing, and found good options in several price ranges.
Start with a cost analysis
The jigs we tested range from $130 to $600, but only four include everything you need to create through- and half-blind dovetails and box joints right out of the box. For example, the three sub-$200 jigs require purchasing at least one additional router bit to make the three joints. In fact, the CMT 300 ($130) does not include any bits, so you’ll need to buy $185 of accessories to create all three joints. The Porter-Cable 4216 and Rockler 22818 jigs come with everything except a straight bit for making box joints.
The essentials of operation
Each tested jig requires a guide bushing mounted in the router’s subbase—or, in the case of the Leigh RTJ400, the router table—to steer the bit around the fingers on the templates (see photos below). CMT’s guide bushing must be attached with screws, so it won’t fit many routers. But, we successfully substituted a common two-piece guide bushing, shortened to work with the thin CMT template.
Workpiece stops locate boards precisely in the jig for the joint you want. Built-in clamps hold workpieces securely, and a backer board you provide prevents tear-out where the bit exits the wood. Once set up, you can duplicate the joint indefinitely with identical results.
Because each jig is designed to work with specific geometries of dovetail joints, it’s best to use bits recommended by the jig’s manufacturer. Other brands with identical geometry should work, but you risk slightly imperfect joints. We got the best results using bits with 1⁄2 " or 8mm shanks; 1⁄4 "-shank bits tended to vibrate and chatter more. (The jigs that use 8mm-shank bits include a reducer that fits into a 1⁄2 " collet.) Some jigs, such as the Porter-Cable (shown above), have onboard tips and gauges for quick setup of the bit and template. The Leigh RTJ400’s quick-reference strips, that slide into the top bar, help guide you in cutting each joint.
A quick joint primer
Jigs determine workpiece size
All the tested jigs accommodate workpieces at least 11" wide. The Leigh D4R Pro handles boards up to 24" wide, and the RTJ400 up to 16" wide. (See the chart for capacities for the different joints.)
Spacing of the template fingers plays a key role in determining the width of your workpieces. Dovetail joints look best with symmetrical pins and tails and a half-pin on each end. Most of the jig templates have fixed fingers, so you must size your workpieces to the template, as shown below. The jigs that use fixed-finger templates range from 13⁄16 " to 1" spacing for half-blinds, and from 13⁄16 " to 13⁄8 " for through-dovetails.
For the smoothest cuts, especially on tear-out-prone end grain, choose a router bit with shear (angled) cutting edges or downcut spiral edges.
For more versatility, the Leigh D4R’s movable half-finger guides, shown above, can be positioned wherever you like, letting you adjust the size and spacing of both tails and pins, and the workpiece size. Similarly on the Leigh Super 12, shown below, you can vary the width of the tails, but not the pins, on any width workpiece that fits in the jig.
The best jigs in the joint
Our Top Value honor goes to the Porter-Cable 4216. It sells for $180 without bits for box joints, but if you only want to make dovetails, it’s a great bargain—and performer—at that price. And if you already own straight or spiral bits, box joints won’t cost you extra.
The bottom line on the jigs and their joints
Leigh D4R Pro, $600
Not only can you work on 24"-wide stock (think blanket chest or toy box), but you also get infinite variable spacing of pins and tails, and the ability to create additional decorative joints, such as keys, clovers, ellipses, waves, and bear ears, with optional bits. It has the same quality, owner’s manual, and support as the other Leigh jigs.
Bottom line: This top-of-the-line jig offers the most versatility and capacity, with a price to match.
Porter-Cable 4216, $200
(including optional box-joint bit)
You get templates for making typical half-blinds, through-dovetails, and box joints, as well as templates for making smaller versions of those same joints.
Bottom line: We found this jig easy to use, accurate, and easy on the wallet.
MT 300, $315
(including necessary optional accessories)
After you purchase the necessary router bits, templates, and guide-bushing subbase, this jig helps you make perfect-fitting joints. But the critical tiny screws and parts can be easily lost.
Bottom line: If you just want to get a jig to make half-blind dovetails, this model (plus the optional $20 bit) provides a great value at $150. You can grow the system to through-dovetails and box joints as you go.
Leigh Super 12, $275
This jig oozes quality and versatility, and with it you can make four types of joints right out of the box. Leigh’s owner’s manual superbly walks you through each step, and its online videos provide valuable backup if needed. (This jig also sells in 18" and 24" versions.)
Bottom line: It’s the lowest-priced jig with variable spacing, and well worth the investment.
Leigh RTJ400, $330
Although it lacks the variable spacing of the other Leigh jigs, it’s easy to use and creates perfect joints. We like the better visibility that comes from using a router table. And it has an equally thorough owner’s manual and online support.
Bottom line: Get this jig if you prefer working on a router table versus using a handheld router.
MLCS 8701, $200
With patience and trial-and-error, you can make acceptable joints with this jig. But the vague owner’s manual with unclear photos left us guessing on many steps. MLCS also sells a version of this jig (no. 8711) for making only half-blind dovetails ($60).
Bottom line: It’s hard to make a case for buying this jig.
Rockler 22818, $200
(including optional box-joint bit)
Out of the box, we were able to make half-blind and through-dovetails after a slight learning curve. Making box joints requires an optional bearing-guided pattern bit—no guide bushing—but we can find easier ways to make box joints. Buy optional templates ($40 each) to make through-dovetails of wider spacing, and an optional template-and-bits kit ($70) lets you make miniature through-dovetails.
Bottom line: This is a reasonably priced, good jig for making half-blind and through-dovetail joints in stock up to 11" wide.