Tool review: Tablesaw Tenoning Jigs

At first glance, a tablesaw tenoning jig looks intimidating with all those knobs and movable parts. Fact is, you'll use only a few of those parts for 99 percent of your work, and these simple accessories prove so easy to use, you'll wonder why you didn't get one sooner.

Popular sentiment among woodworkers suggests that all tenoning jigs are the same, so you should just buy the least expensive one you can find. We beg to differ. Half of the jigs in our test were pretty much interchangeable, but one stood clearly above the rest. And by the time you reach the end of this article, you'll know exactly which one to buy.

Using a dado set to cut tenons on a workpiece laid horizontally on the saw invariably leaves ridges and shallow grooves on the tenon cheeks that weaken the joint (unless you tediously sand or hand-plane them smooth). But a tablesaw tenoning jig secures the workpiece on its end to cut the cheeks with an ordinary saw blade [top photo], leaving them jointer-smooth.

Looking at the Tenoning Jig Anatomy photo, you'll see that each jig has two main functional areas: the work-holding area (components labeled in gray), and a workpiece-positioning area (parts marked in black) that controls the size of the tenon.

To use the jig, clamp the workpiece with one face against the support plate and one edge against the fence. Set the blade height to cut the length of the tenon. Next, loosen both the sliding-base lock and the microadjust lock, and move the sliding base to correctly position one face-cheek cut. Engage the microadjust lock to dial in the cut precisely. Now, secure the sliding-base lock and make the cut by pushing the jig and workpiece through the blade. Repeat the process for the opposite face cheek and the two edge cheeks. Make the shoulder cuts to remove the waste (using a miter gauge) either before or after you cut the cheeks.

The simple and repetitive process typically requires repositioning both the clamp and the sliding base when you switch from cutting face cheeks to cutting edge cheeks (unless your workpiece and tenons are square). So, let's start by rating the adjustments you'll make most frequently.

Ideally, you want to center the threaded clamp rod--and the force--on the workpiece, so that means adjusting the arm fore and aft, and locking it in place. We like locks that require no tools to secure. Some models need a hexhead wrench (one more thing to keep track of) to operate the arm lock.

As for adjusting the clamp itself in and out to accommodate different workpiece widths, look for a clamp with a quick-release [photo] to speed adjustment. Instead, you might also consider one of the models with a speedy steel crank, because they keep one hand free for holding the workpiece.

All but two of the tested tenoning jigs use sleeve-type microadjust systems for moving the sliding base left and right to adjust the tenon size: The microadjuster threads into a sleeve that moves freely in the sliding base when the microadjust lock is loosened. That's your coarse adjustment. Securing the lock fixes the sleeve in the sliding base so that turning the microadjuster moves the base in a slow but controlled fashion. Overall, this style of lateral adjustment works fine, but requires locking and unlocking two closely spaced ratcheting lock levers (the sliding-base lock and microadjust lock).

So we prefer the models with more intuitive adjustments [photo]: You push and hold the quick release, slide the base, let go of the quick release, and dial in the precise alignment. One knob locks it down.

• You may only have to make the critical jigto-blade alignment when you first set up your jig, but we gave high marks to those that could be adjusted without taking apart the jig. (Most require removing the sliding base from the baseplate, or, at worst, the entire jig from the tablesaw.)
• When pushing a workpiece through the blade, one vertical handle at both the front and rear of the jig gave us better control than one vertical and one horizontal handle.
• The miter bars on most of the tested jigs have builtin adjustments to fit the bar to your saw's miter slot. On those without, you'll need to peen or file the bar to fit.

Delta's 34-184 stood tall above the rest of the jigs in this test with great features and precise performance, earning our Top Tool award. Jet's JTG-10Q also scored well, sporting the best of the sleeve-type microadjusters, a rock-solid clamp, and a price tag the same as the Delta. In the under-$100 price tier, the jigs are so similar in function and performance that we'd go with the bottom-dollar Grizzly, making it our Top Value.