Fine furniture- and cabinet-making projects often involve building joints without screws or nails, thereby keeping focus on the wood's natural beauty instead the fasteners. While nails and screws have their place, especially in primitive pieces, their presence is obtrusive in anything even semi-formal. Butt or mitered joints held only by glue don't stand up to the stress of continued use, so furniture makers long ago developed joinery using hidden strengtheners. Now I don't know about you, but I have neither the expertise nor the tools to create blind tenons. Most woodworkers with even a modicum of skill, however, can pin a joint with dowels. That entails "only" properly marking and drilling the hidden surfaces of the joints, inserting dowels with a little glue, and clamping the joint as it dries. Marking and drilling, happily, is made easier with doweling jigs - of which I have not one but two.
I already reviewed my Wolfcraft Dowel Quick Doweling Jig (4641), a mostly-plastic affair that can be used to drill holes for dowels on both boards in a joint. With a little patience (and some careful study of the rather cryptic instructions) you can build a sturdy joint that will withstand years of use. That's not my only doweling jig, however, I also own a more professional jig; the Dowl-It 1000 - sometimes rendered as the "Dowel-It 1000" though the manufacturer has left out that E for sixty years now. In fact, I first used a jig like this in junior-high shop class in the early sixties - and the design remains unchanged.
The Dowl-It 1000 has a solid-feeling, all-metal construction (no plastics in this All-American product), with no loose parts to lose; unlike the Wolcraft jig on both counts. The Dowl-It is essentially a hand-sized version of a woodworker's vise made of machined aluminum, with a steel alloy hole guide (a block pierced by six different-sized holes) in the center. The clamp capacity of the 1000 ranges from slightly less than ½" to two inches. When the jig is tightened on a work piece, the hole guide is aligned with the center of the exposed edge. The clamp works on either round or square stock. The hole guide allows precision placement of a hole for six common dowel sizes (3/16, ¼, 5/16, 3/8, 7/16, and ½ inch); the guide holes are chamfered to allow easy insertion of a twist-drill bit - the jig is not to be used with spade bits. A window in one side reveals lines centered on each hole, scored into the side of the guide block.
Using the Dowl-It requires more care than the Wolcraft, however it also tends to produce superior results. Doing so requires that the woodworker clamp the two sides of the joint together and mark them simultaneously. Then clamp the workpiece in the jig with the proper index aligned with the mark and drill through the guide. Then move the jig to the other index hole(s) and repeat the process. The resulting holes are straight and centered, regardless of the thickness of the board. Repeat on the other side of the joint; insert dowel pins (Wolcraft fluted dowel pins work quite nicely) with glue, assemble the joint, and clamp.
From my use, I've found that the woodworker's axiom "measure twice, cut once" holds just as true for aligning dowel pins as anything else. This is a quality hand woodworking tool that requires careful use. Sloppy measurement and slap-happy usage will yield poor results; care and caution will reward the user with precision results.
The Dowl-It company of Hastings, MI, makes eight different models with clamp capacities up to six inches; some with larger hole sizes; some with replaceable bushings for the drill guide. They're expensive but precise - and worth it.