Construction techniques

In its simplest form, woodworking involves taking a large piece of wood, cutting and shaping it into smaller pieces and reassembling them in a different order to make something useful or decorative. The cutting and shaping is relatively straightforward bit. It’s when you come to join all the pieces back together again that the fun begins

Joining options Making a beautifully cut joint is one option: using nails is another. The accomplished cabinetmaker with years of experience, will produce exquisite joints executed with the precision of a watchmaker. The site ‘chippy,’ armed with a bucket load of 4in nails and a claw hammer, will assemble a timber stud wall before breakfast.

Between these too extremes there’s a broad middle ground covered by fi xing systems. This series of articles will look at the fi xings and at the specialist tools and jigs available to the home woodworker.

How about dowels? Stop, don’t turn over! Yes, I know what you’re thinking. I hate using dowels… or I did. Trying to get two or three dowels and holes to align perfectly is hard work; more than that, just forget it. There have been (and still are) plenty of dowel jigs available. Some are better than others, but on the whole they’re not accurate enough, too complicated or just not as versatile as I would like.

For me, using dowels the traditional way – marking the position of the holes and drilling them out – has always proved the most satisfactory. The problem is it’s very time consuming, and there are other joining systems that make this method redundant.

A eureka moment All this changed a few years ago when I was demonstrating at a woodworking show. A colleague asked me if I’d seen this newfangled gadget called a Joint-Genie, and pointed me in the direction of their stand. I was immediately impressed!

They say that the best ideas are the simplest, and this thing is simple. It’s quick and easy to set up, and quick and easy to use. It’s compact, not complicated, and I never thought I would say this about anything that claims to position dowel holes, but it really works!

Joint-Genie is a system that can be purchased in various sets. The most popular set for the woodworker is the 8mm Craftsman, and this is the set I’ll be using here. Each set contains a selection of standard components, all available as separate parts so you can develop the system to suit your needs.

How it works The Joint-Genie works by mirror-imaging its position from one component of the joint, photo 1, to the other, photo 2. The main bar is precision-made hardened steel, and has two identical working faces which incorporate dowel drilling guide holes and countersunk fixing holes.

An end-to-end joint The simplest form of joint is the end-to-end butt joint. Although you won’t often need to make such a joint, it will demonstrate how accurate this system is.

Drilling into end grain is hard work on the drill bit. There is also a tendency for the drill to follow the grain, effectively misaligning the hole. Joint-Genie’s precision-engineered 20mm deep guide bar has been designed to hold the drill bit perpendicular throughout the cut. This feature alone will ensure perfect alignment every time. A cordless drill will cope with the challenge, but a mains drill will give cleaner holes because of its much higher drilling speed.

The first drilling Set the drill stop to the required depth, photo 3. In this case the dowels are 40mm long and the bar is 20mm thick. The hole needs to be just over half the length of the dowel (20.5mm), so the stop must be set at 40.25mm.

Clamp the bar to the end of a board. It’s better to hold the board in the bench vice, although you can make the joint holding the board by hand. The bar will ensure that the hole is drilled perpendicular to the end. Bore the dowel holes with the drill set to a fast speed setting, photo 4.

Resetting the jig After you’ve bored the fi rst set of holes, remove the Joint-Genie and reset all the tabs by rotating them through 180°. This reconfi gures the jig to become a mirror image of its original set-up. Clamp the reconfi gured jig to the second piece of the joint and drill the corresponding holes using the same drill/drill stop set-up, photo 5.

After knocking any debris out of the holes, insert the dowels into one component, photo 6, and assemble the joint, photo 7. You’ll see that the end result is a perfectly aligned joint, photo 8. You can make other butt joints such as tee, corner and mitre joints in a similar manner.

End-to-face joints Making a joint where the end of one board is joined to the face of another requires a little more thought, as the dowel hole being bored in the face of a board needs to be stopped before it breaks through the surface. It is this depth that governs the effective length of the dowel.

Where two pieces of sheet material are being joined to form the corner of a carcass, for example, if the material is 18mm thick the hole can be a shade over 15mm deep. The same size hole can be bored into the end of the other component, photo 9.

Although it’s possible to bore a deeper hole in this piece, there’s no practical reason for doing so as it won’t increase the strength of the joint. Also it is far too easy to drill the face board with the drill stop set to the wrong depth. It is always better to reduce the length of the dowel.

Making the joints Making end-to-face joints is similar to making the end-to-end joints discussed above. The main difference is the method of holding the Joint-Genie bar in place when drilling into the face. In this situation, the bar is screwed into place through the countersunk holes provided, photo 10. As the screws fi xing the bar in position will be covered by the other component of the joint, the holes will not be seen.

When making a corner joint, you can use the tabs to align the bar along the end of the face board. However, if the joint is positioned at some point other than the ends, use a guide line to position the bar. The end tab is still used to ensure that the edges of the boards are flush.

Indexing the holes It’s the alignment of multiple holes that has always been a problem when using dowels. Getting three or four holes to align in the same axis is hard enough, but aligning rows of closely-spaced holes is almost impossible without some serious machinery that’s way out of reach for the average woodworker. Not any more: the Joint-Genie can index both horizontally and vertically with pin-point precision, thanks to its accuracy of manufacture.

How indexing works You carry out horizontal indexing by rotating the end tab out of the way after the first drilling. You then move the bar along the joint and insert a dowel into one of the holes, photo 11. After slipping the Joint-Genie over the dowel and securing the bar in place, you can drill the rest of the holes. You can repeat this process over and over again without any loss of accuracy.

For vertical indexing you need to bolt two bars together, photo 12, and bore two rows of holes. You then remove the Joint-Genie and place dowels in the second row (see photo 12 again), so the bars can be repositioned and a third row of holes can be bored. You can once again repeat this simple process as many times as required to create the joint you want.

Making joints with dowels is made so much easier with a good jig system. It’s the simplicity of the Joint-Genie that is its best feature. There are no small pieces to lose, and it’s quick and very easy to use. Over the years I’ve tried and dismissed the use of dowels – but not any more. I’ve now used up all the dowels lying around my workshop, and have had to go out and buy more!