Make tight strong and attractive joints the oldfashioned way without a drop of glue

there are some guidelines you can follow to get a strong joint. The size of the tenon, key, and key hole all play an important role. I like to make the keys first. But you need to size them for strength and looks.

sizing the key. When you think about it, there's a lot of pressure on a keyed mortise and tenon joint. Especially as the key is tapped into place. The goal is to make the key strong enough without looking too bulky. You want it to be proportional to your project's size.

For strength, I like to make the thickness of the key about one-third the width of the tenon. The drawing at left shows what I mean. And I think it looks better to have the small end of the key square-shaped, as shown at left.

tapering the key. There's another important factor in the design of the key — and that's the taper. If you put too much of a taper on the key, it'll have a tendency to fall out of the tenon. But if it doesn't taper enough, you won't be able to tighten the joint if it works loose. If you use a taper of about 1:6 (or 9°), it'll work out just about right.

Sometimes called "tusk" tenons, keyed mortise and tenons are the original knock-down joinery for furniture projects. A wedge-shaped "key" holds a tenon in place for sturdy construction (see photo above). What's nice is, as the seasons change, you can tighten up a loose joint with a small tap on the wedge. With another small tap, you can remove the key so that you can take the joint apart.

It's not difficult to make a keyed mortise and tenon joint. But there are a few tilings you should know to get great results.

careful uyout. if you look at the drawing below, you'll see that

Make tenon long enough to withstand pressure from the key

•~Thickness of key is about V} width of tenon

Hole for key is set back from face of mortise

Hole for key is set back from face of mortise

This length determines the strength of the joint

Now, you can move onto laying out the tenon for size. It's got to be strong enough to take the pressure the key places against it.

TENON LENGTH. One important dimension for the tenon is its length. If it's too short, you can split out the short grain on the tenon as you tap the wedge in place. But if it's too long, it can look out of proportion with the size of your project.

There's no hard and fast rule, but for strength, it works better to make the tenon longer. There needs to be enough "meat" on the end of the tenon to prevent splitting out (see drawing, opposite page).

The last piece of the puzzle is laying out the hole for the key.

sizing the hole, You want the key to pull the shoulders of the tenon tight against the back face of the mortised piece. To do this, you need to make sure the back of the key contacts the mortised work-piece instead of the back side of the hole for the key. That's why 1 like to offset the hole inside the mortise, as in Figures 1 and 2,

Next, I'll lay out the width and length of the hole and drill out the waste with a brad point bit. I try to drill to the "back" side, or "shoulder" side of the hole as shown in Figure 3 on the right.

The next thing to do is to pare three sides of the hole square (Figure 4). Finally, the side of the hole at the end of the tenon needs to be

/ Make a line offset toward the >>_ fen on shoulder

Original mark

Mark the tenon - cheek at the mortise

Lay out hole for key ,

NOTE: Use ^ backing board

NOTE: Use backing board

I ; Remote waste

II 1 in thin slices, checking 1 ■ t/ie fit of the key

SIDE SECTION VIEW

Pare the —y ™ bevel side at a taper to match the key <9°)

Backing board in the hole. If it's too tight, you can sand a little off the straight, or back, edge until you get a good fit. I like to fit the key so that it's centered on the tenon yet still draws the joint tight. Then all it takes is a gentle tap to lock the joint in place. ESS

angled to match the taper of the key {Figure 5). 1 start with light paring cuts and check the taper often, using one of the keys as a gauge.

put it together. Now that you've got all the pieces, you can assemble the joint and test the fit of the key

Leave waste to sand for - final fitting

Tilt saw blade 9'

Leave layout fine

Sandpaper on flat surface

Fitting. To adjust for a tight-fitting key, sand the back side until you get a good fit.

Shaping. Final shaping is done using the band saw and sanding smooth.

Wood smith

The Taper. Tilt the blade on your table saw to 9° to cut the tapered keys. By flipping the workpiece, you can cut several of them.

www.Woodsmith .com

a Loft Bed. This space-saving bed has a built-in desktop with handy organizers. And the rugged, bolt-together construction will stand up to years of use. Best of all, you'll find that building it won't take lots of time. Check out the step-by-step instructions starting on page 24.

A Dressing Minor. There's a lotto like about this stylish mirror frame. For example, you'll learn how to dress up a basic mortise-and-tenon frame with decorative overlays. Tak a look at the easy-to-follow instructions on page 34. ^Jk looking inside

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