Four proven techniques for working with timbers

How to build it big in the great outdoors

By Steve Maxwell

lumber

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Clothesline poles, mailbox supports, bird-feeder stands and garden trellises are all some of the big and beefy outdoor projects I’ve tackled, and all are based on the same four woodworking strategies.

Cutting and fitting big lap joints is the first and most basic technique. You’ll need a circular saw, a 1"-wide chisel and a mallet to make these happen. Start by laying one timber squarely on top of another at the point that they’ll join and then scribe the width of the top timber onto the bottom one using a utility knife. Lumberyard 6x6s and 8x8s vary in size, so you’ll definitely need to custom-cut each lap joint to get a tight fit.

Use your circ saw to cut on the waste side (inside) of each layout line. Then, complete a series of cuts in between these first two, no more than 1/4" apart. Next, clear out the remaining wood with your chisel and mallet.

As with any lap joint, you’ll need to adjust your saw so the depth of cut extends down to precisely the middle of your timber. This adjustment is easy with 6x6s, but standard circ saws can’t cut deeply enough to get to the middle of an 8x8. I complete both of the critical shoulder cuts on the biggest wood with a Japanese handsaw, then use a chainsaw to complete the waste cuts in between. With the waste chiselled out, fit the timbers together, then mark and cut the other piece so the two interlock with both faces flush.

The perfect pegs to hold timber lap joints together are 1/2"-diameter, hot-dipped, galvanized carriage bolts, with flat washers and nuts. Use one bolt for each 6x6 joint and two for 8x8s.

Need to add support to a horizontal timber? You can let in a 45º knee brace by drilling and chiselling side pockets, or use 5/8"-diameter lag bolts to secure butt-joined knee braces to the faces of posts and beams.

Your timbers may fit together with precision, but a perfect lock won’t help with the look. What’s missing is style; and to add to that, you can’t beat chamfered edges and angled ends. A 2/4 "-diameter, 45º chamfer bit in a 21/2-hp or 31/4-hp router is my favourite tool for refining the edges of timbers.

Chamfers look best when they don’t quite extend to the edges of joints and ends. Leaving a little bit of square-edged wood in these places is a classic detail, but it’s not without risk. Depending on the grain of the timber, the router bit may lift the corners in long slivers as it progresses, splintering wood beyond the point at which you want your chamfers to stop. Eliminate the problem by completing a careful plunge cut at each end of the chamfered zone before routing the remaining section of the profile.

Angling the ends of timbers to form a pyramid shape is a three-step process that adds a lot of class. In fact, it’s essential.

Start by tilting the blade of your circ saw to complete four square cuts around the perimeter of the timber near the end, one cut on each face. I’ve settled on a bevel angle of 15º to 20º from square for this work, but the angle is a matter of personal taste. None of these cuts will go deep enough to remove the block of waste wood completely from the end of the timber, since regular circ saws don’t have sufficient depth of cut. You’ll need to complete each pass using a handsaw. No need to cut all the way through from each side; just saw as far as the peak of the pyramid and the whole waste block will come off.

No matter how skilfully you cut the facets on the ends of your timbers, saw marks and inevitable inaccuracies will make the surfaces look less than ideal. Don’t worry. This is where your belt sander can help. Sling a fresh 80-grit belt onto the tool, then gently hold the spinning surface against each facet of the pyramid, one at a time. The sander not only smoothens the surfaces, but it also allows you to fine-tune the angle at which they meet each other. Give timbers a once-over with a random-orbit sander before final assembly for best appearance.

None of these techniques are complicated or difficult to master. But taken together, they take your backyard work to the next level.


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