Tips and techniques for beautiful bowties
Furniture made from thick wood slabs, with gorgeous grain and natural edges, at once rustic and refined, has remained popular ever since George Nakashima first introduced it to U.S. woodworkers in the 1950s. Better yet, woodworkers of almost all skill levels can build something with a natural-edged slab.
If you can get your hands on a beautiful slab and find a way to smooth its faces—buying time on an industrial sander or using one of many homeshop methods—you can find a way to showcase your unique find.
While I prefer the thick furniture bases Nakashima favored, which root these tree sections to the earth, others place slabs on welded steel bases, reclaimed industrial equipment, or stylish hairpin legs that simply bolt on.
Enter the Butterfly Key
The main calling card of these beautiful log sections is their close connection to the tree, and natural defects are embraced. Large splits, however, can make big slabs unstable. Nakashima had the perfect answer here too—butterfly-shaped inlays that bridge gaps and splits—a soulful, handmade touch that is both decorative and structural.
Because the inlay is shaped and traced onto the wood, which is then excavated to house it, butterfly keys can be almost any shape or size, and vary from key to key. That means you can, and should, design them to suit the job at hand—as Nakashima did—long and thin for wide gaps, short and fat for long cracks, and so on. Vary the angles and elements beyond the classic profile, and you can make an already unique slab completely yours.
While the inlay process is simple in concept, it can be tricky in practice. And the stakes are high: Mess it up, and you get obvious gaps.
Side Taper is the Secret
Stealing a page from the master, I add a slight bevel to the sides of my keys—roughly 1 degree or so, depending on the hardness of the woods—which makes the inlay process more forgiving. Stray a little with your knife or chisel, and the key fills the gaps as you drive it into place. The wood in the slab compresses a little to accommodate the slightly over-sized key.
The question is how to add that bevel in a consistent way. If you bandsaw your keys, as most do, you can impart the slight bevel as you smooth the edges on a hard sanding block. That works OK, but I’ve worked out a more consistent approach.
If you’ve got a benchtop sander something like mine—an oscillating edge/belt spindle sander, one of the best values in woodworking, in my humble opinion—you can create a new twist on the butterfly key and get perfectly beveled edges in the process.
What makes this sander great for this task is the access it allows to the round drums at both ends of the belt, and also its tilting table. By tilting the table a smidge—or shimming a piece of thin MDF or plywood on a table that doesn’t tilt—and using both ends of the belt to smooth the keys, you get perfectly tapered edges and a gently rounded neck, which I find more graceful than the sharp junction on the classic key. As for the rest of the process, I’ve got some helpful advice there as well.
Beautiful Butterflies, Step by Step
For a start, here are some key dimensions and angles that work well. To create the mechanical strength you need, keys should be at least 1/4″ thick, or 3/8″ for big splits in big slabs. Some woodworkers inlay much thicker keys, but I find that to be overkill, and not worth the increased difficulty. If the split goes through the entire slab, I just add a similar key on the back side. As for the dovetail-shaped angles, I find that anything between 8 and 10° looks and works great.
For the side bevels along the edges, 1° is a good target. For very hard woods like maple, or less-forgiving are-as of a slab with knots or wild figure, I ease up on the bevel angles a little, maybe closer to 0.5°. In those cases, I place a flat block over the key as I bang it into place, to help keep it from cracking or splintering upward. In softer slabs like fir or pine, a 2° bevel works well, and hides even more of your subtle mistakes.
As for which woods to use, I like the simple elegance of keys made from the same species as the tabletop, but contrast can be lovely too. If you’re mixing woods, choose a harder wood for the key, so the slab gives way as you drive it in, not the key itself.
I always use a marking knife to trace my keys. It’s a little harder to control than the sharp pencil that some prefer, but the knife hugs the inlay much more closely and leaves a line I can drop my chisel into for the final paring cuts.
Where some simply hold down the inlay while tracing it, I don’t trust my shaky hands to keep it stable, and gaps in my furniture keep me up at night. So I use a few blobs of hot glue to lock down each key for tracing.
The rest of the process is pretty typical for all types of inlay: you rout to establish the depth of the pocket, and chop to the line with chisels. It’s all covered in the photos.
By the way, I don’t like filling defects with epoxy—tinted or otherwise. Wood moves and will eventually pop out some of that hard plastic filler. I strip the bark off the edges too, for the same reason: It’s bound to work itself loose over the years.
Asa Christiana is the former editor of Fine Woodworking magazine, now living and working in Portland, Oregon. His 2017 book Build Stuff with Wood is a guide for true beginners. You can find him on Instagram @buildstuffwithasa
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