Randy Johnson's Marvelous Spirals
Making a nautilus, almost like nature does
A nautilus made of maple and purpleheart woods with a 6.5-inch mouth, $650; 5-inch mouth, $425; 7-inch mouth, $650
It isn’t easy to explain how Randy Johnson of Hudson builds a wood nautilus. He didn’t originally start with a pattern out of Woodworking Magazine, but rather stumbled upon the technique by putting together wedge shapes — shapes of wood similar to a doorstop — that were leftovers from other projects.
Johnson has been a woodworking hobbyist for years, a passion that started when he dabbled in his father’s shop as a youngster. Now, in his own well-equipped shop, he has spent about 12 years evolving his nautilus designs. “I used pine at first, because then my mistakes were less expensive,” he says. Yes, it took him a while to figure how the angles of the wedges taken from a straight board affect the final form.
Surprisingly, the process is similar in design to the way nautilus shells grow in nature. Late 17th-century mathematician Jacob Bernoulli called these logarithmic spirals the “marvelous spiral,” and marvelous they are. As the size of the spiral increases, its shape is unaltered with each successive curve, a property know as self-similarity. When Johnson sets his scroll saw angle, he maintains that same angle for each successive piece.
The process takes many cuts and a lot of pieces — about 150 for a medium-size wood nautilus form. Johnson glues the slices together after carefully sanding each side with sandpaper on glass to ensure a perfect fit. On the narrow side, he cuts a half-moon shape in each section, which becomes the inside for the form when sanded smooth. As he adds another wedge, the shell grows its curl. Larger forms can turn 960 degrees — three revolutions. Finally, the form is given a finishing coat.
In addition to varying the angle of cuts, patterns can develop with use of contrasting natural wood colors and textures. Johnson will alternate a curly maple with a dark walnut or purpleheart. The resulting shapes are extremely pleasing to the eye — certainly that’s a result of the woodworker’s skill, but with a little help from the math of the universe. Johnson, as a new member of the League of NH Craftsmen, exhibits annually at the Sunapee Fair in August and accepts commissions.