By Gary Rogowski
It was the 1970s. I was a young, lost woodworker out cruising the West Coast in search of inspiration, mentors, cool old tools and furniture to study. I found legendary furniture maker Art Carpenter at his studio in Bolinas, Calif. He showed me two things. One was the first and loudest router table I ever saw: a router hanging under a piece of plywood perched atop a 55-gallon drum. He also showed me how to cut coves on the table saw. What the heck was this? Curved shapes cut on a table saw? I was mesmerized by this bit of woodworking wizardry.
Most people think of the table saw as a machine capable of cutting only in a straight line. Shove miles of wood through it to rip lumber to width, break down sheets of plywood, crosscut boards to length or make the occasional miter or angled cut. Noisy, loud, brutish. What is amazing to discover is that the saw can also make curved shapes if you know how to approach it.
Let’s consider blade geometry first. You make a normal rip cut on the saw with the stock pushed straight into the blade. You cut a groove on the table saw with the grain but not through the full thickness of a board. Now imagine coming at the saw blade not straight on as usual, but at an angle with the blade set just barely sticking out of the table. If you can, imagine coming in at 90˚ to the blade. Keep imagining that, after raising the blade in a series of passes that take small cuts, you’ll finish with the blade raised to its full height. A frightening thought, really – and one you shouldn’t try.
But if you could make this cut, you would produce a profile that matched the arc of the blade projecting above the saw table. Well, back off this 90˚ angle and imagine your wood approaching the blade running against an auxiliary fence. You’ll make a series of passes with the stock and raise the blade ever so slightly each time. This is how you make a cove cut. The shape you get depends entirely upon the angle that you set your auxiliary fence to the blade and the angle or tilt of the blade itself.
Set up the Cove Cut
Your first task is like many woodworking jobs; you can’t move forward until you make a jig. This one, made from scrap wood, is simple to build. Make up a set of adjustable parallel arms that open to a width of about 6″. The width you set with these parallel arms helps you find the correct feed angle to the blade. I make my parallel arms from two straight ½”-square sticks about 16″ long. These are fastened to two 6″ arms. The arms must open and close easily and remain parallel when adjusted.
Video: Watch the author demonstrate his technique.
In Our Store: Get our 76-page Essential Guide to Table Saws.
Web Site: Visit Gary Rogowski’s Northwest Woodworking Studio site for information on classes and to view a gallery of his work.
From the April 2013 issue #203
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