Synopsis: The best tool for creating a curved surface across the width of a board is a coopering plane. Clark Kellogg shows how he made his version, which is based on James Krenov’s classic bench plane design. First he shapes the sole to match the curve of the blade, then grinds and sharpens the blade with a hollow-grind.

I love using coopering planes. The long, curling scoop-shavings they make, and the slightly burnished, rippled surfaces they leave are incredibly satisfying to the touch. They can be used for a few different tasks, such as texturing a panel or creating a profiled molding, but their raison d’être is making curved surfaces across the width of a board. And, more often than not, they are the best way to create such a curve.

Although using a coopering plane, with its curved blade, can seem intimidating at first, in practice the…