Tricks of the Trade: Shop-made Circle-cutting Tool

By Bill Wells
Pages 14-15

I often need to cut an arc or circle for a template or gasket. In the past, my results using a compass and scissors were far from the smooth shape I hoped for. Recently, I needed to cut a precise, smooth circular arc in a sheet of veneer, and I realized my old methods were inadequate. In addition to the arc looking ragged and uneven, the thin veneer would break when I attempted to cut it. I needed a better method.

I came up with a circle-cutting tool that uses a rotary blade similar to the blade used in some office paper trimmers.

The rotary cutter blade is 28mm (1.10″) in diameter with a 5mm (3⁄16″) mounting hole. A set of two blades is available at office supply and fabric stores, or online under “paper trimmer blades.” The blade is attached to the end of a 1×2 board using a 3⁄16″ x 2″ hanger bolt, with two 3⁄16″  x 1″ fender washers supporting the blade, (one on each side) and a standard 3⁄16″ washer between the board and the first fender washer. Two 3⁄16″ nuts hold everything snugly, but allow the blade to rotate. I drilled holes in the board at 1″ increments and used a nail through the holes, driven into 3⁄4″ plywood underneath, as a pivot point. The blade extends below the 1×2 board about 3⁄16″.

With this circle cutter, it is best to make several light cuts.

When the tool is not in use, I wrap a piece of duct tape around the blade to protect it.
It works great.

Tricks Online: We post tricks from the past and film videos of some Tricks of the Trade in use in our shop. They’re available online, free. Visit popularwoodworking.com/tricks to read and watch.

From the December 2012 issue #201
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