Creating a parallel straight line is easy – just move the straight edge over the desired width of the piece. On a curve of uniform radius you just adjust the compass or trammel points and create a perfectly parallel line. Neither method will work on a piece that has a changing radius curves or an S-shaped piece.

Mickey Callahan uses a shop-made tool to create a parallel-sided template for his gooseneck molding template, but you can use the tool and the technique for any kind of shape. He employs a disc, whose radius is the same distance as the desired width of the template or workpiece. A nail in the center of the disc runs along the existing curved edge while a pen on the outside of the disc creates a line exactly parallel to the existing curve. It’s that simple.

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Bandsaw your disc. Calculate how wide you want the workpiece to be, set a compass to that distance and draw a circle on some 1/8-in. thick MDF. Bandsaw just outside the line.

 

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Smooth the edge. Use a brad through the center of the disc to secure it to a piece of scrap wood with the edge overhanging by about an inch. Clamp the scrap to the table of a disc sander and pivot it in until the disc is sanded just down to the line. Secure the clamp and then turn the disc to sand it flush with the line all the way around.

 

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Run the brad along the existing finished edge of the template and at the same time hold a pen against the point of the disc furthest from the brad. This will create a perfectly parallel line. Photo credit: Mark Schofield.

Photos: Mark Schofield

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