When routing grooves, some people draw a line on the work where the groove will be, then calculate where to clamp the fence. Others draw the line where the fence will be, instead of marking the location of the groove. Both methods have obvious drawbacks. But if you make a router fence that has a hinged extension, you can mark the center of the actual groove on the work, line up the extension with the mark, then flip it out of the way to rout the groove. Make the fence out of a straight, flat 1×4. Now rip another board half the diameter of your router base (measure from the center of the bit to the edge of the base) and secure it to the fence with flat hinges. As shown in the drawing, offset the hinges so that they won’t protrude when the extension board is swung up out of the way.

James F. Dupler, Jamestown, N.Y.

Fine Woodworking Magazine, December 1983 No. 43

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