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Router Scarfing Jig


Router Scarfing Jig

Boatbuilders often need to join boards end to end to make longer planks. Instead of a butt joint they make a long taper on each board and overlap the ends. This is called a scarf joint. One or two scarf joints are easily planed by hand, but for any quantity it’s well worth spending half an hour to make this simple jig.

The illustration shows 3⁄4-in. stock being joined with a slope of 8 to 1, which gives an overlap of 6 in. Position the plank so the end to be joined is flush with the end of the jig and wedge it securely. Make one pass with the router using a straight-flute plunge bit to remove the bulk of material. Then reset the router for a second, lighter cut, stopping just short of a feather edge at the plank end. You may wish to clean up the scarf with a few passes of a low-angle block plane.