With this jig you can cut tapers or true one edge of a bowed board. The 36" length and 8" width for the base is what I used for cutting legs for a project but any length or width of base can be made to fit the job. Extra clamp strips should be added to longer bases for cutting straight edges.
3/4" thick plywood or particle board 36" X 8"
3/4" X 1 1/2" X 7" hardwood 2 pieces
5/16" X 4" long carriage bolts 2 ea.
5/16 flat washers 2 ea.
5/16" wing nuts 2 ea.
Cut a piece of 3/4" thick plywood or particle board 36" long and aprox. 8" wide using one factory edge to make sure it is straight for the jig base..
Using a 3/4" spade bit drill four holes at 6", 14", 24" and 30" from the left end in the center of the back of the jig base about 3/16" deep for the carriage bolt heads. Drill the holes through the board with a 5/16" bit at each of these points.
Cut two strips of 1X2 about 1/2" shorter than the width of the jig base for clamp strips, drill a 3/16" hole in the center of them.
Mark the top of the board starting 2" from the right end at 12", 24" and 32".
Push 4" long 5/16" carriage bolts through the two appropriate holes in the base, install 1X2 strips, washer and wingnut.
To use as taper jig
Set fence on saw the width of jig base. To cut a 32" long piece with a taper lay the material on the base with the ends lined up with the first and last marks, using the first and last holes for the clamp strips place scrap material the thickness of the material being cut under the other ends. With a ruler set the distance the material is on the base at each end, tighten the wing nuts, check measurements and run throught the saw.
For shorter pieces use the other holes and marks on the base.
For some widths the finished piece may have to overhang the base rather than being clamped to it.
To use as straight edge
Clamp the board into the jig using appropriate holes for clamp strips, set fence on saw to a distance that will make a clean cut through entire width of board. For boards longer than 36" make a base the length of the board.
Miter Slot Option
For a more precise jig fasten a strip of flat iron that fits in miter slot on bottom of base with countersunk wood screws, this works especially well for cutting tapers.
Rockler is now offering a ready built similar jig.