Paired with a plate joiner, the jig shown above will reduce the setup time needed to cut slots for biscuits in a series of workpieces. Build the jig from %-inch plywood, except for the barrel support, which should be solid wood. Refer to the illustration for suggested dimensions. Screw the handle support to the base and attach the handle brackets, spacing them to fit your tool. With the plate joiner resting upside-down on the handle support, butt the barrel support against the motor housing and outline its
shape on the stock. Bore a hole for the barrel and cut the support in two across its width, through the center of the hole. Screw the bottom part to the base and fit the other half on top. Bore holes for hanger bolts through the top on each side of the opening, then drive the bolts into the bottom of the support. Use wing nuts to hold the two halves together. Finally, screw the auxiliary table to the joiner’s fixed-angle fence. (It may be necessary to drill holes in the fence for the screws.)
Cutting the slots
Secure the plate joiner in the stand and clamp the jig base to a work surface. Set the fence at the correct height and, for repeat cuts, clamp stop blocks to the auxiliary table to center the workpiece in front of the cutter. For each cut, put the workpiece flat on the table and butted against the joiner’s faceplate, then turn on the tool and push the stock and the table into the blade (left).