©back panel front view
©back panel front view
After completing the base frame, I made a new base plate for my router. This base plate provides a large surface to hold the router to the back panel (E).
CUT TO SIZE. To make the base plate (F), I started with a W'-thick piece of hardboard and cut it 73/i" wide and lW long (Fig. 3).
Note: You could also use W'-thick plastic such as acrylic or phenolic for the base plate.
After the base plate is cut to size, drill a rVV'-dia. hole in the center for the router bit to fit through. The hole doesn't have to be perfectly round, so if you don't have a hole saw or a large drill bit you can cut it with a sabre saw.
Next, drill and countersink holes in the plate so you can attach it to your router. To lay out the holes, use the plastic base from your router as a template.
DRILL HOLE. To mount the plate to the vertical back panel, first drill a W-dia. mounting hole 3" down and 1" in from the right side of the base plate to align with the corresponding hole in the back of the mortising table (Fig. 3).
CUT ADJUSTMENT SLOT. Now that the mounting hole is drilled through the plate, cut a -W'-wide adjustment slot in the base plate (Fig. 3). This slot provides a simple and accurate way to adjust the position of the router.
1 cut this arched slot on a drill press by using the W mounting hole as a pivot point (Fig. A). To do this, first drill a W'-dia. hole in a scrap piece of plywood and push a W dowel into this hole. Then slip the mounting hole in the base plate (F) over the dowel.
Next, mount a 3/8M-dia. drill bit and position the plywood so the distance from the center of the dowel to the center of the bit is 93/V'. Then clamp the plywood to the drill press table.
Now drill a series of overlapping holes to create an arched slot (Fig. h)-Then remove the base plate and clean out the slot with a file.
With the slot finished, I mounted the base plate (F) to the back panel with two plastic knobs and washers (Fig. 5).
Note: You could use :W'-long hex head bolts and washers instead of the plastic knobs.
All that remains to complete the jig is a guard. Don't leave this guard off. It pro tects your fingers, and is needed to align your cuts (Fig. 7).
UPRIGHTS. To make the guard, cut two uprights (G) from W'-thick hard-board, and then cut a W slot in each upright for knobs (Figs. 6 and 7). To attach the guard plate, glue a W'-thick block (H) to the bottom of each upright.
GUARD PLATE. Next. 1 cut a guard plate (I) from W'-thick acrylic plastic IV2" wide and 7l/2" long. (Note: If you can't find W'-thick clear plastic, you can glue together two pieces of W-thick plastic.) Then I sanded a V2" radius on the two outside corners and lightly sanded the front edges.
To mount the plastic guard plate to the uprights, drill countersunk holes 011 the bottom side of the plate and screw it to the blocks (Fig. 6a).
When the guard is screwed together, position it over the bit (Fig. 7). Then mark the location of two lines on the bottom of the guard to align with the bit (Fig. 7a). Now use a utility knife to scribe the lines on the bottom of the plastic. By using the lines as a guide. I know exactly where to start and stop a cut.
Note: A complete kit of all of the hardware and plastic parts for the mortising table is available (see page 126).
To make mortise and spline joints on the mortising table, start by adjusting the router bit's height and depth (Step 2).
Then adjust the guard so the scribed lines are directly above the bit. This pro-vkkt ft reference for locating the ends of tb« mortise (Step 3).
Now use a square to lay out the joint oo both pieces (Stop i). One advantage at this jeist n that the mortises align automatically. Just mark the face side of both pieces and cut and assemble them with the marked sides facing up.
Finally, before you start cutting mortises, be aware of the correct feed direction. Because the router is horizontal, the Stock must be fed from left to right This is the opposite cf a router table.
lb cut end mortises, I use my table saws mitar gauge to support the work-piece (Step 5). On edge mortises. 1 make g series of shallow cuts betwee"
the layout lines, pulling the piece away from the bit between each pass (Step 7).
All that's left is to rip material for the splines Vs" narrower than the length of the mortise (Step 8). Then cut the splines to lengtl Ve" shorter than the combined depths cf the mortises.
To glue up the joint, "butter" the inside cf the mortises with a small artist's brush. Then, apply a thin film of glue to the spline, and clamp Step 9).
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