By Kenneth Speed
This fixture, which I’ve christened “Gizmozilla,” grew out of my general dissatisfaction with the methods available to small shops to cut mortises. At one time I used a small hollow-chisel mortiser but I never found the results satisfactory. I tried an open-sided box jig for router mortising, but by the time I had everything in position and clamped I was completely out of patience with the whole procedure. Finally, I resorted to drilling out mortises on my drill press and doing the final chopping out by hand. While I was generally happy with the resulting mortises, the process was far too slow.
Then I happened on an article in an old woodworking magazine that described a basic router mortising fixture. It was a wooden beam with an attached channel for the router edge guide; it used Jorgensen hold-down clamps to secure the workpiece. The author nailed stops to the beam to limit router travel. While the basic idea was sound, it seemed less than fully developed. Nailing stops to something I’d just worked hard to make smooth and square seemed a little crazy, so I added T-track and moveable stops.
I also added wooden clamping cauls of various lengths outfitted with steel bars and rare earth magnets to hold them to the clamps while allowing for some adjustment. The cauls and Gizmozilla’s 4′ length adds to its flexibility.
I soon realized that by adding the lower feet I had a variant, and possibly an improvment on, a Joseph Moxon-style vise. The feet raised the fixture slightly and allowed me to position the face of the fixture forward of the edge of the bench.
Gizmozilla was born.
When the fixture is paired with a plunge router equipped with a guide fence, the adjustment features allow Gizmozilla to excel at numerous functions. It enables a woodworker to make repetitive mortises in precise locations on multiple parts such as table legs, or make multiple mortises on one part by setting additional router stops. Again, the adjustability of the router fence and depth of cut enables Gizmozilla to be used to cut tenons as shown above at top, or half-lap joints and bridle joints. I can also route edge profiles by clamping stock to the side of the fixture, as long as the cut is shorter than the fixture’s overall length. Similarly, edge-routing doors and most tabletops and making stopped cuts, such as routing finger pulls in doors or drawer fronts, are all quickly accomplished. For many operations, Gizmozilla is easier and more intuitive to set up and even safer to use than a router table. I’m still discovering more uses for this fixture.
Gizmozilla also performs as a convenient and adaptable Moxon-style vise. The beam provides both a vertical and a horizontal surface at right angles to one another so marking out and cutting dovetails is quickly accomplished. The size of Gizmozilla enables me to clamp multiple pieces side by side (drawer sides for example) or to dovetail wide carcase sides. Pieces can be clamped down to the top of the fixture to make it easy to test-fit and adjust dovetailed components. The addition of T-track to a Moxon-style vise allows me to set angled stops for easier dovetailing.
Video: Find out where the glue goes inside a mortise-and-tenon joint.
To Buy: “Getting Started with Routers” DVD.
Plan: Download a SketchUp model of Gizmozilla.
In Our Store: “55 Best Shop-Made Jigs” CD.
From the October 2012 issue #199
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