'Gizmozilla' - An Improved Router Fixture Meets Moxon-style Vise

‘Gizmozilla’ – An Improved Router Fixture Meets Moxon-style Vise

 In Jigs & Fixtures, Projects, Shop Blog

An evolving hybrid. “Gizmozilla” started as an improved router mortising fixture but has numerous capabilities. It works well as a Moxon-style vise for holding hand work. In router-fixture mode it’s well-suited for making other joints and edge profiles. Above, it’s set up to mill mortises in identical locations on two different table legs.

A perfect union between an improved router fixture and a Moxon-style vise.

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.

Gizmozilla was born.

gizmozilla tenons

Every mortise needs a tenon. The variety of setups using the clamping system and router fence makes cutting tenon cheeks a snap. For clean cuts, use an upcut-spiral bit and the plunge router’s depth stops.

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, 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.

acts as a vise

Look, it’s a vise! Want to cut some dovetails by hand? No problem. When used as a Moxon-style vise, Gizomilla’s wide clamping capability even allows for holding case sides.

stop cuts

Just stop it. Repetitive stop cuts, such as these drawer edge pulls, are simple to set up using the router stop blocks. A variety of other stopped cuts, such as mortises, are similarly done.

Build the Fixture

This fixture is easy and affordable to build; many of the pieces can come from your scrap bin. To begin, glue up two pieces of 8/4 hard maple for the beam (any stable, close-grained hardwood will work.) The length isn’t specific; it’s simply what I had – but the size has proven to be very handy. While the glue dries, set the beam aside and make some other parts you’ll need.

Go ahead and cut out the two pieces for the wooden trough at the back of the beam. Use 3⁄4″ stock the same length as the beam. Make the shoe that fastens to your router edge guide and fits into the trough. This piece will probably need to be fitted after the trough is attached to the beam so that it has no play but slides smoothly. You may need to make other adjustments to fit your particular router edge guide. Then go ahead and cut out the two feet for the beam.

Jorgensen clamps

Hold it. Jorgensen hold-down clamps are secured to the fixture with carriage bolts (with modified heads). The bolts pass through the fixture body to hold the clamps in place. Four holes allow for a variety of clamping set ups.

When the beam is dry and out of the clamps, dress and square it to final size. Use a dado stack in the table saw or rout a channel for the T-track on the top of the beam about 5⁄8″ from the front edge. The other channel is located about 1″ down from the top of the beam on the front face. Be sure the grooves are just deep enough for the T-track to sit slightly below the fixture’s surface. Next drill four 11⁄32″ holes through the beam for the bolts that hold the Jorgensen clamps. I drilled my holes 8″ and 16″ from either end, and centered 3⁄4″ up from the bottom edge of the beam. Drill additional holes if you wish.

Now take the trough bottom piece and clamp it in position on the back of the beam. The beam bolt holes must match up and continue through this piece so grab one of the bolts to mark the hole locations by tapping on it. Un-clamp the trough piece and drill it, then use it as a guide to drill the trough side. When done, line up the inner and outer trough pieces using the carriage bolts and screw them to the back of the beam.

Prepare some clamping cauls and be sure to make one as long as the beam. Make shorter ones to fit the spacing between the Jorgensen clamps.

A Bit of Metal Work

As mentioned earlier, these cauls stick to the Jorgensen clamps using rare earth magnets. To stick the magnets to the cauls, it’s necessary to attach a steel strip on the caul along its length. To make mine, I routed a 1″-wide x 3⁄16″-deep groove down the center of caul. In the groove I fastened pieces of 1″-wide x 3⁄16″-thick mild steel flat stock. Drill countersunk holes and use flathead screws to install the steel.

wood, steel and magnets

Wood, steel & powerful magnets. Because we aren’t equipped with an extra set of arms and hands, Gizmozilla’s wooden clamp cauls are outfitted with a steel strip and use rare earth magnets to hold them on the clamps.

The carriage bolts require a slight modification to fit the recessed slot in the clamps. Grind or hacksaw them, then file the heads of the carriage bolts to fit the recess. When done, cut the T- track to length and drill countersunk holes in it before screwing the tracks into the channels in the beam.

Next screw the feet to the bottom of the fixture. The feet are flush on the front but protrude to each side and to the rear. This positioning allows the fixture to be clamped to a bench and the extra depth allows the fixture to protrude past the edge of the bench when necessary.

trough on rear face

An end in sight. The end of the beam tells it all. Note the trough on the rear face used to partially house the router fence, the feet locations, clamps, cauls and magnets, and the stop block in the T-track.

Travel stops for the router are simply 3⁄4″-thick rectangular blocks made from scrap. Drill two holes in them so they can be positioned on the top of the beam and square to the front face using T-bolts with knobs or wing nuts.

The positioning stops are 1⁄4″ thick and long enough to reach past the workpiece and clamps, but are otherwise identical to the router travel stops. Angled or L-shaped positioning stops or other special stops may be made as required.

Gizmozilla grew and evolved as I built it. And as I continue working with it, the evolution carries on as I discover new and better ways to use it and expand the versatility of this fixture.

gizmozilla cutlist

Tips On Using Gizmozilla

  • Using Gizmozilla as a Moxon-style vise is probably self-explanatory, but using it as a router fixture isn’t. Here are some tips on how to use it:
  • The easiest way to position a piece for height is to simply butt the face of the piece to be worked to the bottom of the unplugged router when it is in position for mortising or tenoning operations.
  • Set the travel stops to the router base so the bit aligns to layout marks on the workpiece. Alternatively, spacer blocks can be used to set the length of a mortise.
  • Opposing pairs of mortises (such as on table legs) may be machined at the same time using multiple stop blocks. Care must be taken to maintain correct orientation of the two pieces.
  • Multiple mortises may be machined using multiple stop blocks or positioning blocks.
  • When cutting tenons or bridle joints, always position the workpiece so that the side being cut is away from the beam. When tenoning it may be best to cut the tenon a little heavy until the final length of the tenon is reached, then make a light full-length cut on each face to finish the tenon to thickness.
  • Edging operations may require that the piece be clamped to the fixture with F-style clamps rather than with the Jorgensen hold-down clamps.
  • Upcut-spiral bits work best for milling mortise-and-tenon joints; you should take light, multiple cuts using the plunge router’s depth stops.
  • If making light cuts doesn’t prevent tear-out, place a waste block at the end of cuts. In most instances, for best results it easier to guide the router with one hand and hold the router fence with the other.
  • A little beeswax or paraffin enables the edge-guide shoe to slide more easily in the trough.

Gizmozilla Cutlist

gizmozilla cutlist


Lee Valley, leevalley.com or 800-871-8158

2 ■ 48″-long T-track, #12K79.28, $15.50

8 ■ 11⁄2″ T-bolts, #12K79.71, $3.70 (pack of10)

2 ■ 1″ T-bolts, #12K79.70, $3.20 (pack of 10)

10 ■ T-bolt knobs, #00M50.10, $1

4 ■ 3⁄4″ rare earth magnets, #99K32.11, $8.40


Woodworkers Supply, woodworker.com or 800-645-9292

4 ■ Jorgensen 1623 3″ hold-down clamps,#125.030, $14.69

Prices and availability subject to change.

This article appeared in the October 2012 issue of Popular Woodworking magazine.

Plan: Download a SketchUp model of Gizmozilla.

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