Router Compass and Ellipse - Canadian Woodworking Magazine

Tool Review


Router Compass and Ellipse

A lot of woodworkers get intimidated with the idea of cutting circles, let alone arcs and ellipses. However, it’s simple to rout out a large circular or elliptical tabletop if you have the right equipment. Now, with the Router Compass and Ellipse J/A router accessories from Trend Machinery, you can say goodbye to the square top!

The Router Compass is a straightforward accessory. Although most convenient to use with a plunge router, it will mount to any router. The Router Compass is made of ¼” thick clear acrylic, and has a 1.18” (30 mm) center hole. You’ll have to drill and countersink holes in the underside of the compass to fit your router. The compass comes with a pin centre that you can press into your stock, and a ⅛” rod centre, which you insert into a predrilled hole in your stock. I find the rod centre most convenient to use. You can rout circles from 4” to 24” diameter. Adjustments are a snap with the graduated scale printed on the arm of the compass.


I mount the compass on the underside of material that I’m routing, and take shallow, controlled cuts moving my router counter clockwise. I rout no more than ⅛” deep each pass. I’ve had great success using 2-flute up-cut spiral bits. Even so, when the bit runs against the grain you might get a bit of tear out, which will need some sanding. Once you’ve cut the circle you can change bits and apply a decorative edge. All in all, this is a very useful product to have in the shop.

Cutting ellipses is just as easy with the Ellipse J/A. This accessory enables you to cut circles and ellipses as well as circular and elliptical arches from 21 ½” (550 mm) to just over 70 inches (1800 mm), and will accommodate any brand of router. The Ellipse comes with a 1” thick Duralumin cross frame (an alloy of aluminum, copper and magnesium), 2 sliders that ride in the channels on the cross frame, a metal connector plate that attaches to your router, two 20” metal arms, along with the requisite tools and instruction booklet.


You will need to attach the metal connector plate to a base; I used an 8” by 14” piece of ¾” ply (my first try was a piece of ¼” hardboard, which broke away from the connector plate rather quickly). You also attach your router to the plywood base. Placement of the connector plate and router on the ply base is not crucial. Just remember to countersink the screws in the bottom of the base; else you will risk scratching your work piece. I put a couple of strips of low friction tape (Lee Valley catalogue #25U04.01) on the bottom of the base; it slides like water off a duck’s back.

Again, as for the Router Compass, a plunge router would be the tool of choice here. However, I used my non-plunge router with no problems. All that remains is to slip the two sliders into the channels on the cross piece, then connect one or both of the metal arms to the connector plate and to the sliders. You’re now ready to use the Ellipse. A set of clearly written instructions shows you how to arrange the two sliders to set the maximum and minimum axis (i.e. length and width) of your ellipse.

I used the Ellipse to make an elliptical cherry table top (⅞” thick by 33” wide and 46” long). The idea of routing through ⅞” of cherry didn’t appeal to me, so I made a second ply base and attached my Porter Cable jig saw to it. I cut about ⅛” outside the final cut line. It went surprisingly quickly, and I think it kicked up less debris than the router would have done and it also saved wear on my router bit. I then attached the router to the Ellipse and made my finish cut using a ½” spiral up-cut carbide bit. You could also attach a portable oscillating spindle sander to the Ellipse to speed up your final edge sanding. When routing with the grain the finish was perfect; where I routed against the grain there was a bit of tear out that required some hand sanding.

Remember to turn your table top over and rout on the underside. You can screw the cross frame to the underside of your table or, as I did, you can attach it with double-sided tape.

I wouldn’t recommend back cutting with your router when using the Ellipse. When using a fixed-based router you want to be careful when the router bit first makes contact with the tabletop, as the bit may grab the wood. There is enough flex in the metal arms that you can lift the router slightly above your work piece, switch the router on, then bring the router to bear on the work piece.

The Ellipse is an excellent product that is very easy to use. It’s also durable. I accidentally dropped the cross frame on my concrete floor and it came out none the worse for it. For those of you who will be making an occasional circular tabletop, the Router Compass is the way to go; if woodworking is your life, then the Ellipse will be a real lifeline. Certainly, if you will be cutting any number of circles or ellipses, it’s a worthwhile investment that will save you both time and money.

Trend Machinery ( is out of England, UK. For information you can contact their North American Sales Manager, Terry Cole, at 1-859-485-2080 or . You can also order either of these router accessories direct from Trend. The Router Compass is priced at $74 CDN while the Ellipse is competitively priced at $371 CDN. For more information, or to order, contact Trend Machinery. 


Carl Duguay 2
CARL DUGUAY is the web editor for Canadian Woodworking & Home Improvement Magazine

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