This product is designed to work with plunge routers. While it may be possible to use it with fixed base routers, I think it would be tricky and might compromise the tool’s built in accuracy. A guide for selecting mounting holes for many routers is printed on the back of the shipping card, and was easy to follow. The product includes a pin and insert to allow centering on your router’s base. n
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In use, some things worth mentioning: It is imperative you attach your workpiece to a substrate, both inside and outside the selected diameter circle you’re cutting so as the cut is completed, nothing moves. Good quality double sided “turner’s tape” worked well for me. n
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The product includes a 1/8″ pin that goes through the jig and into the center of your workpiece. Might also be a good idea to drill into the substrate a bit as well, a touch more insurance the center piece doesn’t move and ruin your cut.n
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Be aware you’ll be turning the entire router around the central pivot, so leave yourself some room to walk around it so you can keep a good grip on your router’s handles. Also, it pays to use your plunge router’s stops to take partial depth cuts. I went through half inch hardwood plywood with a solid carbide Freud bit in three passes, leaving only about an eighth for the final pass to minimize forces on that turner’s tape I used to hold things together, and had no problems.

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Bought one of the $180 Routers to go with this Jig, which isn’t calibrated for the provided scale – nothing simple math can’t take care of. Also have gone through 4 X $15 bits in short order. They keep breaking at the stem. It is imperative that you keep the router flat with constant even down pressure while using this product. Overall, I don’t know a better way to get a near perfect circle.

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This product works ok if you need a hole that is not too accurate. But if you need a 5″ hole this thing may cut .03 under and there is no way to adjust it to make up for it. I needed to fit a steel plug into a hole and this tool cannot make a hole for it. I’ll probably end up having to “egg shape” the mounting screw holes so I can fine tune my hole size. Also it would be very nice if the hole size markings were on both sides of the plate. As it is, the sizes are on the bottom making it difficult to see where to put the pin.

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I used this jig to cut holes for some speakers I built. It works really well to hold the router in a circle pattern. Just a couple things to note:n
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1) If you drill the pilot hole for the 1/8″ pin that fits into the jig at exactly 1/8″, then it’s hard to get into/out of the material you are cutting. But if you make the pilot hole 1/64″ larger, then the pin will fall through the hole and out of the jig. I ended up drilling the pilot hole 1/64″ larger and putting masking tape below the hole to keep the pin from sliding through.n
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2) The jig screws to the bottom of the router base. So some of the pin holes for smaller diameter circles are blocked by the base of the router. You can still insert the pin in them from the bottom, but it only goes in the width of the plastic and can fall through the pilot hole or slip out of the jig if you’re not careful.n
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Other than that, it’s a great help to cut perfectly round holes.

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Have used this jig for home audio subwoofers and speakers. The first time out you will want to practice on scrap. This is just to get the feel of it. Use a cheap speaker for measurements on both the cut out as well as the dado to flush mount. n
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You should invest in a drill press (plenty of $120 ones out there). This will make all the difference in a truly uniform edge as the pivot pin will be straight in and not at a slight angle that is inevitable with hand drilling. Remember even a small difference from the pivot pin being perpendicular to the piece you are routing will make a difference.n
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Love this jig. It didn’t cost me $39, it made me $$.

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