Biscuit Joiner Jig

Posted: Wednesday, February 4, 2026 at 08:26 PM | Categories: Woodworking

Back in September, I purchased a new table saw for my workshop. I have a really small shop, so for the one I replaced, I created a plywood top for it so I could use the saw for storage when I wasn't using it. I recently decided to do the same thing for the new saw; here's a picture of the result.

The distance between the table saw top and the rails on either side was about 1/2 inch, I decided to use 3/4 inch 'legs' to hold the top off of the cast iron top. This left 1/4 inch between the saw top and the cover.

Since the legs for the top were very short, I decided to do an edge on edg binding between the top and the legs as shown in detail in the following image:

I decided to use biscuits to assemble the cover, connecting the legs to the top. Since I was working with such a large piece of plywood (30" x 60"), I knew it would be difficult (although not impossible) to reliably align the bottom of the biscuit cutter with the edge of the top.

Normally, I'd hold the piece being cut vertically (using stops and clamps) and cut with the joiner flat on the table top. But when working with a piece of wood this large, that wouldn't work. I could clamp a 1" or greater piece of wood along the edge of the top and hold the top alongside that guide while cutting biscuit slots, but I knew that would be cumbersome and unreliable as well.

I decided instead to design a 3D printed jig I could use for this (and use again later if needed). You can find the jig here: Biscuit Joiner Jig Free.

The jig has an 1/2 inch overhang that covers part of the wood being cut. It also has clamping pads you can use to hold the jig in place while cutting. When you mount it to your piece, align the guide in the jig with the cut line on the wood as shown in the following figures.

Next, you place the biscuit cutter within the jig then align the cut mark on the biscuit joined with the cut line on the wood then slide the biscuit joined into the face of the jig.

If you want, not shown here, you can mark the cut line on the bottom of the biscuit joiner so its visible when the biscuit joined is fully inserted in the jig.

With this in place, I have a solid and reliable way to cut biscuit slots in the face of a large piece of plywood.

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Header image: John M. Wargo