Biscuit Joinery for Beginners: A Waterfall Box Adventure

Written by Tim

This article documents my first experience using the Woodstarter biscuit joiner to build a waterfall box. Along the way, I share the process, useful tips, and the lessons I learned. If you are a beginner interested in biscuit joinery, read on for a realistic and detailed walkthrough.

Recently, Woodstarter sent out a call for woodworkers who might be interested in trying out one of their tools. When I saw that one of these was a biscuit joiner, I knew I had to sign up. I build a lot of boxes, mostly with miter joints. Miter joints are infamous for their weakness, so I am always looking for ways to keep the polished look of a miter while making it stronger. A biscuit joiner seemed like a viable option.

Fortunately, the folks at Woodstarter thought so too, and I soon received my very own biscuit joiner. I have never used a biscuit joiner before, so this article is going to talk about my experiences learning to use the tool and some of the lessons I have learned. Along the way I will walk you through the process I used to make a box, some of my mistakes, and what I learned from them.

Initial Setup and First Attempts

A biscuit joiner is a pretty simple tool. It does one thing: carve a slot that will accept a biscuit of a pre-defined size. Biscuits have a standard thickness, so the only thing to adjust is the depth of the cut. The Woodstarter joiner has a simple knob that you can use to set the depth. Just choose your biscuit size: #0, #10, or #20 and go.

I did check to be sure that the cut depth was appropriately calibrated, and it was spot on. A hat tip to George Vondriska at the Woodworkers’ Guild of America (wwgoa.com) for his very helpful videos on getting started with a biscuit joiner (Not Sponsored). The depth assessment and miter trick described below are from his videos.

After making a bunch of holes in some scrap wood, I decided I was ready to try a miter joint. The walls of most of my boxes are pretty thin, usually no more than 3/8 of an inch. The height of those side panels is usually around 3 inches or so. This presented a problem, as the Woodstarter joiner (and every other joiner I have seen) has a big opening in the support frame so you can line up your cut. Of course, it is more than 3 inches wide. Like any good woodworker, my first thought is “I need a jig”.

Building a Jig for Thin Stock

Using painters’ tape and super glue to make quick-and-dirty double-sided tape, I added a thin board to the underside of the joiner frame and adjusted the frame height to keep the kerf in the center of my board. Since I wasn’t able to see the center line on the frame anymore, I added a guide to one side. If I held a 3-inch-wide piece of wood against this bar I knew I’d hit the center.

Time for a test: I ended up with a nice slot on both the edge and face of my board. Even with a #0 sized biscuit the slot was too deep. Back to the drawing board. This went on for a while and I ended up with a pretty fancy jig that didn’t really work.

By this point I’d made enough holes that I was feeling confident I could make this work with a thicker board. Time for a real project!

Planning and Preparing the Waterfall Box

The Waterfall Design Concept

I’d been seeing a lot of videos on YouTube about ‘waterfall tables” and wondered if the same approach would make for a good box. When possible, I try to wrap the grain around the sides of the box as seamlessly as possible. Could I do something similar with the top, such that the grain flowed from the top down to one or more sides? The short answer is ‘Yes’, but not without some challenges.

I have a piece of walnut that would be perfect for this kind of design. It has an interesting concentric grain pattern that stretches far enough to flow down both sides of the box. To fit the entire pattern, my box will need to be at least 8 X 12 x 4. Not coincidentally, 4 inches is also enough to span the joiner frame without extra supports. I decided to make the walls of the box ½ inch thick to make it easier to use the biscuits in the miter joints.

Resawing and Plank Gluing with Biscuits

Now to the first area where the biscuit joiner was helpful. My walnut board was a bit over 1 inch thick. I didn’t want to waste a bunch of wood by planning it down to ½ inch, so I needed to resaw. I have two resawing options: table saw and bandsaw. I also have a small garage shop, so neither of these can take a board wider than 6 inches.

Lightbulb moment: I can cut my walnut board into smaller-width planks and then add contrasting wood stripes as design elements to hide the kerfs. Since grain alignment is very important for this project, I can use my shiny new biscuit joiner to make sure the planks stay aligned when I glue them back together. High fives all around!

So, I prep my board and chalk out all of the various cuts, alignment marks, etc. to help visualize how the box will take shape. I am not going to use these lines for cutting - I’ll use measurements for that, but seeing them on the wood helps me visualize the process. You will notice that I am purposefully making the board wider and longer than I need. Mostly this is to help with planer snipe, but it does give me some wiggle room.

I decided to use cherry for the other sides of the box, so I will use it for the stripes as well. I made the stripes ½ inch wide. In retrospect I should have gone with a thinner stripe, say ¼ inch, but I was a little concerned about even the #0 biscuit kerf cutting too deep. On the other hand, ½ inch is a good width if I ever want to put inlay or other design in the cherry.

A First-Timer's Mistake: Registration is Key

Now it is time to cut the first set of biscuit kerfs. I have laid out where I want them and chose to only put 2 biscuits on each side, keeping them in the area I have designated as the top of the box. Again, I probably could have used bigger biscuits, but I stuck with 0s. The kerfs on the walnut side of the first glue-up were great, and I had an awesome idea how to make it easy to line up the kerfs on the cherry side - line the cherry pieces up with the layout marks on the walnut and then flip them over. Use the marks on the walnut to locate the joiner and have at it!

It's only when I glue them up that I notice that something is off. The tops of the cherry and walnut pieces are not lining up. Oh, I think, it must be because I only used 2 biscuits. So, I added 2 more along the parts that will become the sides (which will haunt me later).

One of the things George talks about in his videos is the importance of always registering the biscuit joiner to the same side of each piece. My super-awesome time-saving trick completely ignored that advice, to my disappointment. Fortunately, the walnut pieces ended up being pretty much at the same level, but the cherry pieces stuck out on one side were recessed on the other. This meant more time in the planer. I had cut them thick (5/8 inch) to start with, knowing that I would need to do some planning. But by the time I was done smoothing everything I only had about 3/8 inch left. Lesson learned.

Box Construction: Miter Joints and Assembly

Cutting Rabbets and Miters

Once the walnut piece was glued back together and cleaned up, it was time to cut it to its final width. However, before cutting the sides off the main piece, I added the rabbets on each side that I would use to hold the cherry sides. Doing it while the board was in one piece made it much easier.

Since I am too lazy to swap out a dado blade in my saw (I’d have to change the brake too, and that’s a pain), I opted for a flat-toothed ripping blade and set the blade height at 3/16 (half the height of the top/sides). I set my rip fence to the width of my board and then moved it in so the so the inside edge of the blade is the width of my side pieces (3/8) from the board edge. This cuts the innermost edge of my rabbet.

Since the rabbet is the same on both sides, I just need to flip the board around and make the same cut on the other side. Then I move my fence out a little less than 1/8” (blade width) and cut both sides again. I repeat until I have 2 nice rabbets.

Cutting the Waterfall Miter Joints

The next step is to cut the sides off and create the miter joints for the waterfall. I am going to lose some wood here because of the blade kerf, but I will try to minimize it. Accuracy is important here, as the joint needs to be exactly 45 degrees. I use a digital angle meter and follow that up with the 45-degree side of a combination square. Test cuts are never a bad option.

Now, without changing anything in my setup, I take one of the sides and flip it over (top-down on my saw). I line it up so the top of the angled blade just kisses the ‘top’ of the board. I want to end up with the side panel and a little triangle of wood.

It is easiest to do this in multiple passes. I start shy of the top of the face and sneak up on it, since the more I cut into the top of the face, the more noticeable the kerf will be. Then I repeat for the other side.

Installing the Bottom Panel

I also need to cut slots in all 4 sides to hold the box bottom. To accommodate wood movement, I don’t glue in the bottom (unless it is plywood). Instead, I cut dados in all four sides and use them to trap a panel in place. Once the box is glued, the panel will stay in position but have the flexibility to shrink and grow without destroying the box.

I like to use a ¼ inch hardwood panel for the bottoms of my boxes. I cut them to be at least as large as the box width and length, and will trim them down later. It helps to have the panel ready to go when making the dados, as it is easier to cut dados to fit the panel than adjust the panel to fit pre-cut dados. I set my fence 1/8” away from the blade and set the blade height to 9/16 inches (half the width of the side piece). Setup blocks help with this, or you can use a drill bit (say, in case you lose your 1/8” block).

I cut a dado on the inside of the bottom of each side (on the end without the miter, on the side the end grain of the miter faces). Adjust the fence to widen the cut until the panel just fits securely. You shouldn’t have to force it, but it also shouldn’t fall out if you turn the board over.

Final Glue-Up and Curing

Now I am ready to cut biscuit slots in our miters. Following George’s advice (as mentioned above) I taped the outer faces of the top and sides together with the miter edges lined up exactly as I want them. This does 2 things: it gives me a 90 degree surface to register the joiner against, and it ensures I am always registering against the same side of both pieces.

I don’t want to set the joiner to cut in the middle of the boards, as that will leave me with little sunroofs in my box sides. Instead, I want to get the joints as low as possible on the miter without cutting the inside face. This will give me the most wood to hold the biscuit and should be enough for a #0 biscuit without cutting through. It took some trial and error to find the right position.

The number of biscuits depends on the size of the box. I used one per side but probably could have used two.

Finally, it is time to glue up the sides with the biscuits. The biscuits really help keep the joint aligned while you are gluing. I ran into a little bit of trouble with a low slot, so I glued my sides one at a time so I could do some repair work. Clamping is easier if you do both at the same time, as you have to be very careful you don’t damage the miter on the other corner (That will sand out, I think…).

Finishing the Box: Cutting the Lid and Applying Finish

Cutting the Lid and Another Lesson Learned

Once the glue has dried, I have a wooden cube. Nice to look at, but not very useful. I need to cut the top off to make it into a box. Before I do this, I give the box a good sanding with 80 grit paper. My goal is to smooth out the lines, remove any construction marks, scratches, snipe, etc. This isn’t a finish sanding, just one to get the sides smooth so I can make a straight cut when separating the lid from the bottom.

It is lid cutting time, and here is where my decision to use biscuits on the sides came back to haunt me. Depending on the box, I usually make my cut approximately ¾ inch down from the top. Wouldn’t you know it, there is a small piece of biscuit showing on both parts of one side. Lesson learned: Remember you are going to cut the top off and include this in your biscuit location plans.

I have a small bandsaw and I have trouble getting a straight cut on it (I blame the tool but secretly know the real cause). So I use my table saw to cut the lids. I lose more wood, but I know the cut will be straight. My approach is to set my fence to ¾ inch and position the box so the lid rides between the blade and the fence.

Finishing and Final Thoughts

The parts of the box and lid that were just sawed are likely to have some rough spots, the aforementioned gaps, etc. I have a drum sander (favorite new toy) so I just run them through a couple of times to smooth everything out. In times BDC (Before Drum Sander) I used a board with sheets of sandpaper glued to it, with a different grit on each side. For smaller boxes I put the sanding board on the workbench (my table saw) and move the box around. For larger boxes I move the sanding board, making sure to always keep it in contact with at least two box sides. This really helps get a level finish. Any divots or other irregularities will be painfully obvious when the box lid is closed.

For the most part this is habit because my favorite finish isn’t that susceptible to dust. I like to use Tried and True Original (also Not Sponsored), which is a combination of linseed oil and beeswax. What I like best is that when dry it doesn’t feel like there is anything between you and the wood. As an oil finish, it soaks into the wood without creating a ‘plasticky’ layer on top of it like urethane does. Plus, it is food-safe and doesn’t smell. You just wipe it on and then come back an hour later and wipe off the excess. I usually do one coat on the inside and bottom and 2 - 3 coats on the rest of the box.

And here are a few pictures of the final product.

Looking back on this project, I’m really pleased with how the biscuit joiner helped improve alignment and ease the glue-up process. But I also made some classic first-timer mistakes—like not accounting for lid cuts when placing biscuits and ignoring the rule about registering off the same face. Those missteps taught me more than getting it perfect would have.

If I were to do it again, I’d take more time laying out my cuts and dry fitting each step. I’d also experiment with smaller biscuits and thinner panels to expand what’s possible with delicate joinery.

Most of all, this project reminded me that trying a new tool doesn’t have to be intimidating. With a little patience (and a lot of scrap wood), you can level up your skills and have something beautiful to show for it. The biscuit joiner has definitely earned a permanent place in my shop.

🧰 Summary Tips for Using a Biscuit Joiner on Box Projects