Is a biscuit joiner completely useless?

Years ago, back in the 1990s and early 2000s, a biscuit joiner became a very popular woodworking tool. It seemed like every woodworker had one. I’m pretty sure the reason for their popularity came down to two words: Norm Abram. 

Back before YouTube, the only woodworking shows were on TV, and The New Yankee Workshop was the most popular. Norm had a huge shop filled with super high-end tools . . . similar to the shops on most YouTube woodworking channels today. One tool he was really fond of using was his biscuit joiner. This was an affordable, handheld power tool that allowed woodworkers to make strong, invisible joints easily. A lot of us rushed out and bought biscuit joiners. Basically, it’s like making floating tenons. 

Or is it?

Well, as much as I admire Norm Abram, a biscuit joiner may be one of the most useless power tools you can own. I know this because I own one. And I have used it. But mostly I forget about it. 

Well, to be fair, biscuit joinery does have some limited uses, but probably not enough to justify its purchase, and I don’t want you wasting money on tools that are just going to gather cobwebs. 

But first, if you’re new to woodworking, or if you’re a maker, you may not even know what a biscuit joiner is. 

The tool has a little saw blade that plunges into wood, creating a slot. You make a slot in each piece of wood you want to join, then add some glue and drop in one of these little biscuits. These things are compressed wood, and the glue causes them to expand a little, creating a joint. 

So the problem here is not whether it works or not; it’s that its effective uses are very limited. One of the most common uses for biscuits is edge-joining panels—say, for making a table top. Again, watching Norm Abram gluing up panels this way pushed me into buying a biscuit joiner.

Eventually, woodworkers came to realize that biscuits add basically zero strength to an edge joint. Just gluing up boards edge to edge is super strong on its own. 

Some woodworkers argue, “Well, okay . . . but biscuits are useful to help keep boards aligned when edge joining.” I used to think that myself, but I’m not sure if this does anything either. There’s so much play in a biscuit joint that it hardly draws the edge seams together flush. If you’re going to edge-join boards, you will need to use cauls to keep them flat anyway. 

For any assembly where you’re joining the long grain of wood . . . in other words face grain to face grain, or face grain to edge grain, or edge grain to edge grain . . . glue alone is fine. The wood will break before the joint does. 

The main purpose of any type of joint is to connect the end of a board to another board. End grain is very porous, and glue alone will create a very weak connection. Dealing with end grain is one of the fundamental challenges in woodworking. This includes plywood edges, which are also fairly weak when only glue is used. 

So these points of connection need some sort of reinforcement—either mechanical (like using screws or nails), or by shaping the wood in a way that physically holds the pieces together (like dovetails), or by cutting the wood in a manner that allows face grain to contact face grain (such as a lap joint or a box joint). 

In my Woodworking for Mere Mortals method of woodworking, I prefer pocket-screw joinery in projects where they won’t show, and lap joints where they will show. But my go-to method of joinery is the dado joint. Even though it isn’t technically a long-grain-to-long-grain joint, there is enough surface area for the glue to hold the pieces, and the shape makes alignment a snap. 

If you are building something out of solid lumber that will be subjected to a lot of stress, such as a rocking chair, I doubt you will find any joint stronger than the mortise-and-tenon joint, which is beyond the focus of this channel.

If you’ve got about $1500, there’s a simpler way to make mortise and tenons by using a Domino Joiner. There is only one German tool company that makes it, so don’t expect to find any affordable alternatives. It cuts deep holes into the wood that the wood “dominoes” are glued into. These are called floating tenons, and they are arguably as strong as traditional mortise-and-tenon joints. They are great for professional woodworking environments, but the tool’s cost places it outside the mission of Woodworking for Mere Mortals.

A similar, but much weaker method is to use a dowel-joining jig. These have never been extremely popular among woodworkers because they can be notoriously fussy to set up. Plus, the dowels are usually shorter and thinner than dominos and not nearly as strong. But they’re relatively affordable and some people swear by them.

And that brings us back to the biscuit joiner, which is basically a floating tenon, only crappier. The biscuits are just too small to provide much additional strength to a joint. 

So where are biscuits effective? 

Well, I think they are a pretty good way to strengthen up miter joints, which can be fairly weak with glue only. But a biscuit joiner cuts pretty wide slots, so you can’t use it on narrowish boards. 

You could use it to cut slots in the corner and glue in a spline, but that’s a little tricky. And making your own spline-cutting jig is pretty easy and it’s fun to use. 

And if you’re making miters that aren’t going to be subjected to a lot of stress—say, a picture frame that just hangs silently on the wall—you can get away without any reinforcement to the miters at all. Or maybe corrugated joint fasteners on the back.

Biscuits can be used to join the ends of boards to edge or face grain. They will definitely provide more strength than glue alone, but not a lot. If your boards are too narrow, you can reinforce the joint by adding the biscuit on the back side of the face. But again, I would prefer to just use pocket screws, dados, or rabbets. 

For cabinet-face frames, biscuits are a viable option and might be helpful for attaching them to the edges of a plywood cabinet. But you really don’t need them at all for this use.

There are some other uses, but I don’t find any of them to be a compelling reason to own a biscuit joiner. 

Bottom line? Even beginning woodworkers can learn simple and more versatile techniques than biscuit joinery. And if you’re looking for an effective, proven, step-by-step method for learning woodworking that cuts through all the BS, I want you to head over to theweekendwoodworker.com and check out my online courses. You can build your first project this weekend with absolutely no experience and no biscuit joiners. 

Thanks for watching! 

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