Biscuit Joinery, Just Because

A young lass I’m trying to impress wants to make a rustic shelf to hold books. She wants it to look and function sort of like a small bench. In other words, there’s no casework involved. The shelf would rest on a metal frame on the floor.

Rather than buy a wide, somewhat expensive piece of hardwood with a live edge or two, we decided to source a reclaimed pine beam and find a way to resaw it down the middle. Our plan is to then edge join the two boards to form a wide shelf, leaving the outer edges rough for the desired character.

It won’t be quite the same rusticity as a live-edge piece, but I think it will look pretty good.

The only question remaining is how to successfully edge join the boards. They are going to be about 4 feet in length and maybe 2 inches thick. I have pointed out that planing the edges perfectly flat and square is super-important. Then we’ll need to choose either biscuit joinery or some other form of simple, solid edge joinery to bring the boards together.

When this question came up, the young lass I’m trying to impress asked me, “Can’t we just use some kind of metal cross-braces and screw them into the top and bottom of the shelf?”

I responded no. She asked me why not.

It was one of those moments when you want to say, “Just because.” I was caught in my own knowledge gap. I’ve always thought biscuit joinery and dowel joinery are the best options for simple edge work like this, but I was never told why. I also have assumed that metal cross-braces extending across the width of the board will cause the board to crack. (Wood expands mostly across its width.) But here again, I don’t know the facts and have never tried it myself.

What do you use for edge joinery on boards of this size? Have you ever tried metal cross-braces? How did that work out?

No matter what joinery methods you use, you’ll find some amazing tips from a true master in our latest DVD release, “Joinery Master Class with Frank Klausz.” Buy it today and build your skills! Frank is a man who never says, “Just because.” He always gives you solid reasoning to help you remember the right methods!

Dan Farnbach

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Dan Farnbach

About Dan Farnbach

Dan apprenticed and worked in two professional shops during the years after college. But sweeping shop floors only goes so far toward learning woodworking. These days Dan is online editor for Popular Woodworking, and is learning new skills every day. He divides his time between Boston and Maine.

16 thoughts on “Biscuit Joinery, Just Because

  1. JWatriss

    -Biscuits and dowels are ideal for aligning the boards, so they come together cleanly, without a misalignment in the middle that would require resurfacing BOTH sides. That said, you could just as easily bolt both down, side by side, on the metal frame she’s using for a base, and it could work.

    Assuming, of course, that everything stays flat after the resaw…

    I met my wife while I was at North Bennet 7 years ago, I’ve danced this one a few times.

    It’s not so much about listening or being a decent guy. It’s her project. And, she may not have visions of creating an heirloom piece. She may just have visions of getting it finished without fussing too much, so she can put the books away. Does she want perfect, or done? This is all speculation on my part, but her vision of good enough may differ from yours. My wife knows I’m a perfectionist, and knows when to call me on it. Early on, I came off as too picky, and prone to getting lost in my own head. Not too impressive.

    Obviously, this is all speculative. Maybe she’s really fascinated by fine woodworking, and that’s the real point, in which case, go for it.

    If she’s not yet impressed, now may not be the time to show off the picky. Save it for an anniversary or birthday project. Most of the pains I take to impress my wife end up really being things I do to impress myself, based on MY understanding, and not on hers. It works, she knows when I’ve put that much attention into something. But the details… And the mistakes… that I see aren’t what catches her eye, because she’s looking through the eyes of a non-woodworker who’s really appreciative, and not through the layers of pickiness that I’m always trying focus through.

    Either way, good luck with both projects…

  2. abt

    Whatever happened to the good ‘ol spring joint? I’m pretty certain ‘The Schwarz’ has an article or two in back issues of Pop Wood that will guide the young padawan’s hand on the making of this superior joint. Try April 2009 for starters.

  3. Tom

    To get a live edge why don’t you split the board along the grain? A piece of rift sawn will give you a beveled natural edge, a quartersawn board will give a squarer (and possibly straighter) natural edge. Use a pair of metal straps for whatever reason, just slot three of the four holes on each strap with a rat tail file. This will allow for expansion. Extend the countersink chamfer along the elongated holes for a flathead screw. You can recess the plate to be flush with the underside of the shelf, but leave room for shrinkage, too. (Then tall books or ? won’t hang up on the strap…) [P.S. I think pmac stands for philosophical mentor and counselor ;-)]

  4. Recruiter

    Although not the same type of joinery, it give a bit of food for thought. If you look at a cross-section of how a bowling alley is built, they use 1×4 oak, layed on edge, with a small hollow on each bottom face, laid over a 4 ft angle iron to keep it flat. Then they glue and face nail each layer together They drill through the entire width, then use a threaded steel rod to pull it together. Then screw the angle iron to the underside. From there it is attached to the subdeck to keep it from moving.
    My point is, any method to keep the boards straight (no matter how crude), if it is the effect you want, will work.

      1. Recruiter

        The reason for my comment is simple. Edge glue, face glue, wide board, glue up, whatever. If it is the effect you are looking for, it will work, as long as you understand the mechanics behind it.

  5. kyvdh10

    I think you could use metal straps but you would have to account for the expansion as you’ve noted. Just screw the straps to the bottom of the two boards. The two screws closest to the joint should be done in the normal fashion with a pilot hole the same size as the screw. Any other screws farther away from the joint would need to have the hole in the strap slotted to allow for expansion. If you could fashion the straps to look rustic and medieval, it actually could look quite nice.

  6. trucker

    If you want perfect alignment as well as increased strength you could also use the festool domino system. That tool is absolutely outstanding and can really be a great timesaver. The floating tenons used are significantly stronger than biscuits and, since you are using 2 inch materials, would make super strong connections. Glue joints will also work if you do have access to the tool.

  7. sawdustdave

    “The Schwartz” tells us that hot hide glue w/o clamps can hold edge glued boards well enough to last for a long, long time. Personally, I have biscuits. Don’t use ‘em. Plane well the edges, glue, clamp. Done.

    The only thing biscuits do, in my experience, is make me purchase more biscuit and a cutter to use ‘em. I can save that money for a new hand tool or lumber.

    1. Chuck BenderChuck Bender

      Even hot hide glue (which I will heretofore only refer to as “hide glue”) benefits from being clamped. Clamped joints hold up better than rub joints.

      Biscuits make good eatin’. Not so good for joinery, however.

  8. mpoulin

    From experience, metal and wood have different coefficients of expansion so using metal strapping to join the two boards would likely result in splitting as the metal expanded at a different rate than the wood. If one were to leave a gap between the boards to allow for the differing wood movement, I suspect it would work fine. In the end, it depends on the look one were trying to create.

    If I were doing it, I would probably just use glue and no biscuits as modern glues seem to be stronger than the wood itself — but I have a Plano vertical press so alignment issues are not a problem. I would only use the biscuits to assure alignment.

    1. pmac

      (Since the woodworking portion of the post has been covered, let’s get into the relationship part of this post.) Ladies also love guys who listen. If she wants live edge, spend the extra money give it to her. If she wants straps, give them to her. If you don’t, and it’s not what she envisioned, she may say she’s happy with the piece, but down the road (if you’re still together) you will be having an argument/discussion about a completely unrelated topic and out of the blue will come,
      ” This is just like my shelf, you didn’t listen to me then and you’re doing the same thing now.”
      To which you will say “Where did that come from? I thought you liked the shelf and we discussed all the possible options.”
      She’ll say “You discussed, not me.”

      (All the married guys are laughing now.)

      She will always look at the shelf and if it isn’t what she had in mind you are screwed. She will forgive, but will never forget. So listen to the lass and give her exactly what she wants. She’ll be happy and you’ll be happy.

  9. Bill Lattanzio

    I think your best bet would be to plane the edges flat with your jointer plane (or a powered jointer if you have one) and just use glue and clamps. More than likely you will have to plane the joint flat no matter which method you use, as very rarely does a glue joint end up with a perfectly flat seam. But the glue alone should be more than strong enough to hold a long grain joint together without any other support such as strapping.

  10. sean3047

    My understanding is that biscuits and dowels don’t do much at all for the strength of the join, but instead are used as a means of aligning the boards to keep them flat.

    As for using metal strapping/braces, wood movement would definitely be an issue. In fact, being used to join a thick slab, I would expect it to not only result in cracking (or ripping out the screws), but I would guess the movement to be much greater problem on top (as it constrained so tightly below)..

    If the top is to be fixed to the metal frame below you’d need to allow for wood movement there as well.

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