![]() Titebond 2 has a spec of 3750 psi with wood failure rating of 72% per Titebonds website. In regards to strength this might resolve a bit of the speculation. Oddly enough, as I wrote this, I noticed Tom Iovino from Tom’s Workbench put up a similary-themed blog post in the community. ![]() If I were you, I would definitely opt for tongue and groove or mortise and tenon joints. But if the biscuits were used for end-grain joinery, I wouldn’t recommend moving that chest around too much. If the maker of that oak chest used biscuits in a bunch of long-grain joints, it would probably be a reasonably sturdy piece. But I do suppose for light-duty pieces, they would be acceptable. So in case you couldn’t already tell, I would never use biscuits as a primary form of joinery, especially when there are end-grain to long-grain joints involved. Make no mistake about it: the biscuit joint is no substitute for the mortise and tenon, or its little brother, Prince Tongue and Groove! All three of the biscuits weaknesses listed above are the reasons for this. As a result, the joint has a great deal of glue surface and strength. The real magic of the mortise and tenon joint is that it takes this end grain to long-grain union and converts it to long-grain to long-grain, simply by inserting one piece into the other. Traditionally, this is the territory of the King of Woodworking Joints: the mortise and tenon. ![]() So we absolutely need some form of reinforcement. Whenever end-grain is involved, the joint will be inherently weak using glue alone. Think of a rail meeting a stile or an apron joining a table leg. Now the second situation is end-grain to long-grain. But if they help you align the boards, I see no harm in using them. So adding a series of shallow biscuits isn’t really going to make the joint much stronger. As you have heard me and others say many times, the glue joint is stronger than the wood itself. In this long-grain situation, its really the glue that’s doing all the work. Some folks (including me) may use biscuits for alignment or “reinforcement”, but the truth is they do very little to strengthen the joint. Lets look at the two most common areas where you could use a biscuit, with respect to the grain direction of the adjoining pieces.įirst, there’s long-grain to long-grain (a tabletop glueup is a good example of this). But in most cases where biscuits are being used, its the glue that’s doing all the holding. And I honestly don’t think they are a bad option for light-duty pieces either. Ideally, the grain would run perpendicular to the joint.ĭespite their shortcomings, biscuits are still very handy for alignment, especially when doing big tabletop glueups. – The grain of the biscuits runs on a 45 degree angle. – The biscuit doesn’t penetrate very far into the joining workpieces: a #20 biscuit will penetrate less than 1/2″. – Biscuits slots can be a little tight or a little loose, depending on your machine and how steady your hand is. Biscuits don’t really have much to offer in the way of strength. Am I wrong? If I wanted to join two boards together, would a tongue and groove be more solid in the long run? What do you think? Anyway, I saw a video on youtube of this very nice oak chest, but the craftsman used mostly biscuits to join almost everything, I wouldn’t think that biscuits would be strong enough to last a lifetime. I don’t have many tools, and the ones I do have are Ryobi (fairly cheap) but I like them. Three sizes of biscuits are available and each come in 100 piece packs.I’m just getting started in woodworking. Biscuit joints are also easier to cut and align than dowels, so you'll spend less time sweating over how precisely you've marked your work pieces just before your glue up begins. Unlike a dowel, however, the biscuit's unique shape creates a much larger surface area, which serves to both increase the amount of edge grain that is anchored by the glue and spreads out the load from wood expansion and contraction over time. ![]() Like the time tested dowel, a biscuit's strength comes from its ability to absorb moisture from glue and expand within its slot, effectively locking the two joined pieces of wood in place from the inside. Corners, carcasses, and all manner of T-joints are all easily improved by using an appropriately sized biscuit. Laminated plywood sheets can be edge joined to make perfectly aligned paneling. Inherently weak miter joints can be trusted to hold without adding keys when you throw a biscuit inside. Puny though it may appear, the common beechwood biscuit can add a Herculean degree of strength to many end grain methods of joinery. The modern cabinet shop's best friend may very well be the squat little oblong wood chip we call the 'biscuit'. Fill Your Biscuit Tin And Make Some Joinery
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