Know Your Butt From Your (Dove) Tail Joints! August 01 2013, 0 Comments
Not all wood furniture is created equally! I write this blog solely for you, the wood furniture end-user. There is nothing more disheartening than searching for and purchasing that “perfect” piece of furniture, only to have it fail on you shortly down the road! Why did this happen?? The answer is simple (and possibly painful to hear), but not all wood furnishings are made using tried, true and centuries old methods of wood joinery! If you want your wood furniture to last for years and generations to come, then this blog is one you will want to pay attention to.
Why are good wood joints important? Wood is anisotropic! All this scary word means is that wood has different strengths and weaknesses along the different planes of its structure. The longitudinal plane is strong when stressed (along the grain), but it is weak when stressed tangentially and radially (across the grain). Wood is also reactive to its environment. It expands and contracts as the air moisture content raises and lowers, but it does not do so equally across all of its planes! Therefore, it is up to the woodworker/designer to understand these inherent wood properties and use appropriate construction methods that address these issues. Probably the most important issue to understand is what joint to use when connecting two pieces of wood! What type of wood used is really not important if the furniture piece falls apart because of poor joinery!
Not Strong Structurally...
You have heard of the weakest link…well, the butt joint is just that! The butt joint is made simply by “butting” two boards together and using glue, nails, and screws to keep them in that position. (FYI, a structurally sound wood joint does not require assistance from other fasteners to do its job!)
This is basically a butt joint with help from wood dowels. Wooden dowels are secured into one board edge and then fit into holes drilled into the other board edge. It does provide a bit more strength to the joint and can be used to provide visual beauty when the dowels extend all the way through to the outside surface of the connecting edge.
Like the butt joint, the miter joint is not an inherently strong joint. It is a simple way to connect two pieces of wood at an angle. It requires additional joiners such as nails, screws or glue to maintain a connection. It is used as a method of transition when it is necessary to change board direction. A good example of this is the corner of a wood frame or when it is necessary to turn a corner with a baseboard.
Strong Structural Joints...
This joint method can be used to add strength and visual appeal to the butt joint. Basically the joint is achieved by inserting a strip of wood (spline) into grooves that have been cut into the two board edges being joined.
This method of joinery is quite strong and visually appealing. Two boards are joined by removing equal section portions from each so that when joined, they overlap one another.
Box or Finger Joint
As the name suggests, this joint is often used in box construction (i.e. jewelry boxes or chests). It has a decorative quality that can be enhanced with wood choice and/or finishing. This is a strong joint to use in corner connections.
Frame and Panel Joint
This is the primary joint used in cabinet door construction. Basically, each door is made up of two vertical members (stiles) that run the complete height of the door. There are also two horizontal members (rails) that extend the complete width of the door (minus the stile width) and then a center panel “floats” between these members. This construction method allows for the expansion and contraction of the panel due to environmental changes while not affecting the other member of the door.
Rabbet and Dado Joints
This joint is made by inserting or sliding one piece of wood into the groove of another piece of wood. The connection creates a strong bond between wood members.
The dovetail is an incredibly strong and visually appealing joint. The strength of the dovetail lies in the edges’ inability to pull away from each other after the connection is made. There are many variations of the dovetail, but due to its “dove tail” shape it is also an easy one to recognize.
Mortise and Tenon Joint
Like the dovetail – the mortise and tenon joint is clearly one of the strongest and most widely used methods of joinery in woodworking. It is simple, in that the connection is made by inserting the tenon from one board into the mortise of another. You will see this joint used in a variety of applications in the wood working industry.
So…now you are “in the know”!! Some of these joints may not be visible, but rather used purely for construction purposes. The advantage of a strong joint is that it can be exposed, if appropriate, and used to further enhance the detail and beauty of the piece.
Remember, in your travels and quest for quality pieces of wood furniture, be it custom, semi-custom, mass produced, reclaimed or newly claimed, you are now armed and ready with some powerful knowledge! The piece of wood furniture you want will be designed and produced by people who know how and why to use these construction methods, and more than happy to show you their craftsmanship (we love to strut our stuff!!!!).