Various Construction Methods for Custom Cabinetry

Within the realm of cabinet construction there are many ways to assemble a custom cabinet.  Having a thorough understanding of these various construction methods is crucial to the overall quality of the end product. AWI Standards section 400, has sketches of all the types of woodworking joinery.  When viewing these sketches keep in mind what you ultimately want for quality, appearance and function.  A study of this section will give you a very good idea of what you will need to specify. Refer to our Understanding AWI Cabinet Grades article for an overveiw of how of a particular construction method is directly related to the “grade” of cabinet that you specify and a link to section 400 of the AWI Standard book.

Following is a brief description of the construction methods most commonly used today by millwork shops.  The choice of construction method by a millwork manufacturer is greatly if not totally influenced by the equipment they have available.

Butt Construction Method

This is the least desired method of cabinet construction as it is essentially the most basic form of construction.  It does not have any type of reinforced joinery and is found in only the most basic of cabinet construction.  In the opinion of this engineer, shops that build this way are doing so to eliminate the cost of machining the parts and are offering the customer a “basic box cabinet”. This type of construction leads to product failure in a very short amount of time. Be sure that if you receive a custom cabinet quote that is exceptionally cheap, that the Butt construction method is not being used.

32 Millimeter Doweling Method

This construction method uses dowels to attach parts together.  This system is primarily used by a millwork shop that has CNC capabilities utilizing a CNC boring machine.  This type of machining can be a pod type or a platform type depending on the woodworking shops preferences.  Essentially the holes are bored into the face of the sides and then corresponding holes are drilled into the ends of the joining member, ie bottoms, backs, rails etc.  These pieces are then joined together using a small dowel, usually wood. 32 millimeter dowel construction is a sound method, however in my opinion not as good as rabbet and dado, which we cover in the latter of this article.

RTA Construction Method

This method is an offshoot of the 32 mm dowel construction, due to the fact that in most cases pre-drilling and boring needs to be done in precise locations. This system mainly uses mechanical hardware and fasteners and usually works quite well.  However one inherent problem is that the hardware is visible, usually on the inside of the cabinet. Another problem is the use of the less expensive hardware components, like plastic, that can break and therefore fail.  There are hundreds of styles of hardware applications to choose from when using the RTA construction method.

Spline and Wafer Method

This cabinet construction method is similar to the doweling method.  The difference is that it uses splines or wafers applied in slots in the face of the members and a corresponding slot in the ends of the joining members. Normally the spline is applied in a slotted dado that is continuous, where as the wafers are applied in 2” slots cut by a wafer cutter.  There are usually 3 to 5 wafers applied to each member dependent upon the size of the member and the joining member as well.  Spline and wafer construction is also a sound method, but it is labor intensive.

Rabbet and Dado Method

This is the most highly machined method of cabinet construction.  Actual rabbets and dados are machined into the parts which allow the joining members to fit within these slots and groves.  This is a superior method of construction due to the fact that once machined it allows for a larger glue surface during construction and thus constitutes the most strength and durability of all the construction methods.  When using the rabbet and dado construction method the joining member has a step over route on the front edge that allows it to “step over” the blind of the blind dado.

This article does not address every method of cabinet construction used nor every variation within these specific methods that millwork shops employ, such as ¼” backs, ½” backs, recessed bottoms, and or backs. However these are the basic and main cabinetry methods used in most woodworking shops and they are all  AWI recognized construction methods.

My next article, Ladder Base versus Integral Base, will discuss the different configurations to consider when using a particular cabinet construction method.