This section is to provide a basic overview of the properties of wood products as they relate to cabinet and furniture construction.
Solid Wood
Probably the most important property of wood as it relates to cabinet and furniture construction is the way it expands and contracts with changes in atmospheric humidity. Some species expand and contract up to 1/8” per foot seasonally. However, they do not do so equally. As wood absorbs moisture it grows in width and thickness, but not in length.
(Illustration 1B01)
Wood Movement
This has limiting consequences for the conformation of solid wood construction. When two pieces of wood are joined so that the grain is at 90 degrees to each other, there is a conflict that can cause splitting in one of the pieces, or can cause glue failure or open joints. It is not a good idea to ask your cabinetmaker or designer to do this:
Left: dry environment, split on center panel
Right: moist environment breaks pieces apart
(Illustration 1B02)
On the left, the dry environment causes the wood in the center to shrink away from the two long sides, breaking them loose or causing a split.
On the right, the moist environment causes the wood in the center to expand, breaking the surrounding pieces apart. See the next section on Veneer, for the most common solution to these problems.
When solid wood pieces are joined crossing each other, it is a good structural practice to use joinery that allows expansion and contraction.
Left: Cutaway of inset panel with expansion clearance (the panel is not glued)
Right: Cutaway of end cleat with interlocked sliding joinery
(Illustration 1B03)
Other characteristics that any buyer or cabinet designer should consider include: appearance, strength (particularly hardness), workability (labor cost), cost, and availability.
Veneer and Veneering
Veneer is thin wood sliced from a log by a knife usually to a thickness of about 1/32”. Veneer of species that are intended for a visible finish surface are joined edge to edge and bonded to a core material.
(Illustration 1C01)
Left: crossed grains lock each other against expansion and contraction.
Right: random grain directions of fibers do the same.
(Illustration 1C02)
Illustration 1C02 shows the material layers of a veneered product.
The core material may be made of wood fibers or thicker veneers stacked across each other with the grain directions alternated. In both cases, the core material is structured so that it does not have significant movement with humidity, and solves the problem shown in Illustration 1B02 above.
To reduce wood movement (and outrageous cost) it is recommended that cabinet boxes be made of veneered sheet goods.
Joinery
Introduction
Wood joinery is the art of connecting wood pieces with consideration for the properties of wood described in Wood Properties, and other considerations mentioned in the sections below. This section is meant to make you conversant with the terminology as we develop your project. It is by no means a comprehensive list of all the variations and other joinery available.
Joinery
Butt Joint
This is the most basic joint available. Since the butt end of the joining piece does not penetrate, this joint is inherently weak, though it is suitable when the pieces are otherwise supported. It should be reinforced with screws, dowels, or at a minimum with nails.
(Illustration 2B01)
Biscuit Joint
This is a modern innovation created as a substitute for traditional mortise and tennon joinery, and a few other applications. It is not as strong as a mortise and tennon, but it is considerably less expensive. When the joining pieces are otherwise supported or when edge joining it is a good choice.
(Illustration 2B02)
Mortise and Tenon
The mortise and tennon joint is the strongest way to join two large pieces of wood in a T or L shaped joint.
(Illustration 2B03)
Cope and Stick
Used for doors and wall paneling. This is a traditional way of connecting the rails and stiles of a door, with or without additional dowels. It is strong because of the amount of glue surface, but dowels increase the longevity of the joint.
(Illustration 2B04)
Dovetail
This is a very strong and long lasting joint that is used primarily on drawers. Because of the interlocking design and large glue surface it is much stronger than any other type of drawer joinery.
(Illustration 2B05)
Miter Joint
This is a decorative joint similar to a butt joint. For doors it has to be reinforced by dowels for any useful life. Very large miters are not recommended because as the wood expands or contracts across the grain the miter angle changes and the joint opens and can even be broken. Wide miters outdoors are a particularly bad idea because of the extreme changes in humidity.
(Illustration 2B06)
Half Lap
This infrequently used joint is used mostly to overcome weakness when two small pieces are joined.
(Illustration 2B07)
Pocket Screw
Pocket screws are simply screws installed in a specially machined pocket so that they are below the surface of the piece being attached. They are convenient to use but have two serious liabilities; they do not provide a rigid joint so that surfaces that should remain flush shift, and the small amount of short grain capturing the screw is prone to breakage.
(Illustration 2B08)
Dado
This is simply a groove run down one piece to receive the other piece. It can be very strong.
(Illustration 2B09)
Rabbet
This is a recess run down the edge of one piece to receive the other piece.
(Illustration 2B10)
Cabinet styles
Frameless Cabinets
Frameless cabinets are just that- they are lacking a wood frame that covers the front of the cabinet boxes in face frame construction.
This is made possible with the use of euro hinges which are required for frameless cabinets.
Frameless Cabinets
(Illustration 3A)
Face Frame
Face frame cabinets use a wood frame to cover the front edges of the cabinet boxes. This is the traditional way of building cabinets. You can use either butt or euro hinges on face frame cabinets.
Face-frame Cabinets
(Illustration 3B)
Hardware
Introduction
This section is intended as a brief overview of some of the various hardware choices for cabinets. This only covers the basics- there are literally hundreds of possible hardware categories. Your cabinet shop and/or designer can and should apprise you of other hardware specific to your project.
Drawer Glides
There are two primary types of drawer glides available, side mount and under-mount. With under-mount glides the hardware is concealed underneath the drawer when you pull it open. Side mount glides are exposed on the side of the drawer. Under mount glides, especially soft self closing glides such as Blum Tandem are considered the premium choice. However, their load rating is not as high as that of many side mount glides, so most projects include a mixture, with heavy duty side mount glides for large drawers that will be heavily loaded, and under-mount for the rest. Self closing under-mount glides are expensive but they add a lot to the feel of a set of cabinets.
The following links are to sites that include glides:
Accuride's Slide Selector,
Blum Drawer Runner Systems
Hinges
There are two primary categories of hinges, concealed euro hinges, and butt hinges.
Euro hinges are constructed so that as they open they swing the door to the side, so that they can be mounted on the back of the door without causing binding. The range of swing depends on the particular hinge, from 90 degrees to 170 degrees. The wide swing hinges have a complex mechanism and are therefore bulky. Euro hinges do not need to have supporting members visible between the doors and are favored when an uncluttered appearance is desired. They come in
many forms for various applications. They do not have the longevity of butt hinges, and may need occasional adjustment. Euro hinges are economical.
(Illustration 4C01)
Butt hinges are what you see on a typical house door. The range of swing of butt hinges is 270 degrees, or until the door reaches an obstacle. There must be a supporting member showing at the hinge side of every door which almost always means they are used with face frames.They are not self closing and therefore require a catch. Since they are traditional visible elements there is a huge range of choice available in both finish and shape. They are favored for traditional designs. The cheapest butt hinges we have seen are about $10.00 a pair, and we have seen hand cast hinges costing $270.00 a pair. The labor for installation is also higher than euro hinges, as they are not adjustable and require a shallow mortise to be machined with precision.
Top view of butt hinges
(Illustration 4C02)
In addition to the main types of hinges there are other types available for special problem solving, including Soss hinges (similar to butt hinges but concealed in the side of the door without a visible pin-expensive), knife hinges that are minimally visible at the top and bottom, and piano hinges. See www.soss.com
Pocket Glides
Pocket glides are euro hinges mounted on a pair of glides designed to allow you to open a door 90 degrees, and then slide it into a pocket in the cabinet box. They are very useful for getting a door or pair of doors out of the way for open access to the interior. They are most often used to conceal a television.
One very common oversight in planning for pocket doors is that the expectation of how far they will retract is inaccurate. You need to subtract about 5” for the mechanism that rides behind the door and carries the hinges. This may be up to 2” more depending on the incremental size of the glides.
Proportions for a two door cabinet
(Illustration 4D01)
Proportions for a single door pocket door
(Illustration 4D02)
Practical considerations for designers and buyers
Introduction
Design/engineering is our own term for the melding of design with the practical realities of woodworking. Since we spend time on both sides of the fence we have become expert at reconciling the two. This section is here to provide engineering parameters to buyers and designers. Many parameters are not variables that can be adjusted to suit the design; they are instead requirements that, if not met, may force the approved design to change. It is hoped that this will be used by many to help mitigate that expensive phenomenon.
Building construction considerations
Number one on our list of building elements that adversely affect the cabinet process and finished product is surprise ductwork that is routed through the cabinets. We don’t understand why ductwork plans are either not made, or not vetted by the architect or builder to make sure there are no structural conflicts. We highly recommend doing so.
As I write this I have an engineer grappling with a critical audio video cabinet that has absolutely no place to put the equipment. The issue has him pinned down and is about to finish him off!
Early selection of the appliances and AV components helps the cabinet shop find any clearance conflicts that the dimensions of those components might reveal. We frequently find that, for example, an alcove is not planned deep enough to accommodate something like a wall oven, and this gives us a chance to advise a change in the building dimensions instead of having to compromise the cabinet design.
Hardware limitations
Drawer hardware
It is a good idea to check the overall height of your intended glides and to make sure shallow drawer sides will accommodate the glide height.
See interior clear height of drawers below to calculate drawer box heights.
Some of the less expensive glides only allow 3/4 extension, leaving ¼ of the drawer still inside the cabinet. If this is undesirable, check this.
Euro Hinges
If you are using euro hinges the absolute maximum thickness of a door is 1 3/8”. Above about 7/8 in thickness the angle of swing will be limited to something on the order of 95 degrees. See illustrations below for other limitations.
Normal maximum
(Illustration 5C01)
Thick door hinge with 3/4" thick door
(Illustration 5C02)
Thick door hinge with 1 3/8” thick door
(Illustration 5C03)
Touch latches
Most touch latches require a clearance of 1/8” behind the door. Making this decision late or passing it on late can cause whoever is doing the shop drawings to have to make multiple modifications to the dimensions throughout the room being changed.
Hinge and glide choices will be limited to those that are not self closing, or for which the self closing mechanism can be disabled (yes-Blum tandem glides work).
Locks
Just about any lock can be accommodated in cabinet engineering. However there can be unexpected cabinet changes required for many lock applications. Drawers are restricted as to the placement of the lock. If a lock is to be included it should be known by the person doing the shop drawings, and the conformation of the drawer front should be compared to the limits of the lock placement. In the case of gang locks for drawers, the drawers have to be engineered short of the back of the cabinet. It is a good idea to address this issue before the shop drawings are done.
Heavy duty pullout glides
(e.g. as used for pantry pullouts or televisions). Strength and rigidity require that heavy duty pullout glides be tall. If there are minimum height requirements for the pullout it is a good idea to spec the glide and find the height to assure sufficient remaining height. Fulturer has some excellent glides that move like magic even under a very heavy load. We recommend the 777 glide for large custom pantry pullouts.
Space Yields and Clearance Requirements
Interior clear yield of cabinets
Top view showing interior clear yield in a typical frameless cabinet
(Illustration 5D01)
Top view showing width loss in a typical face frame cabinet
(Illustration 5D02)
Interior height yield, and depth clearance requirements for a typical base cabinet
(Illustration 5D03)
Interior clear yield of drawers
You will lose approximately 3 ½” in width for frameless cabinets and 2” for face frame cabinets starting with the finish drawer front width.
Regarding the drawer depth, subtract 2 ½” from the overall cabinet depth and round down to the nearest 3” increment for Blum Tandem glides. For side mount glides subtract 1 3/4” and round down to the nearest 2”. If the cabinet is small enough for a ¼” back, that will increase the clearance by 3/4”.
Interior clear yield of drawers
(Illustration 5D04)
Drawer clear height yields
(Illustration 5D05)
File drawer minimums
Minimum heights for file drawers. It is possible, by changing the drawer bottom, to reduce the minimum drawer front heights up to 3/4”.
(Illustration 5D06)
Audio video
As of 2008 a cabinet that is to contain a receiver requires 21” clear interior depth. If esthetic considerations and the room dimensions allow a 24” overall depth then you can specify that depth and have no concerns. If not, provision must be made to let the cabinets into the back wall. If the cabinet is not going to contain a receiver (or the industry provides a shallower one that you can specify) you have more liberty. In that case, all of the AV components should be specified and the cabinet designed to yield the necessary clear depth. See interior clear yields of cabinets above.
With flat screen televisions the depth of the TV cabinet is no longer a ruling factor, if it is mounted on a fixed plate or swivel arm. If it is mounted on a pullout swivel the depth requirement can be prohibitive.
With a television it is important to allow for the space that any pocket doors will consume. See Pocket Doors below.
Appliances
The majority of large appliances require a full 24” of depth from the face of the cabinets to the back wall. Wall ovens often require more. Designing for 24 1/2” depth will allow for the shim space behind the cabinets to be shrunk to 0 during install if necessary, and still maintain the 24” clear depth (see Illustration 5D03 above).
One should also consider the counter overhang when placing adjacent door or window casings.
Pocket doors
Since pocket doors slide into a cabinet they cannot be used to cover the top and bottom of the cabinet box; panels above and below must cover instead. This is not possible when there is open space above or below the cabinet, and a trim piece will be required.
(Illustration 5E01)
Door overlay limits. This is the only possible way to achieve the absence of any trim piece between two separate cabinets with a pocket door next to the hinge side of a swing door. Both doors will swing only 90 degrees. If it possible to put the swing door hinge on the opposite side, this difficult detail can be avoided. With this arrangement the door thickness is limited to a maximum of 3/4”.
(Illustration 5E02)
With a pair of pocket doors you sacrifice 6” of the interior to the doors. If you do not include the 3/4” concealment panels then the loss is 4”.
(Illustration 5E03)
Geometry
Fillers at drawers
You must have fillers in inside corners where there are drawers to avoid conflict with the pulls.
(Illustration 5F01)
Fillers at walls
Fillers at walls. A filler is needed at the wall here for several reasons: The edge of the door needs to be perfectly straight and plum for the hinges to work, and it is nearly impossible to build the wall with adequate precision.
The door must open 90 degrees for the concealed drawers to pull out, and the door pull would interfere. Fillers allow for some small adjustment to fit the building. Buildings are not accurate.
(Illustration 5F02)
Fillers at ceilings
It is highly desirable to include a filler at the top of upper cabinets (left image). If it is not there the doors may hit a low spot in the ceiling when they open. There will be a filler behind the doors if they reach to the ceiling (right image) and the doors will be trimmed to fit on site. Buildings are not accurate.
(Illustration 5F03)
Edge treatments for panels
Post banded with veneer
Veneered material is cut to precise dimension accounting for banding thickness and reveal gaps then veneer is bonded to the edges. This method can use factory plywood or custom veneer. The face of the panel shows a very narrow border of veneer. This mostly disappears with the edge sanding. This is the most economical treatment for panel edging. It is slightly less durable than the other two banding methods.
(Illustration 5G01)
Post banded, solid stock
Veneered material is cut to dimension as above then solid wood is bonded to the edges. This method can use factory plywood or custom veneer. The face of the panel shows a border of solid wood. This method is in the middle of the price range. This is durable construction.
(Illustration 5G02)
Pre-banded
Panel cores are cut and banded before the face veneers are applied. This method can only be accomplished with custom veneering. The face of the panel shows no edge detail at all. Custom veneering is quite expensive. The expense is further increased by the fact that the shop will be veneering multiple individual panels, and the veneer must line up across panels. This is very durable construction.
(Illustration 5G03)
Veneer
Intro
(Illustration 5H01)
Veneer is thin wood that is bonded to a stable core. Many species are available that are not available as solid wood, extending the pallet of available woods for your project. Please be aware that, since sold wood is not always available (or may not match) that your veneer choice may compel a different species for any molded trim.
Square trim can usually be accomplished with veneer. One should also consider available lengths when specifying a veneer for a project. Check out this site to cruise through a lot of veneers: Veneer Online.
Types of veneer cuts
The look of a veneer depends in part on the type of cut that is used to produce it. See below.
Quarter sliced
Quarter sliced veneer has narrow grain lines that tend to run parallel to the sides of the leaf. In oak it produces a figured pattern of flakes.
(Illustration 5H02a)
Plain sliced
Plain sliced veneer has broad grain patterns, often with cathedral shapes.
(Illustration 5H02b)
Rift sliced
Rift sliced veneer has narrow straight grain like quarter sliced veneer, but the angle of cut is such that it lacks the figure that often appears with quarter slicing.
(Illustration 5H02c)
Rotary cut
Rotary cut veneer has very broad (sometimes repeating) and somewhat random looking curved grain patterns.
(Illustration 5H02d)
Veneer Layouts
There are lots of patterns for bonding adjacent veneers to a substrate. See below.
Slip match
Slip match keeps all the veneers oriented the same way with all the same faces exposed.
(Illustration 5H03a)
Book match
With book matching every other leaf is flipped over so that a pattern of pairs of mirrored leaves is produced.
(Illustration 5H03b)
Random match
Veneer pieces are placed in no particular order, usually with varied widths. This has the look of a lumber glue-up.
(Illustration 5H03c)
Running match
This applies to the way the veneers run across adjacent panels. Slip, book, or random match can all be laid up in a running match. Veneers are run across the panels without regard for the breaks between panels, so that the cutoff from one panel becomes the first piece of the next panel.
(Illustration 5H03d)
Balance match
Slip, book, or random match can all be laid up in a balance match. Veneers are equal width for each panel and may be odd or even in number.
(Illustration 5H03e)
Balance and center match
Balance and Center Match. Slip, book, or random match can all be laid up in a balance and center match. Veneers are equal width for each panel and are always even in number.
