The 3 cuts of timber: how best to use & specify them.
Quartersawn, riftsawn, plain sawn
These are essential terms to understand for a furniture designer and maker. They define the physical and aesthetic attributes of the material before any work has begun.
Interior designers, architects, specifiers and private clients (so everyone, basically) may not necessarily know the terms, but everyone will know what look they are aiming for with their wood, and a more detailed knowledge of how timber gets from the log to the table will help with an understanding of what is possible, and the best context for its use.
Put simply, quartersawn, plain sawn and rift sawn are the three main ways in which a log is cut into usable boards. Confusingly, different terms are freely used within the industry, but a look at how a log is converted will help clarify what the terms involve.
Plain sawn is the most common way a log is sawn, perhaps because it is the most inexpensive way to convert logs into timber. It also produces the most recognisable type of wood figure: the distinctive ‘cathedral arches’, so perhaps this also explains its prevalence.
Plain sawn oak, showing 'cathedral arches'
Looking at the end of a board of flat-sawn timber, you will see that the annual growth rings are around 30 degrees or less to the face of the board; this is often referred to as tangential grain, as the cuts are made on a tangent to the circumference of a log.
While it may be the most efficient means of conversion and produce the most familiar grain pattern, flat-sawn produces the least stable timber. This is because timber is hygroscopic: it expands and contracts with changes in seasonal humidity. But it is also anisotropic: it has different properties depending on the direction or orientation of the grain—it’s not the same in all directions—and one of the areas where this property is most clearly seen is in dimensional stability.
As a rule of thumb, movement across the tangential plane is twice that of the radial plane. So when this plane is the largest surface, as with flat sawn timber, the board will more susceptible to seasonal movement.
That was a bit technical, but suffice to say that flat-sawn solid timber is not to be used on wide, unsupported surfaces. Working with veneer avoids this problem, but that's a topic for another day.
Visually, flat-sawn timber is appropriate for when a stereotypical ‘wood’ look is desired. It also works well when a timber surface will flow around a corner, for example on a mitred cabinet. The distinct figure provides emphasis as it wraps around a corner.
Plain sawn zebrano veneer, with the grain wrapping around a mitred cabinet corner.
It is also the most suitable cut for some species. Walnut for example, is best employed when flat-sawn as it best displays the beautiful grain.
Plain sawn European walnut
As we can see from the diagram, quarter sawn material is cut from quarters of the log. This reveals a different face for the boards, giving straight grain, and the end of a board shows growth rings at 60-90 degrees to the face of the board.
When quartersawn, species such as oak will display spectacular figure know as ‘ray fleck’. This is the intersection of the tree’s medullary rays (which transmit sap within a tree) with the face of the board, and will be more prominent the closer the growth rings are to 90 degrees to the face of the board.
That got a bit technical again, so let's focus on the fun bit: how quarter sawn surfaces look.
Quarter sawn oak, beautiful rays dancing across the surface.
As well as oak, ray fleck is also seen in species such as sycamore, beech and London plane. Quarter sawn London plane is known as Lacewood due to its striking figure. I think it is just as beautiful as any exotic imported timber, and it grows right here in London. I source it from the streets and parks of our city, and a proud to promote it’s use as a high-value resource.
Lacewood, the with of the rays vary as the angle of intersection changes.
Quarter sawn material is more stable than flat-sawn, but is less efficient and therefore more expensive. It will give straight grain, which is desirable in many modern aesthetics, as well as producing spectacular ray fleck in particular species.
Quarter sawn material that shows ray fleck is a great way of introducing visual texture into a piece. It can also provide emphasis, and in the case of pronounced examples, a real focal point of a space.
Historically, quarter sawn oak was popular in the Arts & Crafts vernacular, gaining particular prominence in the work of Gustav Stickley. Interestingly, reproductions were often made using ash, which has a very similar grain pattern to oak, but lacks the rays. So although when stained ash is a convincing replacement, the absence of rays is an immediate sign the piece will not be genuine.
When clean, straight grain is desired with little or no ray fleck, rift sawn material is best. Quarter and rift sawn material are similar, but rift sawn is cut slightly off the true radial line, with the growth rings seen at 30-60 degrees to the face of the board. This reduces the angle at which the rays intersect the face of the board, giving a cleaner face.
Rift sawn timber is the least efficient and most expensive means of converting a log (as every board is cut on a radial line as the diagram shows) but it is the most stable.
Rift sawn timber is selected for its clean, sleek appearance, and I find it to be the perfect partner to more characterful timbers. It works particularly well with sleek, modern designs, and can provide unity and balance to a space that employs linear motifs.
Rift sawn oak, contrasting with the lacewood drawers.
Taken to its extreme you find man-made veneers such as Alpi products, which mimic straight grain species by stacking offcuts together and slicing through to produce clean, straight ‘grain’.I know a designer who, when faced with a particularly exacting client who wanted dead straight oak, offered a man-made product, describing it as Swiss oak. Very rare Swiss oak. Client and designer left happy.