Understanding Industry Grading, Cuts and Measurements
No matter how long we've been working with
wood, the material still manages to surprise us every now and then.
Wood is unusual in that most of the surprises are quite pleasant. There's
nothing like the feeling of applying a first coat of sealer or finish
and watching a project literally come to life right before your eyes.
While that reward comes at the end of the construction process, it is
in large part due to decisions you made before a single cut was made.
I'm talking, of course, of the buying process.
The easiest way to examine
that process is to separate the individual decisions that need to be
made. These include:
1. Choosing a Species
2. Choosing a Cut
3. Choosing a Grade
4. Choosing how much lumber to buy, and in what
5. Choosing a Supplier
Links to Relevant Hardwood Sites
1. Choosing a
Hardwoods are deciduous (non-evergreen) trees which produce broad leaves,
a fruit or a nut, and in most cases go dormant in the winter. The term
"hardwood" isn't literal: some species of softwood, like old
growth fir, are pretty dense, while some of the trees classified as
hardwoods (like aspen) are really quite soft. The factors which control
our choice of species are aesthetic concerns (color and grain patterns),
durability, and workability. While the aesthetic factors are essentially
subjective (everybody has to make their own call), durability and workability
are far more predictable. They can both be measured, as both depend
quite a bit on density and hardness.
The hardest domestic species, according to the USDA, are (in order,
hardest first) hickory, pecan, hard maple, white oak, beech, red oak,
yellow birch, green ash, black walnut, soft maple, cherry, hackberry,
gum, elm, sycamore, alder, yellow poplar, cottonwood, basswood and aspen.
Many imports such as rosewoods and ebony are at the top of the hardness
scale, while mahogany, sapele, makore and other popular architectural
millwork species are somewhere between the middle and the lower end
of the scale. Hardness doesn't necessarily mean hardship: just because
a species is hard, it isn't always hard to work. For example, I'd much
rather work any of the oaks than gum or cottonwood. Oak is predictable
Density and hardness can be challenging to grasp.I personally like simple definitions, such
as "Wood density is weight per cubic foot." That gem originally came
from the Wieland
& Sons Lumber Co. site, which went on to say that "density
is a way of determining the ease of working a specific species of wood.
Dense woods are harder to work with and fasten together, but once fastened
they hold much better than less dense types of wood." The Wieland
site includes a table (below), which lists the densities of various
domestic hardwoods. The numbers are all approximate and "should
only be used for relative comparisons among each other". What's
interesting is that the density certainly has a strong relationship
to the hardness of the stock (basswood goes through the table saw with
a lot less effort than hickory), but I'm not so sure that I totally
agree with the statement that density is a way of determining the ease
of working a specific species of wood. For example, butternut is relatively
soft (lower density), yet it can be a pain to sand and finish. That's
because it is, in the words of my pre-teen son, " kind of furry".
One other point worth noting is that pine, a softwood, can actually
have a higher density than basswood, which is categorized as a hardwood.
(The USDA list is in a slightly different order, which probably reflects
the subjective nature of wood.)
Grain Pattern and Defects
Grain pattern is important, and is an indication of how well a piece
of wood will work, and how stable it will be over the years. Straight
grains (such as those found in quartersawn stock: see below) present
a workpiece which will in general move less and hold more: it will be
stronger than stock with wavy or spiral grain, although it might not
be nearly as interesting aesthetically. Irregular grains such as fiddleback
or bird's-eye are beautiful to look at, and rather difficult to work.
The key is perhaps to progress from straight grain to figured stock
at the same rate that your woodworking skills evolve.
Some species are prized for their natural defects (such as burls, insect
damage, water damage and so on). But nobody buys lumber for its manmade
defects. These are generally related to the drying process.
More Information on Specific Species
For more information on a specific species, there are a number of apps on the market. One can also visit The American Hardwood Information Center and at the top of the page click on 'Species Guide'. Another
wonderful resource is no longer in print, but is well worth searching for online. It's Ernest
Scott's beautifully produced book, The Illustrated Encyclopedia
of Working In Wood (ISBN 185152875X 9781851528752). The glossary defines hardwood as "a botanical term used for broad-leafed
trees. The wood is not necessarily hard."
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2. Choosing a Cut
There are essentially three ways to saw a log and each one produces
a very different kind of board. The three methods are Plain sawn, Quartersawn
and Rift Cut.
Plain sawn stock (on the left, below) is by far the most economical
and, therefore, the most common cut. This produces the familiar cathedral
grain found in standard #2 softwood boards at a lumberyard. It involves
the least amount of waste and the most lumber from each log.
Quartersawn hardwood (center in the illustration below) is produced
when the log is cut radially at a 90-degree angle to the growth rings.
This produces boards with very straight, tight grain and it's absolutely
ideal for furniture building. Gustav Stickley, perhaps the greatest
woodworker America has ever seen, used quartersawn white oak almost
exclusively for his Mission and Arts & Crafts furniture. The cut
is not very economical, so the price of the stock is considerably higher.
Rays or flake, which show up as golden ribbons crossing the grain in
oak, are a prized attribute of quartersawn lumber.
Rift cuts (at right in the illustration) are a variation on quartersawing,
where the cut is made at a 30-degree or greater angle to the direction
of the growth rings. This produces a very clean, uniform grain pattern
which is ideal when boards are to be edge-glued to make panels: the
joints are almost invisible. This cut is rare and quite pricey, and
is used in top-end architectural millwork shops - the kinds of shops
that produce fancy desks and paneling for the boardrooms of the Fortune
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3. Choosing a Grade
When ordering hardwood either over the Internet or over the counter
at your local lumberyard, the National
Hardwood Lumber Association guidelines for hardwood grading (below)
are a great place to start. But they are not the only consideration.
By its nature, wood is not all identical. The Association's rules get
you close, but you'll still need to add some specs of your own when
placing orders. For example, if you just ask for FAS cherry, you will
get a mix of heart and sapwood in random widths. If you need all heart
in 7" boards, you need to tell your salesperson.
The following grades cover almost every hardwood board that is suitable
for hobbyists who turn on the lathe or build furniture. They are...
||Firsts & Seconds - the clearest grade, 10/12ths
of each side of every board is clear.
FAS is generally used for large clear parts such as moldings,
tabletops, solid wood doors etc.
||Firsts & Seconds on one face - 10/12ths of each
board is clear on one side.
It may have minor defects on the other.
||No. 1 Common is 8/12ths clear and is a cabinet grade
More than 50% of #1 hardwoods end up in kitchen cabinets.
No. 2A Common is 6/12 clear and most of it ends up as flooring.
No. 2B - 6/12 sound wood, it is essentially used in upholstered
The NHLA site is worth a visit (just click on their
name in the hyperlink above). They have a very comprehensive array
of publications covering a multitude of hardwood topics, and their
prices seem quite reasonable.
For those of you selling hardwoods or
hardwood products professionally, or for serious amateurs who want
to know more, there's a very detailed analysis of industry standards
available on the Web. It covers everything from humidity to defects.
You can download this information as a PDF file from the Architectural
Millwork Institute, a most reputable and impressive organization.
The file is an extract from their manual "Architectural Woodwork
Quality Standards Illustrated", which they sell for $10.00 to
members and $100.00 to non-members. The book can be ordered online
or by phone: (301) 953-7264. (Woodezine has no connection
with the Institute. We just admire what they do.)
If you haven't downloaded a PDF document before, you might need to
go to the Adobe
site to put Acrobat Reader on your computer. And I should
mention that it will look like nothing is happening for several minutes
while the AWI file downloads. Just hang in there.
Finally, a word about kiln and air drying.
We had intended including information on this subject in this feature,
but we gathered so much information that we've decided to do a complete
article on it in the March issue instead. For now, let's just say
that we prefer kilns to air drying, and we always ask our supplier
to deliver kiln-dried lumber. I'm sure some of you disagree.
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4. Choosing how
much lumber to buy, and in what dimensions
Hardwoods are sold by the board foot, which is 144 cubic
inches (for example, 1" x 12" x 12" or perhaps 2"
x 6" x 12") in its rough state. Generally speaking, the thicker
or longer the board is, the higher the price it will command per board
foot. Species, cut and grade all factor into the price. The most common
thicknesses for hardwood are 4/4 (called "four quarter"),
which is 1" thick in its rough state; 5/4 (1-1/4" thick),
6/4 (1-1/2" thick) and 8/4 (2" thick). A myriad other thickness
are available, especially if you buy a log and have it milled to your
If you have access to a thickness planer and a substantial band saw
which is capable of resawing wide boards, your best bet is to buy the
thickest stock you can. This is especially true for turners who are
going to face-glue boards to create large turning blanks, or furniture
builders who make laminated curved pieces. If you're building fairly
conventional projects, you may want to save a few dollars and stick
with 4/4 stock.
While most yards sell hardwood lumber unplaned (rough), some companies
sell only S2S stock. This is planed on two faces, but the edges are
not straight. You can usually have the company rip one edge straight.
Planed stock usually comes in at 13/16" thick, which is wonderful
if you're edge-gluing boards and want to plane them to 3/4" after
the glue cures.
The most expensive way to buy hardwood is planed on all four sides,
and it's probably not as useful either. The boards have been ripped
to a uniform width, so the mill may have taken 1/16" off at one
end of the board, but maybe and inch or two off the other end.
When you bring lumber home, let
it sit for a few weeks if possible, to acclimate to the ambient humidity
in your shop. This will reduce the amount of movement after your project
has been assembled.
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6. Choosing a
There's no question that nothing beats a hands-on visit to the hardwood
supplier, where you can examine each and every board at your leisure
and pick the cream of the crop. However, that's not really a possibility
for millions of woodworkers who live outside major cities (myself included!).
The next best option is to hook up with the biggest cabinet shop in
town and talk them into letting you raid their stash every now and then.
Other options include hooking up the trailer, loading a couple of
buddies from the local guild, and then driving half
a day to the nearest mill to buy air-dried stock which you can share.
If you live anywhere along the east slope of the Rockies, call Rattlesnake Woods in Cheyenne, Wyoming at 307-214-4328. Shipping costs
can be quite reasonable from online suppliers too: here are a few to get you started...
|L.L. Johnson Lumber Mfg.
||San Leandro, California
|World Timber Corp,
||Hubert, North Carolina
|Steve Wall Lumber Co.
||Mayodan, North Carolina
||St. Louis, Missouri
|Goby Walnut Products
|Exotic Woods Co., Inc.
||Sicklerville, New Jersey
||Chichester, New Hampshire
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For more information
on hardwoods, visit these excellent Web sites...
Millwork Institute (AWI)
& Sons Lumber Co
International Forest Products
Hardwood Lumber Association