Selecting & Using
Green Wood
Charlie Self
By
© 2005-2006
Charlie Self

               Hardwood grading is a mystery to many people, and, it sometimes seems, a mystery to some of the people
    producing and selling the wood, as quality applied to a particular grade can vary greatly from one supplier to another.
                Generally, the following grades are relatively easy to find in most domestic lumberyards:
    Firsts and Seconds (FAS) is the best and most expensive grade of domestic hardwood. When boards  are 6" and
    wider, 8' and longer the yield must be 83-1/3% clear face cuttings with minimum sizes of 4" x 5', or 3" x 7'. Suitable for
    any projects where clear, wide boards are needed.
                Selects is lower in quality, because of its slightly lower yield. The face side is FAS with the back side No. 1
    Common. When boards are 4" and wider , 6' and longer, the effective yield is 83-1/3% clear face cuttings with minimum
    sizes of 4" x 5', or 3" x 7'.  Where it an be readily found, this is a great substitute for FAS for most projects, because on
    most projects only a single side shows.
                No. 1 Common is thrift or shop grade. Boards are 3" and wider, 4' and longer, giving 66-2/3% clear face
    cuttings with minimum sizes of 4" x 2', or 3" x 3'. For any project where length and width are less important, this can be
    a major money saver.
                No. 2A & 2B Common are  useful only on small projects, because of a 50% yield of
    clear face cuttings, with minimum board size at 3" by 2'. Great for makers of small boxes that are lined, but not of much
    use to the average woodworker.
                There are other, lower grades, but their usefulness to the woodworker is so limited as to make description
    unnecessary. We need to understand, too, that individual retailers and sawmills will put their own interpretations on
    any of these grades.


    1.  A board foot equals 144 cubic inches. Take the width and thickness of a board in inches, and multiply by the length
    in feet.  Divide the result of that by 12, and you've got the number of board feet.  In other words, a 2" x 6" x 12' board
    has 12 board feet. Because rough lumber is sold by the board foot, it pays to get a solid grip on figuring board feet for
    different width and thickness lumber.  
    2.  Rough cut lumber is measured in quarter-inch steps, or quarters.  Thus, a one inch thick board is 4/4, while a three
    inch thick board is 12/4.  Commonly, rough cut lumber is available in 4/4, 5/4, 6/4 and 8/4 without special orders.  If a
    particular wood is in demand in 16/4 thickness, it can usually be ordered. Loss to planning is about 3/16", so the
    thickest planed boards available from 4/4 lumber are usually about 13/16".  Buy lumber thick.  If you are sure you need
    1" thick finished material, don't by 4/4.  Try to locate 5/5 or preferably 6/4.
    3.  Don't expect to get full length clear cuts from lumber.  Most of the time, boards will have checks, knots and possibly
    some wild grain, and maybe some end splits that have to be removed.  That means you need to allow 20% in length
    for such losses.  For an 8' project, expect to buy boards that are at least 10' long.
    4.  Once that roughness is planed off, charges increase, but you are still paying for rough lumber sizing:  for example,
    depending on outlet, if you buy S4S hardwood that is 13/16" thick, you're going to pay for board feet as if you bought
    full 4/4 (which you did, because the lost 3/16" is what is planed off).



    1. Always check for cup. Cupping is bending across the width of the board's face--view it on end and see the ends
    pointing up (or down if you've got the convex center up).  Jointing the concave side removes cup, but reduces the
    possible finished thickness of the wood.  The only way to remove cup in some boards is to rip it up the center and then
    to joint each piece separately.  Don't use a table saw to rip such boards because the chances of kickback are raised
    by a huge percentage.  Use a bandsaw, or a circular saw and guide, to do the ripping.
    2.  Look for bow in the wood before loading.  A bowed board shows bend across its width. Jointing with the bowed side
    down eliminates mild bow, again reducing final board thickness appreciably. Avoid the temptation to force the board
    down flat on the knives as it is jointed.  Severe bow forces you to cut the board into shorter lengths before use, after
    which they'll still need jointing to remove the bow.
    3.  Crook is bending along the length of a board.  Getting rid of crook narrows the board.  Crook is removed by jointing
    or ripping (you'll need a sled or a carrier board to rip such a board and get a straight edge).  If the crook is minor,
    losses in board width may be minimal.  If crook is severe, the board may have to be crosscut into shorter, mildly
    straighter pieces before it is ripped or jointed.
    4.  Twist can be described as a high corner in a board. No matter how you place it on a flat surface, at least one
    corner is in the air when the others are flat. Boards that have twist are best left on the pile for others to deal with.
    Flattening is difficult, and twist is apt to return with changes in season. If a board with twist has to be used, cut it as
    short as possible before flattening.
    5.  Look for oval patterns. Usually involving knots (but not always), oval swirls in grain indicate probable planing
    difficulty because the change in grain pattern increases the chances of major tear-out. Ovals can be cut out, reducing
    board size, or hand planed from both directions.  Some oval patterns are visible at the board edge more easily than in
    the middle. Ovals may also produce a fairly spectacular grain pattern, useful in some projects.



                Check board color. Whether lumber is being bought for a project or for resale, keeping color as consistent as
    possible throughout the stack is a good idea.  Make comparisons in natural light if at all possible, and either leave
    behind off-color boards, or separate them out for other uses.
                Check board edges. Curly and birds-eye figures often show up more easily in board edges, so if you're looking
    for fancy figures for a project, check board edges. Obviously, this is difficult in rough cut lumber, but it is possible,
    especially with curly figure that may be very obviously darker and lighter within a few inches. Too, some mills will plane
    an edge for you, at low cost, so you can check.  Others will let you use a small plane of your own to check out sides.
                Selecting planed wood is reasonably simple, because you can see almost exactly what you're getting, and
    measure the exact size of the finished product.  Selecting project wood from stacks of unplaned wood is more difficult,
    but rewards the selector well if a few facts are kept in mind.


    Bow: Distortion of a board along its length. A bowed board  is not flat lengthwise.
    Check: A crack in the surface of that doesn't go all the way through the board. Results from uneven drying, in direct
    sun or from too aggressive a kiln drying schedule.
    Crook: A deviation in end-to-end straightness, from distortion across the board's width.
    Cup: Distortion of a board across its width, such that board sides
    (horizontally) rise up and the center is convex on that side.








    Knot: Parts of branches the tree has overgrown. Black knots are dead wood, from dead branches, and may be loose
    or tight. Encased knots are those which will only fall out of a board when under direct pressure.  Pin knots are less
    than an eighth inch in diameter.  A spike knot has been cut along is axis giving it a stretched, spike, appearance.
    Mineral Streak: Discoloration of hardwoods that may range from
    olive green to brown to black depending on wood species and mineral.
    Pith: A portion of wood often softer than the
    surrounding board. More often found in
    heartwood at the tree center. Pith that is as
    hard as the surrounding board is not a defect.
    Sapwood: The living portion of the tree from
    the heartwood to the bark. Sapwood tends to
    be more pale than heartwood in most species,
    so is sometimes considered a defect.
    Shake: Separation along the grain usually found between rings of annual growth.
    Stain: Discoloration in a board, such as blue stain caused by fungi. Usually on the board surface: other colors may
    range from pink to gray to brown.
    Wane: The result of a board being cut too close to the outside
    of a tree.  It may include bark, or the bark may have
    dropped off.
    Warp: A term for variation in the flatness of a board. It may
    include bow, crook, cup and/or twist.


                Start by figuring your board foot needs with reasonable
    accuracy--if you're going to err, err on the side of too much.  Begin
    selecting with an aim to getting a stack or stand or selection at least
    double the board feet the project needs.
                Now, sort for the flattest, straightest best looking boards, setting them aside or keeping them in sight.  This is
    the spot to select about double the number of board feet you believe you need, or a bit more.
                Go through your first selection and set aside any boards with visible sapwood.
                Sort very carefully for knots, stains, checks, wane, or other major defects, including surface chip out from
    planing.   For rough lumber, you may or may not be able to see many major defects.  The best defense there is to
    select another 10 or 15% extra.
                Compare boards to select the best color match.  Leave this step out when buying rough lumber, except for the
    very roughest matches.
                Finally, sort the stack for the boards with the straightest grain.  If you're looking for birds-eye, curly or other
    strong figure, omit this step.
                After making your final selections, add up the board footage (thickness x width x length -- all in inches -- and
    divide by 144) to make sure you have enough lumber.  It's often possible to pull the original double-what's-need pile
    down to less than what is really needed.  If that happens, select some more boards and start again.


        
                When shopping for hardwood lumber, there are some other checks or ideas that are a big help. Look for mills
    that do hit and miss surfacing, instead of leaving all their material rough cut. This kind of planing just skims the board's
    surface, but opens up a look at the patterns in boards that is much easier understand than is finding good figure in
    rough cut lumber. There is a corresponding reduction in board thickness, say 1/32", but you lose that anyway later
    on.  Just don't get upset when you get charged for 8/4 and the real measurement is a shade less  H-M planing is an
    inspection tool, not a finishing process, so don't expect superb surfacing. It makes your check of a board's figure and
    color a great deal easier, at almost no cost.
                If you have the shop equipment (a bandsaw with at least 1 horsepower, and a 3 or 4 tooth per inch blade), buy
    thick. Thicker wood can be easily resawed and planed into thinner, and gives the option of matching pieces on doors
    and other wider panels that have to be glued up. Simply resaw that 8/4 material into two 3/4" pieces of stock,
    bookmatch and glue up. If you need two 1/2" thick pieces, resawing 6/4 makes more sense than does planing down
    two pieces of 4/4.


                If you only have a small planer, or no jointer, consider some options that may be available at low cost at your
    sawmill. A straight line edge gives you a single edge that is straight, and is probably the lowest cost such service
    around. S2S is surfaced, two sides, which means both sides are planed. S2S can be exceptionally handy for those with
    portable planers, or with no planers. S4S means all four edges are surfaced, and the board is, or should be, ready for
    use. Costs and set up fees bounce all over the place, and you have to be the ultimate judge on whether or not it is
    worth the money. For modest amounts of lumber--say less than 100 board feet--the cost per board foot for the milling
    may be supplemented by a set-up fee in some mills. Such services can get lumber right down to the size needed for a
    project, with cuts to length and shaping of joints and decorative parts being all the work you need to do.  It also adds
    considerably to the cost of rough cut lumber. For those with a small portable planer, the concept of a straight line edge
    and S2S has to be attractive, but a straight line edge by itself, at a mill that already skip (hit and miss) planes their
    woods,  is enough to save lots of work.  Usually,  S2S is cheap enough to be a good bet for most woodworkers.  
    Jointing one edge, unless the boards are over 8' long, is not all that hard or time consuming, but getting it done at the
    mill can save much time.
                Once the lumber is bought, paid for and transported, careful storage is imperative, unless you're buying just
    enough for a single small project. With larger amounts, dry storage indoors is best, with stickers still used between
    boards, at 24" intervals (stickers are not classed as an essential at this point, but without them, you must make sure
    the stack is dead level, and all boards supported along their entire lengths).



                One way to save a lot of money is to buy green lumber and do most of the seasoning yourself, in a process
    known as "air drying."  Doing this properly is a bit of a challenge: some woods are far easier to dry without major
    losses than are other, but correct procedures ensure that you'll get the maximum yield from your purchase of green
    wood.  Select for appearance as already covered, and avoid boards that are  cupped, or warped in any way. You will
    be air drying this material for at least 12 months, so any problems currently present will be magnified as time passes.  
    Second, store the lumber correctly.  A good base that is level is not just helpful, it is essential.  You can use cement
    blocks as the actual base, raising the bottom of the stack off the ground to allow for air flow.  On that, place landscape
    timbers or a similar dry wood (almost dry in the case of most landscape timbers). I make my stacks 4' wide (half the
    length of a landscape timber, so the timbers are cut in half for use in my stacks).  Start by laying a single timber along
    each row of cement blocks: cement block rows should be placed about 18" apart. Put a 4' landscape timber across the
    first timbers. This gives an overall height off the ground of more than 10", more than enough to allow plenty of air flow.
                Place the first row of boards, moving them close together, but making sure there is a 1/2" gap between boards
    (again, air flow is needed).
                Lay stickers every 20" to 24" on the row of boards (at a 90 degree angle to the boards). Lay your next row of
    boards, keeping the 1/2" spacing (but that doesn't have to be directly over the lower row's gap). Continue stacking and
    stickering until you've run out of wood or the stack is getting too high for safety (4' is about as high as I care to go, and
    if the wood is really rough, with a lot of misshapen or off-size pieces, about 3').  Stickers should be placed
    approximately one above the other all the way up the stack.
                Cover the top.  Do not cover the sides. The best material for covering the top is aluminum, or galvanized, sheet
    roofing, placed so that it overhangs ends and edges by no more than 3".  Weight the top with cement blocks or other
    heavy materials to help keep the boards flat.
                Walk away.  
                Keep a periodic check on the stack to make sure it isn't shifting, or the cover hasn't blown off.  Otherwise,
    hands off for 10 months or more.
                When 10 months have gone by, buy or borrow a moisture meter and check the moisture content of the wood.  
    It may range down from 15% to as low as 8%, depending on your location. The higher figure is the most likely. Move it
    indoors now, so that it can continue drying. If you're in a very humid area, you may want to find a local kiln to finish
    drying your lumber (and, of course, if you need it in a rush, you need to find a commercial kiln).
                Figure on a material loss of 50% when home brewing hardwoods.  If you're lucky, you might get a 60% yield,
    but 50% is more probable.  
                You're working for the money you save, but many woodworkers feel better about wood they cook themselves,
    and believe, usually rightly, that they can actually afford much more wood by seasoning it themselves.


        
Measuring Wood
Inspect for Quality
Other Checks
Defects To Watch
Step Your Way To Good Lumber
Points To A Good Purchase
Options At The Sawmill
Buying & Drying Green Lumber
Bad cup in red oak.
Red oak with a
knothole and
sap streaks.
Don't mistake
cherry's pitch
pockets for
mineral streaks.
Pitch pockets
do not affect
grade.
End splits and other faults may be
common with green wood that is not
carefully dried.
Wany board shows spalting, too.
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