Below Box Is An Andiroba Wood Embossed Gold Banded Jewelry Box. Dimensions Are 19 1/2" Wide x 11 1/4" Deep x 5 1/4" Tall. The Box & Lift Out Tray Bottoms Are Lined With Red Velvet. Middle Panal Has Ruby Red Cathedral Stained Glass Outside & Mirror Inside. Has 2 - 24 Karat Gold Plated Cup Pulls {Shell Design} For Handles & 2 - Large Polished Solid Brass 95 Degree Stop Hinges. Sold $2595.00

Exotic wood even in the raw is an investment. Once correctly worked and created into an object the investment will multiply many times in the years and decades to come. This is why it is essential to know and understand wood movement between the many different species of wood, in my opinion, the most crucial part of woodworking.

Trees can be classed or grouped in several ways. The lumber/timber industry uses two broad/generic classes or groups for the wood/timber that comes from trees, they are hardwood and softwood.

Hardwood comes from {Deciduous} angiosperms which are broadleaved and are either catkin bearing or flower bearing trees. Softwood comes from trees belonging to the order Coniferales/Coniferous gymnosperms which are cone bearing or evergreen and have needle or scale like leaves. There are exceptions! Some examples would be,

Balsa {Ochroma pyramidale} Janka Hardness 88 and Basswood {Tilia americana} Janka Hardness 410 are Deciduous and are extremely soft.

Cypress Black Australian {Callitris endlicheri} Janka Hardness 1460 and Yew Pacific {Taxus brevifolia} Janka Hardness 1600 are in the order Coniferales/Coniferous and are harder than Ashes {Fraxinus spp.}, Birches {Betula spp.}, Maples {Acer spp.}, Oaks {Quercus spp.} or Walnuts {Juglans spp.}.

The scientific difference is, in hardwoods the pores transport water through the trunk and branches to the leaves. In softwoods these pores are not present the water moves by way of fibrous like cells which conduct water.

As stated above softwood has no pores. Hardwood is either closed or open pored. Open pored means that if you look at it very closely it has fissures like lines.

Wood absorbs water from the air during high humidity causing it to expand, during low humidity the water evaporates from it contracting it. After a project is finished this process is called movement in service.

I place each species of wood into one of four wood movement categories {see below}, they are minute, small, average and great. The greatest amount of movement occurs across the grain {width.} Thickness has a lot less movement and the movement lengthwise is inconsequential. The thinner and more narrow the wood the less movement it will have. In fact wood that is less than 2 inches wide and 1/4 inch thick, the movement is minute or even inconsequential.

Coating the wood with a finish will not stop the movement it just slows it down! The finish you choose to use, will determine how long it will take to reach EMC. For instance wood coated with marine spar varnish will take a lot longer than wood coated with tung oil to reach EMC.

The process of reaching {EMC} equilibrium moisture content to be in balance with the surrounding air {not gaining or losing moisture} is a slow process that eventually brings the piece in balance with its surrounding environment.

There are a lot of variables that affect this process. Whether your house is air conditioned with refrigerated air or evaporative {swamp cooler} or a combination of both. If it is heated with gas, electric heat or a fireplace, how well insulated it is and how {tight} losing air to the outside by way of cracks around windows, doors and other openings. If you use a humidifier or dehumidifier system and how much direct sunlight a room receives will also impact the movement of the wood. Even keeping the door closed to a room that has a separate humidifier or dehumidifier will make a difference in the EMC of that room from the rest of house.

No matter where they are located in the world, 99% of structures that have a controlled indoor climate using some type of heating and cooling and do not use a humidifying or dehumidifying system, the EMC will be 6% - 14%. Structures with uncontrolled indoor climates, the EMC is usually not lower than 10% and can be high as 18% -20%.

Woods should be glued {laminated} whether edge to edge, face to face or edge to face only to other woods within the movement category they are in. Then if the piece is moved to a different environment the woods will expand and contract at approximately the same amount insuring that there will be no unnecessary stress and tension on the glue joint or either piece of wood, which could cause damage {cracks} to the weaker wood. The exception to this would be if using very small pieces of wood {narrow and thin}.

With cigar humidors for an example, they are normally lined with Spanish Cedar, which is in the minute wood movement category. When wood from one of the other movement categories is used for the box, the Spanish Cedar lining should be left floating or be slotted and stainless steel screws used to affix it. In this way the two woods can slide along one another resulting in no damage to the humidor when it expands and contracts.

When laminating different wood species together, try to keep the grain patterns on all the pieces somewhat uniform and not a contrast such as gluing a tight closed grained piece of wood to a loose wide grained piece of wood.

When several narrow pieces of wood are laminated edge to edge, look at the end grain and place them in an alternating grain pattern, hump up hump down. If you draw several circles inside one another, then draw a line down the center, the top half of the circle has the humps going up, and the bottom half going down. The end grain {growth ring pattern} will somewhat look like the circles cut in half.

Make sure that your wood is between 6% and 12% moisture content. Wood that is kiln dried to between 6% - 12% is extremely stable. If the wood is above 12% do not use the wood for your project until it has reached acceptable moisture content.

In this day and age owning a good moisture meter is essential to assure that the wood does not have an extreme change after your project has been assembled possibly ruining a future heirloom and costing you a lot of wasted time and money. The pinless type of moisture meters are best. From experience they are quite accurate. You do not have to worry about pin holes and sliding the meter on the face side of boards you can see the higher and lower moisture areas on the board, quite intriguing.

You should make a project {all parts} from one length of lumber, larger projects from wood that comes from the same bundle and same business. Even within a species, pieces of wood will vary in specific gravity {from different areas of the country or world} causing them to expand and contract at different rates.

Quartersawn lumber is more stable than Plain {Flat} Sawn or Rift Sawn lumber because it expands and contracts the greatest in thickness. To determine how a board is sawn, look at the end {butt} and at the growth rings. If the growth rings are 45 degrees - 90 degrees to the face it is Quartersawn, if the growth rings are 30 degrees - 60 degrees to the face it is Rift Sawn, if the growth rings are 45 degrees or less to the face it is Plain {Flat} Sawn.

When gluing wood together {especially oily exotics} you should blow the piece off with compressed air {100 PSI} first {safety note: be sure to wear a high quality respirator mask.} This works especially well with opened pored woods to get the dust out of the pores. Then make a sort of tack cloth by applying cleaner to a lint free cloth. Wipe the surfaces to be glued for better glue adhesion. I have found Acetone to be excellent for this, as it leaves no residue, does not raise the grain of the wood, evaporates rapidly and does no harm to the wood. I also use it in the same way, aforementioned above, before applying the first finish coat for better coating adhesion.

All glues have cons; it depends on what cons you want to live with. I have found polyurethane glues work exceptionally well especially on oily exotics. They are very flexible and expand and contract well with joints.

The below across the grain {width} wood movement measurements are the movement from 6% {EMC} equilibrium moisture content to 14% {EMC} equilibrium moisture content on a Plain {Flat} Sawn board 12" in width. If a board is 6" wide it will move one half the measurement and if you laminate boards together for a 36" width such as with a table top, it would triple.