Characteristics of Woodand

Squaring stock

Characteristics of Wood• Trees provide us with: · lumber

• plywood• Paper• medical supplies and drugs

• All trees are classified as either · hardwood

• softwood • Deciduous trees (hardwoods) - shed their leaves at the end

of the growing season Ex. Oak, maple, cherry, ash

• Conifer trees (softwoods) - have needles and cones

Ex. Pine, spruce, fir, cedar • All types of wood vary in color, strength, mass and grain pattern.

Parts of a TreeCrown - Includes the leaves and the branches - Creates oxygen and food (sugar) by

photosynthesis

Trunk - provides support for the tree - transport nutrients and water from the roots to the crown - moves the food made by the leaves back down to all the branches and the rest of the tree

Roots - gathers water and minerals from the soil

Structures of Wood

Pith

/Sapwood

Pith

= 1 year of growth

Cutting and Milling Lumber1. Logs are cut into rough boards of various thickness, with the use of bandsaws or

circular saw (depends on the facility and the price of the wood) 2. Edgers (cut width) and trimmer saws (cut length) cut boards to proper widths and

lengths. 3. All the boards are then sorted, graded and dried. 4. Drying Lumber - green lumber is 50% water dried lumber is 7-10% water

5. Grading - the grade of the lumber depends on the amount of defects in the wood

- In general, defects decrease the value of wood although some people like specific defects in wood and will pay extra money for it!ex. Wormy butternut or Birdseye maple

Types of Warping in Lumber• As wood/lumber dries weird things happen!

BOW

CUP

TWIST

CROOK

Natural Defects in Wood

Pitch Pocket

Wane (bark)

Stains and wood rot

Worm/insect holes

Pith

Types of Wood Knots

Dead Knot -will fall out Live or Tight Knot – will not fall out but may chip

StockThickness- measures the distance between the

sides Width - measures the distance between the

edges Length - measures the distance between the

ends - usually is measured the direction of the grain

Why is it important that you know these term?

- common communications in the classrooms and in industry

• Lumber dimensions are always given in this order….T x W x L ex. 2 x 4 x 8

But lumber dimensions are not what they seem! 2x4x8 is not 2” thick, 4” wide by 8’ long

It is 1 ½” thick, 3 ½”wide by 8’ long

Why? Because the wood needs to be dressed (smooth) and true (square) These are industry standards! STOCK - any piece of wood or lumber -rough or dressed - or sheet goodsTRUE - a piece of stock that is dressed and has these

qualities

* all surfaces are flat* all surfaces are smooth* all edges are 90° to the faces* all sides are parallel

How do we get dressed, true stock?

1. Cut to rough length - Radial Arm Saw2. Joint one side and one edge - Jointer3. Plane to finished thickness - Planer4. Cut to finished width - Table Saw5. Cut to finished length - Radial Arm Saw

or Chop Saw *trim off one end first and then cut to finished length

Radial Arm saw

1. Cut off all the end checks and defects (1” to 2”) 2. Measure the rough length (add 1” to finished length) with a tape measure

and square a line with a pencil and a square 3. Cut to rough length, on the waste side of the line! SAFETY RULES • Never cross your hands when cutting stock • Knock scrap pieces away with a scrap piece of wood• Never use your hands!

JointerNow we have a piece of stock that is cut to rough length! 1. Joint one side with the cup side down - safer and less waste * This will be called the ‘face side’ 2. Joint one edge with the face side against the fence SAFETY RULES

• Always push the stock all the way through until the guard snaps shut. • Never remove more than 1/16” in one pass • Always use a push stick when jointing face sides

• Always use a push stick when cutting the face edge, if the stock width is less than the height of the fence

• Never joint stock that is shorter than 16”

PlanerOur stock is now cut to rough length has one smooth side and a smooth edge!1. Measure the thickness of the stock and subtract 1/8” 2. Set the height of the planer table, using the scale on the side of the planer 3. Plane to this thickness making sure the face side is down 4. Keep following steps 2-4 until you have reached desired thickness

SAFETY RULES • Do not remove more than 1/8” in one pass • Do not look directly into the planer

• Do not reach into the planer to clear away the dust-use the air line or hand broom

• Keep your fingers on top of the stock, not underneath • Do not plane stock that is shorter than 16”

Table SawOur stock is now cut to rough length and finished thickness! 1. Set the fence to the desired finished width - measure from the inside of the blade to the fence 2. Cut to the finished width

SAFETY RULES • Always use the safety guards whenever possible • Never use the miter gauge and the fence at the same time - causes KICK BACK • Do not stand directly behind the blade - kick back • Use a push stick when ripping stock that is less than 8” in width • Use a helper when ripping long pieces of stock

– the helper should never pull the stock through the saw, only support the stock!

• only the operator controls the rate of stock feed