2 Characteristics of Wood Trees provide us with: · lumberplywoodPapermedical supplies and drugsAll trees are classified as either · hardwoodsoftwoodDeciduous trees (hardwoods) - shed their leaves at the endof the growing seasonEx. Oak, maple, cherry, ashConifer trees (softwoods) have needles and conesEx. Pine, spruce, fir, cedarAll types of wood vary in color, strength, mass and grain pattern.
3 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
4 Structures of Wood/SapwoodPith= 1 year of growthPith
5 Cutting and Milling Lumber 1. 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)Edgers (cut width) and trimmer saws (cut length) cut boards to proper widths and lengths.All the boards are then sorted, graded and dried.Drying Lumber - green lumber is 50% water dried lumber is 7-10% waterGrading - the grade of the lumber depends on the amount of defects in thewood- 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
6 Types of Warping in Lumber As wood/lumber dries weird things happen!BOWCUPTWISTCROOK
7 Natural Defects in Wood Pitch PocketStains and wood rotWorm/insect holesWane (bark)Pith
8 Types of Wood Knots Dead Knot -will fall out Live or Tight Knot – will not fall outbut may chipDead Knot -will fall out
9 Stock Thickness- measures the distance between the sides Width measures the distance between the edgesLength measures the distance between the ends- usually is measured the direction of thegrainWhy is it important that you know these term?- common communications in theclassrooms and in industryLumber dimensions are always given in this order….T x W x L ex. 2 x 4 x 8
10 But lumber dimensions are not what they seem! 2x4x8 is not 2” thick, 4” wide by 8’ longIt is 1 ½” thick, 3 ½”wide by 8’ longWhy? 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 thesequalities* all surfaces are flat* all surfaces are smooth* all edges are 90° to the faces* all sides are parallel
11 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 SawCut to finished length - Radial Arm Saw or Chop Saw*trim off one end first and then cut to finished length
12 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 square3. Cut to rough length, on the waste side of the line!SAFETY RULESNever cross your hands when cutting stock Knock scrap pieces away with a scrap piece of woodNever use your hands!
13 Jointer Now we have a piece of stock that is cut to rough length! Joint one side with the cup side down safer and less waste* This will be called the ‘face side’Joint one edge with the face side against the fenceSAFETY RULESAlways push the stock all the way through until the guard snaps shut.Never remove more than 1/16” in one passAlways use a push stick when jointing face sidesAlways use a push stick when cutting the face edge, if the stock width is less than the height of the fenceNever joint stock that is shorter than 16”
14 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 planer3. Plane to this thickness making sure the face side is down4. Keep following steps 2-4 until you have reached desired thicknessSAFETY RULESDo not remove more than 1/8” in one passDo not look directly into the planerDo not reach into the planer to clear away the dust-use the air line or hand broomKeep your fingers on top of the stock, not underneathDo not plane stock that is shorter than 16”
15 Table Saw Our 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 fence2. Cut to the finished widthSAFETY RULESAlways use the safety guards whenever possibleNever use the miter gauge and the fence at the same time - causes KICK BACKDo not stand directly behind the blade - kick backUse a push stick when ripping stock that is less than 8” in widthUse a helper when ripping long pieces of stockthe helper should never pull the stock through the saw, only support the stock!only the operator controls the rate of stock feed