Lumber Measurement Lecture Notes PDF

LECTURE 5A: LUMBER MEASUREMENT LUMBER Product sawn from a log with thickness, width, and length. SAWMILLING Process of converting logs into lumber This process is done in a sawmill The volume of lumber is expressed in board foot. BOARD FOOT A plank of wood 1 inch thick and 1 ft squar...

LECTURE 5A: LUMBER MEASUREMENT LUMBER Product sawn from a log with thickness, width, and length. SAWMILLING Process of converting logs into lumber This process is done in a sawmill The volume of lumber is expressed in board foot. BOARD FOOT A plank of wood 1 inch thick and 1 ft square CONVERSION: BoardFoot = 1’ x 1’ x 1” 1’ x 1’ x (1/12) = 1/12 cu.ft. BoardFoot = 1’ x 1’ x 1” 12” x 12” x 1” = 144 cu.inches Since: FORMULA TO DERIVE THE VOLUME OF LUMBER IN BD FT. DIFFERENT WASTAGES IN SAWING A LOG INTO LUMBER: 1. Sawdust Fine particle of wood made by a saw in cutting 2. Slabs The outer pieces cut from squaring a log 3. Edgings Come from cutting boards or lumber with parallel and square sides: To remove bark or wanes To cut the lumber into desired width To remove defects along edge to improve quality of lumber 4. Trimmings Come from squaring the ends of the boards FACTORS AFFECTING BOARD FOOT CONTENT OF LOG: 1. Relative freedom from defects 2. Thickness of saws 3. Degree of waste from slabs/edgings -Logs are seldom straight and the heaviness of slabbing depends on a number of factors, the most important one is the relative straightness of the log or its freedom from crook, taper or sweep. 4. Thickness of lumber sawed 5. Width of lumber sawed -The narrower the boards, the less amount of material thrown out as slabs and edgings. 6. Skill of the sawyer -The less skillful man would give smaller board foot yield and high degree of waste. 7. The efficiency of the machinery -Band mills always have better lumber recovery while small portable mill with a thick circular headsaws provide a high degree of waste 8. The taper of the log -Tapering logs yield more board foot contents than logs with little taper. 9. Shrinkage -Shrinkage from the sawed-out dimensions should always be expected, hence, adjustments in lumber size should be made. LECTURE 5B: LOG RULES AND SCALING LOG RULES A table or formula showing the estimated volumes of lumber in board feet derived from a log with a given diameter and length under specified utilization standards. SCALING DIAMETER All of the log rules require the use of small-end diameter measured inside the bark and is expressed in inches, or sometimes called the SCALING DIAMETER. The length of the log should be expressed in feet and volume is on board feet. For example sa ⅛ ung length of log natin is 16 ft. edi ito 4,8,12,16 edi pag in draw apat ang hati tapos ang scaling diameter natin eh 41 and taper is.5 edi ganito 41,41.5,42 and 42.5 Then sa ¼ namn as 0.905 and then multiply sa volume mo. based sa sinabi ni mark. Kapag m ang length of given mo dapat convert mo sya into ft. Length of given m = 3.28084 ft. divide it 1m = ft. LOG SCALE It is the number of board feet obtained from a log rule for given diameter inside bark at the small end of the log and log length. Estimated lumber of volume MILL TALLY Is the actual amount of board feet sawed out of a log at the mill Actual lumber volume LECTURE 6: MEASUREMENT OF STACKED WOOD STACKED WOOD are bolts and sticks or shorter pieces of wood that are assembled in stacks Describe the wood products of smaller dimensions usually