|
Wednesday, August 19, 2015
[Important] 1000's of woodworking plans here
| Click Here ToUnsubscribe  |
been an important construction material since humans began building shelters, houses and boats. Nea rly all boats were made lv9 out of wood until the late 19th century, and wood lv9 remains in common use today in bo at construction. Elm in particular was used for this purpose as it resisted decay as long as it was kept w et (it also 9served for water pipe lv9 mbefore the advent of more modern plumbing). Wood to be used for construction work is commonly known as lumber in North A v9merica. Elsewhere, lumber usua lly refers to felled trees, and the word for sawn planks ready for use is timber. In Medieval Europe oak wa s the wood of choice for all wood co pdzlv9 nstruction, including beams, walls, doors, and floors. Today a wider va riety of woods is used: solid wood doors are often made from poplar, small- pdzlv9 knotted pine, and Douglas fir. se-porous woods, the 9 demarcation between rings is not always s v9mo clea dzlv9 r and in some cases is almost (if not entirely) invisible to the unaided eye. Conversely, when therev is a clear demarcation there may not be a not iceable difference in structure within the growth ring. e rings are wide, the transition from spring wood to summer wood is gradual, while in the narrow rings the s pring wood passes in lv9 to summer wood abruptly. T lv9 he width of the spring wood changes but little with the width o f the annual ring, so that the narr dzlv9 owing or broadening of the annual ring is always pdzlv9 at the expense of the su mmer wood. The narrow vessels of the summer wood make it richer in wood substanc lv9 e than the spring wood compose d of wide vessels. Therefore, rapid 9-growing spec pdzlv9 imens with wide rings have more wood substance than slow-growi ng trees with narrow rings. Since the more the wood substance the greater the weight, and the greater the weig ht the stronger the lv9 wood, chestnuts with wid v9me rings must dzlv9 have stronger wood than chestnuts with narrow rings. This agrees with the accepted view that sprouts (which always have wide rings) yield b lv9 lv9 etter and stronger wood than seedling chestnuts, which gr In diffuse-porous woods, as has been stated, the vessels or pores are even-sized, so that the water conductin g capability is sca v9mttered throughout the ring instead of collected in the earlywood. The effect of rate of gro wth is, therefore, not the same as in the ring-porous woods, approaching more nearly the conditions in the coni fers. In general it may be stated that such woods lv9 of medium growth 9 afford stronger material than when very rapi dly or very slowly grown. pdzlv9 In many uses of wood, total strength is not the main consideration. If ease of workin g is prized, wood should be chosen with regard to its uniformity of texture dzlv9 and straightness of grain, which wi ll in most cases occur when there dzlv9 is little contrast betw pdzlv9 een the latewood of one season's growth and the earlywoo The churches of Kizhi, Russia are among a handful of World Heritage Sites built entirely of wood, without meta l joints. See Kizhi Pogost for more details. New domestic h v9mousing in dzlv9 many parts of the world today is commonly made from ti 9mber-framed construction. Engine red wood products are becoming a bigger part of the con lv9 struction industry. They may be used in both resident ial and commercial buildings as structural and aesthetic materials. In buildings made of other materials, wood will still be found as
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment