civil evolution
PRESERVATION OF TIMBER Timber has to be preserved from moisture, dry rot or internal decay and from the attacks ofinsects. Paint on seasoned timber preserves it from moisture and extends its life indefinitely ifrenewed periodically. Many processes has been adopted for protecting the timber from dry rot andinsects by impregnating it with chemical substances. Tarring,…
STORAGE OF TIMBER The converted timbers should be properly stored. For the purpose of storage, suitable stacks of timber pieces are formed. The timber pieces are arranged in layers and the layers are separated by wooden spacers. The stock is protected from direct sun, dry wind and rain. The image explains more than the words…
CONVERSION OF TIMBER The cutting up of timber to form planks, battens, etc. of required sizes by saw is called conversion. Power machines are employed in several stages when working on a large scale. During conversion the allowance should be made for shrinkage, squaring and planning. It is about 3 mm to 6 mm. The…
SEASONING OF TIMBER When a tree is newly felled, it contains about 50 percent or more of its own dry weight as water. This water is in the form of sap and moisture. The water is to be removed before the timber can be used for any engineering purpose. The timber is to be dried….
MARKET FORMS OF TIMBER The various market forms in which the timber is cut and sold are as follows: 1. Log 2. Deal 3. Baulk 4. Batten 5. Boards 6. Plank 7. End 8. Scantling 9. Pole 10. Post 11. Strips 12. Quartering or squares 1. Log: It is the trunk of a timber tree…
DEFECTS IN TIMBER The defects occurring in the timber are grouped into the following five divisions: 1. Defects due to fungi2. Defects due to insects.3. Defects due to seasoning.4. Defects due to natural forces.5. Defects due to conversion 1) Defects due to fungi: The fungi are minute microscopic plane organisms. Following defects are caused in…
Classification of Timber Depending upon their mode of growth trees may be divided into the following categories: 1)Exogenous trees: These trees increases in bulk by growing outwards and distinct consecutive rings are formedin the horizontal section of such a tree. These rings are known as the annual rings because one suchring is added every year…