Qualities of Good Timber
Following are the characteristics or qualities of a good timber:
1. Appearance quality of Good Timber:
- A freshly cut surface of timber should exhibit hard and shining appearance.
2. Colour quality of Good Timber :
- The colour of timber should preferably be dark. The light colour usually indicates timber with low strength.
3. Defects quality of Good Timber:
- A good timber should be free from serious defects, e.g., dead knots, fl aws, shakes, etc.
4. Durability quality of Good Timber:
- A good timber should be durable. It should be capable of resisting the actions of fungi insects, chemicals, physical agencies and mechanical agencies.
5. Elasticity quality of Good Timber:
- This is the property by which timber returns to its original shape when load causing its deformation is removed. This is a sought after property of timber when it is used for making bow, carriage shafts, sport goods, etc.
6. Fibres quality of Good Timber:
- The timber should have straight fibres.
7. Fire resistance quality of Good Timber:
- The timber is a bad conductor of heat. A dense wood off ers good resistance to the fire and it requires sufficient heat to cause a flame.
8. Hardness quality of Good Timber:
- A good timber should be hard, i.e., it should off er resistance when penetrated by another body.
9. Mechanical wear quality of Good Timber:
- A good timber should not deteriorate easily due to mechanical wear or abrasion.
10. Shape quality of Good Timber:
- A good timber should be capable of retaining its shape during conversion or seasoning. It should not bow or warp or split.
11. Smell quality of Good Timber:
- A good timber should have sweet smell. An unpleasant smell indicates a decayed timber.
12. Sound quality of Good Timber:
- A good timber should give out a clear ringing sound when struck. A dull heavy sound, when struck, indicates a decayed timber.
- The velocity of sound in wood varies between 2–17 times greater than that in air and hence, the wood may be considered high in sound transmission.
13. Strength quality of Good Timber:
- A good timber should be strong for working as structural member, such as joist, beam, rafter, etc.
14. Structure quality of Good Timber:
- It should be uniform. The fibres should be firmly added.
- The medullary rays should be hard and compact.
15. Toughness quality of Good Timber:
- A good timber should be tough,
- i.e., it should be capable of offering resistance to the shocks caused due to vibrations.
16. Water permeability quality of Good Timber:
- A good timber should have low water permeability which is measured by the quantity of water filtered through a unit surface area of specimen of wood.
17. Weathering effects quality of Good Timber:
- A good timber should be able to reasonably withstand the weathering effects.
- When timber is exposed to weather, its colour normally fades and slowly turns grey.
