Pick up the correct statement from the following method of sawing timber ..........
Timber Conversion: The Art of Sawing
Conversion is the process of sawing a felled log into usable lumber. The method used is critical as it affects the final board's strength, stability (resistance to warping), appearance, and the amount of waste produced. Different methods are chosen to balance these factors based on the type of wood and its intended use.
📝 Detailed Analysis of the Statements
(a) Tangential sawing method
This statement is correct. In this method, the saw cuts are made tangential to the annual rings. It is the fastest and most economical method with the least waste, but the resulting planks are prone to warping and shrinking during seasoning.
(b) Quarter sawing method
This statement is correct. The log is first sawn into four quarters. Then, boards are sawn from each quarter such that the annual rings intersect the face of the board at an angle of 45° or more. This produces stable wood with an attractive grain but is more wasteful than tangential sawing.
(c) Radial sawing
This statement is correct. In this method, the cuts are made radially, parallel to the medullary rays and perpendicular to the annual rings. This produces the most dimensionally stable and durable timber with minimal shrinkage and warping. However, it is the most wasteful and expensive method.
(d) All options are correct
This is the correct answer. Each of the statements (a), (b), and (c) accurately describes the specific sawing method it is named after. Therefore, all the options are correct descriptions of different timber conversion techniques.
📊 Comparison of Sawing Methods
| Method | Description of Cut | Pros | Cons |
|---|---|---|---|
| Tangential | Tangential to annual rings | Fast, economical, least waste | Prone to warping and shrinkage |
| Quarter | Cuts at ≥ 45° to annual rings | Stable, attractive grain | More wasteful than tangential |
| Radial | Parallel to medullary rays | Most stable, strongest, minimal warping | Most wasteful, most expensive |
💡 Study Tips
- Visualize the Cuts: Try to picture a circular log and how the saw would pass through it for each method. Tangential (skimming the rings), Radial (like spokes of a wheel), and Quarter (cutting from the corners of a wedge).
- Link Method to Quality: Remember the trade-off: The more stable and high-quality the wood (Radial > Quarter > Tangential), the more wasteful and expensive the process is.
- Know the Definitions: The definitions provided in the options are the standard technical descriptions for each sawing method.