Wastage of timber is the maximum in the case of:
The Sawing Trade-Off: Waste vs. Quality
When converting a round log into rectangular boards, some wood is inevitably lost as sawdust and odd-shaped offcuts. The method of sawing determines the balance between maximizing the usable lumber (yield) and achieving desirable grain patterns and structural stability. Generally, simpler methods have less waste but produce lower-quality timber, while complex methods that produce high-quality, stable timber do so at the cost of greater wastage.
📝 Detailed Analysis of the Options
(a) Ordinary sawing
Also known as flat sawing, this method involves making simple, parallel cuts through the log. It is the fastest method and produces the least amount of waste, maximizing the yield of lumber. This makes it the most economical method, but the resulting boards are more prone to warping.
(b) Tangential sawing
This is a specific method where cuts are made tangentially to the annual rings. Wastage is generally higher than ordinary sawing but less than the more complex radial or quarter sawing methods.
(c) Radial sawing
This is the correct answer. Also known as rift sawing, this method involves making cuts radially from the center of the log, like spokes on a wheel. This process creates many wedge-shaped offcuts from between the boards, resulting in the maximum amount of waste. The trade-off is that it produces extremely stable timber with a straight grain that is highly resistant to warping and shrinkage, making it desirable for high-end applications like furniture and flooring.
(d) Quarter sawing
In this method, the log is first cut into quarters. Each quarter is then sawn to produce boards with the annual rings mostly perpendicular to the faces. This method produces high-quality, stable wood but involves more handling and creates more waste than ordinary sawing, though typically less waste than radial sawing.
📊 Sawing Methods: Waste vs. Quality
| Sawing Method | Wastage Level | Quality & Stability | Cost |
|---|---|---|---|
| Radial Sawing | Maximum | Highest (Very stable, straight grain) | Highest |
| Quarter Sawing | High | High (Stable, attractive grain) | High |
| Tangential Sawing | Moderate | Good | Moderate |
| Ordinary Sawing | Minimum | Lowest (Prone to warping) | Lowest |
💡 Study Tips
- Radial = Radiating Waste: Think of the cuts radiating from the center of the log. This process naturally creates wedge-shaped waste between each board, leading to the highest wastage.
- Waste is the Price of Quality: Remember the inverse relationship: to get the highest quality, most stable wood (from radial sawing), you have to accept the highest amount of waste.
- Ordinary is Opposite: Ordinary sawing is the opposite of radial sawing in every respect: minimum waste, lowest quality, and lowest cost.