3.3
Legname
Il legname deriva da tronchi che vengono raccolti, scortecciati e lavorati in lunghi pezzi con una sezione trasversale rettangolare. La trasformazione…
I pezzi di legno lunghi e rettangolari utilizzati nella costruzione sono chiamati legname.
I tronchi raccolti dagli alberi vengono scortecciati e alimentati ripetutamente attraverso una sega automatizzata.
Ogni volta che il tronco viene tagliato, le lastre vengono trasportate tramite nastro trasportatore a seghe più piccole. Qui, le lastre vengono tagliate in legname a bordi quadrati delle larghezze richieste.
In questa fase, i pezzi tagliati hanno superfici ruvide e le loro dimensioni possono differire leggermente da un'estremità all'altra.
Il legname si ottiene mediante segatura a raso o a quarto. Il legname segato a piano ritrae gli anelli di crescita degli alberi piatti sulla faccia più larga della tavola ed è tipicamente utilizzato come legname strutturale.
Nel legname segato a quarti, gli anelli di crescita si allineano a circa 45 gradi o più nei legni teneri e a 60 gradi o più nei legni duri rispetto alla faccia più larga della tavola. Il legno tenero Quartersawn viene utilizzato per pavimenti, finiture e rivestimenti.
Il riftsawing viene utilizzato anche per i legni duri, con gli anelli di crescita in legno duro riftsawn allineati con un angolo da 30 a 60 gradi rispetto alla faccia larga della tavola e utilizzati dove l'aspetto e la durata sono essenziali.
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Q1: What is the basic process for converting logs into lumber?
Logs are harvested from trees, debarked, and fed through an automated saw that slices them into slabs. These slabs travel via conveyor belt to smaller saws, where they are cut into square-edged lumber of specific widths. The resulting pieces have rough surfaces and may vary slightly in dimensions from end to end.
Q2: How does plainsawing differ from quartersawing in lumber production?
Plainsawn lumber displays growth rings nearly flat on the board's wider face and is used primarily for structural applications due to cost-effectiveness. Quartersawn lumber aligns growth rings at approximately 45 degrees in softwoods and 60 degrees in hardwoods to the board's wider face, offering enhanced stability and appearance for flooring, trim, and siding applications.
Q3: What are the characteristics and uses of quartersawn lumber?
Quartersawn lumber features growth rings aligned at 45 degrees or more in softwoods and 60 degrees or more in hardwoods relative to the board's wider face. This cutting method produces lumber with enhanced stability and superior appearance, making it ideal for flooring, trim, and siding where durability and aesthetic appeal are important.
Q4: When is riftsawing used, and what advantages does it provide?
Riftsawing is primarily applied to hardwoods, aligning growth rings at 30 to 60-degree angles to the board's wide face. This technique optimizes both aesthetic appeal and durability, making riftsawn lumber ideal for high-quality furnishings and decorative applications where appearance and durability are essential.
Q5: Why do different lumber cutting methods affect wood quality and applications?
The cutting method significantly influences lumber's characteristics, stability, and appearance. Plainsawing maximizes efficiency and cost-effectiveness for structural use, while quartersawing and riftsawing enhance stability and aesthetics for specialized applications. Each technique caters to different construction and woodworking industry needs and requirements.
Q6: What happens to lumber immediately after it is cut from logs?
After cutting, lumber pieces have rough surfaces and their dimensions may vary slightly from one end to the other. The pieces require further processing, including surfacing and potentially seasoning, before they meet final specifications for construction or woodworking applications and use.
Q7: How do softwoods and hardwoods differ in their quartersawing angles?
In quartersawn lumber, softwoods have growth rings aligned at approximately 45 degrees to the board's wider face, while hardwoods require alignment at 60 degrees or more. This difference in angle requirements reflects the distinct structural properties and dimensions lumber must meet for different applications.