Lesson Note on Methods Of Timber Conversion: Types And Processes for SS1

Class: Senior Secondary School 1 (SS1 / SSS1)
Term: Second Term
Week: 5
Age: 15 years
Duration: 45 minutes
Subject: Furniture Making
Curriculum Theme: Trade
Previous Lesson: Conversion Of Timber: Meaning And Methods.
Topic: Methods of Timber Conversion
Subject Matter: Sawing method, Rotary method, Slicing method, Conversion process steps

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Define timber conversion.
• Name the three main methods of timber conversion.
• Describe the sawing method of timber conversion.
• Describe the rotary method of timber conversion.
• Describe the slicing method of timber conversion.
• List the steps involved in the timber conversion process.

Affective Domain:

• Appreciate the importance of proper timber conversion techniques.
• Value the different methods used in converting timber.

Psychomotor Domain:

• Sketch the basic setup for one or more timber conversion methods.
• Identify the products of different conversion methods, such as veneer sheets.

Social Domain:

• Participate actively in class discussions on timber conversion.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum for Basic Technology (JSS 1-3) / Senior Secondary Education Curriculum for Trade Subjects.
• State Unified Scheme of Work for Senior Secondary School 1 (Furniture Making).
• Woodwork Technology for Senior Secondary Schools.
• https://www.wood-database.com/wood-articles/wood-conversion-methods/
• https://www.britannica.com/technology/wood-processing/Sawmilling

Instructional Materials

The teacher will teach this lesson with the aid of:

• Pictures or charts showing different timber conversion methods.
• A circular saw (model or diagram).
• A log carriage (model or diagram).
• Samples of veneer sheets.
• Whiteboard and markers.

Rationale for the Lesson

This lesson helps pupils to understand how raw logs are processed into usable timber for furniture making and other construction purposes. Understanding these methods enables pupils to appreciate the transformation of wood and the different products that can be obtained.

Prerequisite/Previous Knowledge

Pupils are expected to have some basic knowledge of different types of timber and their uses in furniture making.

Lesson Content/Board Summary

Methods of Timber Conversion

Definition of Timber Conversion

Timber conversion is the process of cutting raw logs into usable forms such as planks, boards, or veneers. This process aims to maximize yield and produce timber suitable for various construction and furniture-making purposes.

Methods of Timber Conversion

There are three main methods of timber conversion:

• Sawing Method
• Rotary Method
• Slicing Method

1. Sawing Method

This method involves cutting logs into planks, boards, or beams using various types of saws (e.g., circular saws, band saws). It is the most common method for producing solid timber.

Types of sawing patterns include:

• Through and through sawing (plain sawing)
• Quarter sawing
• Tangential sawing
• Radial sawing

2. Rotary Method (Peeling Method)

The rotary method involves rotating a log against a long blade, peeling off continuous thin sheets of wood, known as veneers. This method is primarily used to produce veneers for plywood and decorative surfaces.

3. Slicing Method

The slicing method involves moving a log or flitch (part of a log) against a stationary blade, or moving the blade across the log, to produce individual thin sheets of veneer. This method is often used for high-quality decorative veneers where specific grain patterns are desired.

Steps in the Timber Conversion Process

The general steps involved in converting timber from logs to usable forms include:

• Debarking: Removing the bark from the log.
• Cross-cutting: Cutting the log into desired lengths.
• Sawing/Peeling/Slicing: The actual conversion process using one of the methods.
• Edging: Squaring the edges of planks or boards.
• Trimming: Cutting the ends of timber to remove defects and achieve final length.
• Grading: Classifying timber based on quality, size, and species.
• Seasoning: Drying the timber to reduce moisture content.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and reviews the previous lesson. The teacher then introduces the new topic by asking pupils how raw logs are turned into furniture.
Pupils’ Activity: Pupils respond to the questions and listen attentively to the introduction.
Learning Point: Pupils are prepared for the new lesson.

Step 2: Presentation of Sawing Method

Time: 8 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains the sawing method of timber conversion, describing how logs are cut into planks and boards using saws. The teacher uses diagrams or pictures to illustrate different sawing patterns.
Pupils’ Activity: Pupils listen, observe the diagrams, and ask questions for clarification.
Learning Point: Pupils understand the sawing method and its variations.

Step 3: Presentation of Rotary Method

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains the rotary method, emphasizing that it produces continuous thin sheets of veneer by peeling a rotating log. The teacher shows samples of veneer sheets.
Pupils’ Activity: Pupils listen, observe the veneer samples, and note down key points.
Learning Point: Pupils understand the rotary method and its product (veneer).

Step 4: Presentation of Slicing Method

Time: 7 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher explains the slicing method, comparing it with the rotary method and highlighting its use for high-quality decorative veneers. The teacher may sketch the basic principle.
Pupils’ Activity: Pupils listen, compare the methods, and observe the sketches.
Learning Point: Pupils understand the slicing method and its specific application.

Step 5: Discussion of Conversion Process Steps

Time: 8 minutes
Teaching Skill: Discussion/Elicitation
Teacher’s Activity: The teacher leads a discussion on the general steps involved in timber conversion, from debarking to seasoning. The teacher writes the steps on the board as pupils contribute.
Pupils’ Activity: Pupils participate in the discussion, contributing ideas, and copying the steps from the board.
Learning Point: Pupils identify and understand the sequence of timber conversion steps.

Step 6: Practical Observation/Sketching

Time: 5 minutes
Teaching Skill: Practical Application
Teacher’s Activity: The teacher guides pupils to sketch one of the conversion methods or identify the parts of a log carriage/circular saw from diagrams.
Pupils’ Activity: Pupils attempt to sketch or identify parts as instructed by the teacher.
Learning Point: Pupils develop practical understanding and observation skills.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define timber conversion.
2. Mention three methods of timber conversion.
3. Describe the rotary method of timber conversion.
4. List any four steps involved in the timber conversion process.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, re-emphasizing the importance of timber conversion methods. The teacher then gives homework.
Homework: Draw and label the process of rotary timber conversion.
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their learning and receive further practice.

Lesson Keywords

• Timber Conversion – The process of cutting raw logs into usable forms.
• Sawing Method – Cutting logs into planks or boards using saws.
• Rotary Method – Peeling continuous thin sheets of veneer from a rotating log.
• Slicing Method – Producing individual thin sheets of veneer by moving a log against a blade.
• Veneer – Thin sheets of wood, often used for plywood or decorative surfaces.
• Debarking – Removing the bark from a log.
• Seasoning – Drying timber to reduce its moisture content.

Differentiation

For pupils who are struggling, the teacher will provide simplified diagrams and offer one-on-one explanations. For advanced pupils, the teacher will encourage them to research and present on the advantages and disadvantages of each conversion method.

Note for teachers using this lesson plan

Teachers should ensure they have clear visual aids or actual samples of wood products (planks, veneers) to make the lesson more concrete. Encourage pupils to ask questions and relate the lesson to real-life applications in their environment.