Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 1st Term
Week: 1
Age: 16 years
Duration: 45 minutes
Subject: Metal Work
Curriculum Theme: Pre-Vocational Studies
Previous Lesson: Gas Welding Systems.
Topic: Metal Joining Processes
Subject Matter: Meaning of metal joining processes (methods of joining two or more metals together), temporary metal joining process (bolts, nuts, screws), permanent metal joining process (riveting), identification of common fasteners and their uses (bolt, nut, pin, screw)

Specific Objectives

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

Cognitive Domain:

Define metal joining processes.
Differentiate between temporary and permanent metal joining processes.
Identify at least three common fasteners and state their uses.

Affective Domain:

Appreciate the importance of proper metal joining in fabrication.
Demonstrate interest in learning practical metalwork skills.

Psychomotor Domain:

Participate in assembling metal pieces using bolts and nuts.
Correctly use basic hand tools like spanners for tightening fasteners.

Work cooperatively with peers during practical demonstrations.
Share tools and resources responsibly during practical tasks.

Reference Materials

The following resources were used in planning this lesson:

Senior Secondary Schools Education Curriculum
State Unified Scheme of Work
Metalwork Technology for Senior Secondary Schools by A.O. Olaitan

Instructional Materials

The teacher will teach this lesson with the aid of:

Mild steel plate
Various sizes of bolts and nuts
Drill machine
Spanners (open-end, ring, adjustable)
Screws
Pins
Safety goggles

Rationale for the Lesson

This lesson helps pupils understand how metal parts are put together in various structures and products. It enables them to identify different joining methods and fasteners, which is important for practical applications in engineering and everyday repairs.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of different types of metals and common hand tools used in metalwork.

Lesson Content/Board Summary

Metal Joining Processes

Meaning of Metal Joining Processes

Metal joining processes refer to various methods used to connect two or more separate metal parts to form a single assembly or structure. These processes are essential in manufacturing, construction, and repair.

Types of Metal Joining Processes

Metal joining processes can be broadly classified into two main types:

Temporary Metal Joining Processes: These methods allow for easy disassembly of the joint without damaging the original components.
Permanent Metal Joining Processes: These methods create a joint that is difficult or impossible to separate without destroying the components or the joint itself.

Temporary Metal Joining Processes

Temporary metal joining processes typically use mechanical fasteners to hold parts together. The joint can be undone using appropriate tools.

The following are common fasteners used in temporary metal joining:

Bolts: A threaded fastener with an external thread designed to pass through a hole in the components and be tightened by a nut. Bolts are generally used for through-hole applications.
Nuts: A type of fastener with a threaded hole used to secure a bolt. Nuts come in various shapes like hexagonal, square, or wing nuts.
Screws: A threaded fastener with an external thread designed to be driven into a material, creating its own thread or engaging with a pre-tapped hole. Screws are often used to join components directly without a nut.
Pins: Cylindrical or tapered fasteners inserted into holes in two or more parts to hold them in position relative to each other or to prevent relative movement. Examples include dowel pins, cotter pins, and clevis pins.

Permanent Metal Joining Processes

Permanent metal joining processes create strong, rigid joints that are not designed for easy disassembly.

An example of a permanent metal joining process is:

Riveting: A process where a metal fastener called a rivet is used to join two or more plates. The rivet is inserted through aligned holes, and its ends are deformed (headed or bucked) to create a permanent joint. Riveting is commonly used in aircraft construction, bridges, and structural steelwork.

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 asks them to identify how different metal parts of objects around them (e.g., chairs, desks, window frames) are held together. The teacher then introduces the topic: Metal Joining Processes.
Pupils’ Activity: Pupils respond by mentioning various methods they observe, such as welding, screws, or bolts. They listen attentively to the topic introduction.
Learning Point: Pupils recall prior observations and are introduced to the lesson topic.

Step 2: Meaning of Metal Joining Processes

Time: 8 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines metal joining processes as methods used to connect two or more metal parts to form a single assembly. The teacher explains its importance in manufacturing and construction.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition and purpose of metal joining processes.

Step 3: Types of Metal Joining Processes

Time: 8 minutes
Teaching Skill: Classification/Explanation
Teacher’s Activity: The teacher explains the two main types of metal joining processes: temporary and permanent. The teacher highlights that temporary joints can be disassembled without damage, while permanent joints cannot.
Pupils’ Activity: Pupils listen, observe the teacher’s examples, and differentiate between the two types.
Learning Point: Pupils learn to distinguish between temporary and permanent metal joining methods.

Step 4: Temporary Metal Joining Processes (Fasteners)

Time: 8 minutes
Teaching Skill: Identification/Description
Teacher’s Activity: The teacher introduces common fasteners used in temporary joining, such as bolts, nuts, screws, and pins. The teacher shows samples of each fastener and explains their specific uses and characteristics.
Pupils’ Activity: Pupils observe the displayed fasteners, identify them, and note their uses.
Learning Point: Pupils identify common fasteners and understand where each is used.

Step 5: Demonstration of Temporary Joining

Time: 8 minutes
Teaching Skill: Demonstration/Practical Application
Teacher’s Activity: The teacher demonstrates how to join two pieces of mild steel plate using a bolt and nut. This involves drilling holes, aligning the plates, inserting the bolt, and tightening the nut with a spanner. The teacher emphasizes safety.
Pupils’ Activity: Pupils observe the demonstration carefully, identify the tools used, and note the steps involved. Some pupils may assist or try under supervision.
Learning Point: Pupils gain practical understanding of how temporary joints are made using fasteners.

Step 6: Permanent Metal Joining (Riveting)

Time: 3 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher briefly introduces riveting as a permanent metal joining process. The teacher explains that rivets are used to create joints that are not easily disassembled without destroying the rivet.
Pupils’ Activity: Pupils listen and understand the concept of permanent joining through riveting.
Learning Point: Pupils are introduced to a common permanent metal joining method.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

What is meant by metal joining processes?
Differentiate between temporary and permanent metal joining processes.
Mention three common fasteners used in temporary metal joining.
State one use for a bolt and one use for a screw.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definition of metal joining, the types of processes, and the identification of common fasteners. The teacher assigns homework: “List five everyday items that use temporary metal joining processes.”
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of the lesson and prepare for further study.

Lesson Keywords

Metal joining – The process of connecting two or more metal parts.
Temporary joint – A joint that can be easily disassembled without damaging the parts.
Permanent joint – A joint that cannot be easily disassembled without damaging the parts or the joint.
Fastener – A device used to mechanically join or affix two or more objects together.
Bolt – A threaded fastener used with a nut to join parts.
Nut – A threaded fastener that mates with a bolt.
Screw – A threaded fastener that can create its own thread or engage a pre-tapped hole.
Rivet – A permanent fastener used to join plates by deforming its ends.

Differentiation

The teacher will provide visual aids of different fasteners for visual learners. Practical demonstration will cater to kinesthetic learners. Group discussions and question-and-answer sessions will support auditory learners. Pupils requiring additional support will be paired with more knowledgeable peers during the practical demonstration, and the teacher will provide individualized attention.

Note for teachers using this lesson plan

Teachers should ensure all safety precautions are taken during the drilling and assembly demonstration, including the use of safety goggles. Encourage pupils to actively participate and ask questions. Have various fasteners available for pupils to touch and examine. Emphasize the practical relevance of metal joining in various industries.