Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 3
Age: 15 years
Duration: 45 minutes
Subject: Metal Work
Curriculum Theme: Pre-Vocational Studies
Previous Lesson: Drill Press: Parts, Capacity and Reaming.
Topic: Types of Drilling Machine
Subject Matter: sensitive drilling machine, upright drilling machine, radial drilling machine, multiple drill heads, turret drilling machine, drilling operation steps, difference between drilling and reaming

Specific Objectives

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

Cognitive Domain:

Identify and describe various types of drilling machines.
Explain the steps involved in a drilling operation.
Differentiate between drilling and reaming processes.

Affective Domain:

Appreciate the importance of selecting the correct drilling machine for specific tasks.
Value precision and safety in drilling operations.

Psychomotor Domain:

Sketch simple diagrams of different drilling machines.
Outline the sequence of steps for a basic drilling operation.

Discuss the applications of different drilling machines in a workshop setting.
Collaborate with peers to identify components of drilling machines.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Technology (JSS 1-3)
State Unified Scheme of Work for Metal Work SSS 1
Metal Work Technology for Senior Secondary Schools by E.A. Adewuyi

Instructional Materials

The teacher will teach this lesson with the aid of:

Pictures and diagrams of various drilling machines (sensitive, upright, radial, multiple drill heads, turret)
Samples of metal sheets with drilled and reamed holes
Workshop demonstration tools (e.g., drill bits, reamers)

Rationale for the Lesson

This lesson helps pupils understand the different types of drilling machines used in metalwork and their specific applications. Knowing these machines and the correct drilling steps enables pupils to perform tasks accurately and safely, preparing them for practical workshop activities and future technical careers.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of hand tools, workshop safety rules, and the concept of making holes in materials.

Lesson Content/Board Summary

Types of Drilling Machine

Sensitive Drilling Machine

A sensitive drilling machine is a light-duty machine designed for small, precise holes. It is called “sensitive” because the operator can “feel” the cutting action of the drill bit as it cuts into the workpiece, allowing for precise control.

Key features include a hand-fed spindle and a small work table.

Upright Drilling Machine

An upright drilling machine, also known as a pillar drilling machine, is a medium-duty machine used for general purpose drilling. It is larger and more robust than a sensitive drilling machine, capable of drilling larger holes and handling heavier workpieces.

It typically has a geared head or belt-driven spindle and a larger work table that can be adjusted vertically.

Radial Drilling Machine

A radial drilling machine is a heavy-duty machine designed for drilling large holes in heavy and bulky workpieces. Its main characteristic is a radial arm that can swing around a column, allowing the drill head to be positioned over a wide area of the workpiece without moving the workpiece itself.

This machine is ideal for large fabrications and structural work.

Multiple Drill Heads

Multiple drill head machines are designed to drill several holes simultaneously in a workpiece. They consist of a single machine with multiple spindles, each holding a drill bit.

This type of machine increases productivity, especially in mass production.

Turret Drilling Machine

A turret drilling machine is equipped with a rotating turret that holds several different drill bits or tools. This allows the operator to quickly switch between different drilling or reaming operations without manually changing tools.

It is often used in production lines where a sequence of operations is required on a single workpiece.

Steps in Drilling Operation

The following are the general steps involved in a drilling operation:

Marking the workpiece: Accurately mark the center of the hole to be drilled using a scriber and punch.
Securing the workpiece: Clamp the workpiece firmly to the machine table using a vise or clamps to prevent movement during drilling.
Selecting the drill bit: Choose the correct size and type of drill bit for the material and desired hole diameter.
Mounting the drill bit: Securely insert the drill bit into the drill chuck.
Setting the spindle speed: Adjust the machine’s spindle speed according to the material being drilled and the drill bit diameter.
Positioning the workpiece: Align the center punch mark on the workpiece directly under the tip of the drill bit.
Starting the machine: Turn on the drilling machine.
Drilling the hole: Carefully feed the drill bit into the workpiece, applying steady pressure. Use cutting fluid if necessary.
Clearing chips: Periodically withdraw the drill bit to clear chips and allow coolant to reach the cutting edge.
Completing the hole: Continue drilling until the desired depth or through-hole is achieved.
Retracting the drill: Slowly withdraw the drill bit from the hole.
Switching off the machine: Turn off the drilling machine.
Deburring: Remove any sharp edges (burrs) from the drilled hole.

Difference between Drilling and Reaming

Drilling and reaming are both hole-making operations, but they serve different purposes:

Drilling: This is the process of creating a hole in a material using a drill bit. Drilled holes are generally rough and not highly accurate in terms of diameter or surface finish.
Reaming: This is a finishing operation used to enlarge a pre-drilled or cored hole to a precise diameter with a smooth surface finish. Reaming removes a small amount of material and improves the accuracy and surface quality of the hole.

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 recall some tools used for making holes in metal. The teacher then introduces the topic by stating that machines are also used to make holes, especially when precision or larger holes are required.
Pupils’ Activity: Pupils respond to questions and listen attentively.
Learning Point: Pupils recall previous knowledge and are introduced to the lesson topic.

Step 2: Presentation of Sensitive Drilling Machine

Time: 7 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher explains what a sensitive drilling machine is, its main features, and its typical uses, showing pictures or diagrams. The teacher emphasizes its use for small, precise holes.
Pupils’ Activity: Pupils listen, observe the diagrams, and ask questions for clarification.
Learning Point: Pupils understand the characteristics and application of a sensitive drilling machine.

Step 3: Presentation of Upright and Radial Drilling Machines

Time: 8 minutes
Teaching Skill: Explanation/Comparison
Teacher’s Activity: The teacher explains the upright drilling machine, highlighting its differences from the sensitive type. The teacher then introduces the radial drilling machine, explaining its unique arm design and suitability for heavy, bulky workpieces. Comparisons are made between the three types discussed so far.
Pupils’ Activity: Pupils listen, observe, and identify the distinctions between the machines.
Learning Point: Pupils can differentiate between sensitive, upright, and radial drilling machines and state their uses.

Step 4: Presentation of Multiple Drill Heads and Turret Drilling Machine

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher describes the function and advantages of multiple drill head machines for simultaneous drilling. The teacher then explains the turret drilling machine, focusing on its tool-changing capability and efficiency in production.
Pupils’ Activity: Pupils listen and understand the specialized applications of these drilling machines.
Learning Point: Pupils learn about specialized drilling machines for increased productivity and versatility.

Step 5: Drilling Operation Steps

Time: 8 minutes
Teaching Skill: Instruction/Demonstration
Teacher’s Activity: The teacher outlines and explains the step-by-step procedure for a safe and effective drilling operation. If possible, a brief practical demonstration using a small hand drill or visual aids is given.
Pupils’ Activity: Pupils listen, take notes, and observe the demonstration, asking questions about the steps.
Learning Point: Pupils learn the correct sequence and safety measures for drilling.

Step 6: Difference between Drilling and Reaming

Time: 5 minutes
Teaching Skill: Explanation/Clarification
Teacher’s Activity: The teacher explains the distinct purposes of drilling and reaming, emphasizing that drilling creates a hole while reaming refines it for accuracy and finish. Samples of drilled and reamed holes are shown.
Pupils’ Activity: Pupils observe the samples and understand the difference between the two processes.
Learning Point: Pupils can distinguish between drilling and reaming operations.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

List three types of drilling machines discussed in class.
State one specific application for a radial drilling machine.
Mention two important steps to follow when performing a drilling operation.
Explain the main difference between drilling and reaming.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the different types of drilling machines, their uses, drilling steps, and the distinction between drilling and reaming. The teacher assigns homework: “Draw and label any two types of drilling machines learned today.”
Pupils’ Activity: Pupils listen to the summary and copy the homework.
Learning Point: The lesson is concluded, and pupils are given a task to reinforce learning.

Lesson Keywords

Sensitive Drilling Machine – A light-duty drilling machine for small, precise holes where the operator can feel the cutting action.
Upright Drilling Machine – A medium-duty drilling machine for general purpose hole making, also known as a pillar drill.
Radial Drilling Machine – A heavy-duty drilling machine with a movable arm, used for large and heavy workpieces.
Multiple Drill Heads – A machine designed to drill several holes simultaneously using multiple spindles.
Turret Drilling Machine – A drilling machine equipped with a rotating tool holder (turret) for quick tool changes.
Drilling – The process of creating a hole in a material using a rotating cutting tool (drill bit).
Reaming – A finishing operation to enlarge and smooth a pre-drilled hole to a precise diameter.

Differentiation

For pupils who grasp concepts quickly, the teacher will encourage them to research advanced features of CNC drilling machines. For those needing more support, the teacher will provide simplified diagrams and one-on-one explanations, focusing on identifying the most common drilling machine types and basic safety steps.

Note for teachers using this lesson plan

Ensure that actual pictures or videos of the drilling machines are available to enhance understanding. Emphasize safety precautions in the workshop, especially when discussing drilling operations. If possible, a field trip to a school workshop or a local fabrication shop would provide valuable practical exposure.