Types, Uses and Care of Metalwork Hand Tools for JSS 1

Machines and Tools: Metal Work Hand Tools

Performance Objectives

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

1. identify different hand tools used for metalwork;
2. describe the hand tools;
3. draw sketches of the different hand tools;
4. make simple technology product like fixing fittings, screws, springs on wooden chair, stool using metal hand tools;
5. care and maintain metal work hand tools.

Introduction to Metalwork Hand Tools

Metalwork hand tools are manual instruments used to shape, measure, mark, cut or join metal materials without the use of electrical power.

In school workshops and local industries, these tools are essential for fabricating metal objects, repairing machinery and constructing simple structures. Hand tools rely entirely on the physical force and skill of the person using them. Understanding how to identify, describe and use these tools safely is the first step in metalwork technology.

The main categories of metalwork hand tools are:

1. Marking out tools
2. Measuring tools and gauges
3. Driving tools
4. Cutting tools

Marking Out Tools

Marking out tools are instruments used to transfer dimensions, lines and centres from a technical drawing directly onto the surface of a metal sheet or bar before cutting or shaping begins.

Accurate marking out ensures that metal parts are cut to the correct sizes and fit together properly during assembly.

Examples of marking out tools include:

1. Surface plate: A flat, highly polished cast-iron or granite block used as a reference plane for marking out and inspection. It provides an extremely level surface upon which metal workpieces and other marking tools are placed to ensure accuracy.
2. Scriber: A sharp, pointed steel tool used to scratch lines on the surface of metal. Because pencils do not write clearly on hard metal surfaces, the hardened steel tip of the scriber is used to make thin, permanent scratches that guide cutting and drilling.
3. Odd-leg calipers: A tool with one straight leg containing a guide tip and one bent leg, used to scribe lines parallel to an edge or to locate the centre of round metal bars.

Observe the diagram below to identify common marking out tools.

Measuring Tools and Gauges

Measuring tools and gauges are instruments used to determine the dimensions, sizes, lengths or angles of metal workpieces.

In metalwork, measurements must be highly precise, often down to the nearest millimetre, to prevent waste of materials.

Common measuring tools and gauges include:

1. Steel rule: A thin, flat strip of hardened steel marked with measurements used to measure lengths and guide straight lines. Unlike wooden or plastic rulers, a steel rule can withstand the rough edges of metal without being damaged.
2. Protractor: A semi-circular tool used to measure and mark out angles on metal surfaces. It is marked in degrees from 0 to 180, allowing workers to lay out angular cuts accurately.

Look at the measuring tools shown in the diagram below.

Driving Tools

Driving tools are instruments used to push, force, turn or hammer other objects into place during metalwork operations.

These tools are commonly used to tighten fasteners, punch holes or assemble metal components.

Examples of driving tools include:

1. Punches: A punch is a metal rod with a shaped tip used to make small indentations on metal surfaces. A centre punch has a 90-degree point and is struck with a hammer to create a small dimple that guides a drill bit, preventing it from slipping. A prick punch has a sharper 30-degree point used for marking out locations.
2. Screwdrivers: A screwdriver is a tool with a shaped tip used to tighten or loosen screws. Common types include the flat-head (slot) screwdriver and the Phillips (cross-head) screwdriver.
3. Spanners: A spanner is a tool with shaped openings or jaws used to turn nuts and bolts. They come in various sizes to match the specific dimensions of bolt heads.

Observe the driving tools illustrated below.

Cutting Tools

Cutting tools are instruments used to remove unwanted portions of metal by shearing, chipping, scraping or abrading.

Because metals are hard, cutting tools must be made of highly hardened steel to cut through workpieces without losing their sharp edges.

Common cutting tools include:

1. Chisels: A chisel is a hardened steel tool with a sharp cutting edge at one end, struck with a hammer to cut or chip cold metal. The cold chisel is the most common type used in metalwork workshops to cut sheet metal or chop off bolt heads.
2. Files: A file is a hardened steel bar with rough, raised teeth on its surface, used to smooth, shape or remove small amounts of metal. Files come in different shapes, such as flat, round, half-round and triangular, depending on the shape of the metal surface being worked on.

Look at the cutting tools shown in the diagram below.

Drawing and Sketching Metalwork Hand Tools

Sketching is an important skill in basic technology. It helps learners understand the shapes, parts and proportions of different tools.

The steps for sketching a simple hand tool are:

1. Observe the tool carefully to note its overall shape and proportions.
2. Draw light guidelines to represent the length and width of the tool.
3. Sketch the main body of the tool using firm, clean lines.
4. Add specific details, such as the handle, the pointed tip or the teeth.
5. Label the key parts of the tool clearly.

Observe the simple sketches below to guide drawing practice.

Care and Maintenance of Metalwork Hand Tools

Metalwork hand tools must be cared for and maintained regularly to keep them in good working condition, prevent rust and ensure safety during use.

Neglected tools can become blunt, rusty or broken, which makes work difficult and increases the risk of workshop accidents.

Important care and maintenance processes include:

1. Cleaning: Wipe tools with a clean rag after every use to remove metal filings, dirt and sweat.
2. Rust prevention: Apply a thin coat of light machine oil or grease to metal surfaces before storing them. This prevents moisture in the air from causing rust.
3. Proper storage: Store tools in designated toolboxes, drawers or on tool racks. Do not pile tools on top of each other, as this can blunt cutting edges or damage delicate measuring scales.
4. Correct usage: Use each tool only for its intended purpose. For example, a screwdriver should never be used as a chisel, and a steel rule should never be used as a pry bar.
5. Sharpening: Keep cutting tools like chisels sharp by grinding or honing them regularly. Blunt tools require more force to use and are more likely to slip and cause injury.

Practical Project: Making a Simple Technology Product

This practical project demonstrates how to use metal hand tools to fix metal fittings, screws and springs onto a wooden chair or stool. This activity combines woodwork and metalwork skills to repair or reinforce furniture.

The required materials are:

1. A wooden stool or chair requiring reinforcement
2. Metal corner brackets (fittings)
3. Wood screws
4. Tension or compression springs
5. A screwdriver matching the screw heads
6. A steel rule and a scriber
7. A centre punch and a small hammer

The procedure for fixing metal fittings on a wooden stool involves the following steps:

1. Positioning: Place the metal corner bracket at the joint of the wooden stool where reinforcement is needed.
2. Marking: Use a steel rule to align the bracket. Use a scriber to mark the exact positions of the screw holes on the wood.
3. Punching: Remove the bracket and use a centre punch and hammer to make a tiny indentation at each marked spot. This prevents the screw from slipping when starting to turn it.
4. Fixing the bracket: Place the metal bracket back over the indented marks. Insert a screw into one of the holes.
5. Driving the screw: Hold the screwdriver firmly. Place the tip of the screwdriver into the screw head and turn it clockwise to drive the screw into the wood. Repeat this for all the holes until the bracket is held tightly.
6. Attaching the spring: If the stool requires a spring mechanism, mark the attachment points on the underside of the seat. Fix the metal screw eyes or hooks using the same marking and driving process, then hook the spring securely onto the fittings.
7. Inspection: Shake the stool gently to ensure the metal fittings and springs are firm and secure. Clean the tools and return them to the storage rack.

Observe the assembly process shown below.

Summary

Metalwork hand tools are grouped into marking out, measuring, driving and cutting tools. Each group has a specific function in the workshop. Proper care, such as cleaning, oiling and correct storage, extends the lifespan of these tools and ensures safety. Applying these tools to simple projects, like reinforcing furniture, helps build practical technology skills.

Questions for Evaluation

Answer the following questions to test understanding of the lesson:

1. What are metalwork hand tools?
2. List the four main categories of metalwork hand tools and give two examples of each.
3. Describe the function of a scriber and explain why a pencil is not suitable for marking metal.
4. Explain the difference between a centre punch and a prick punch.
5. State three important care and maintenance processes for metalwork hand tools.
6. Describe the steps involved in fixing a metal bracket to a wooden chair using screws.