1. ✒️ Scriber

• 🔹 Description: A sharp steel tool used like a pen

• 🔹 Use: For drawing fine lines on metal surfaces

• 🔹 Tip: Hold it at a low angle for better accuracy

• 🔧 Made from hardened steel

 Punches

There are two main types of punches used in marking:

a) Dot Punch

• 📌 Use: Makes small, light marks to guide marking lines

• 📏 Point Angle: 60°

• 🔹 Used before center punching

b) Centre Punch

• 📌 Use: Makes deep marks to guide the drill bit

• 📏 Point Angle: 90°

• 🛠️ Prevents drill bit from slipping

3. 📐 Divider

• 🔹 Description: Two pointed steel legs joined at the top

• 📌 Use: To mark circles, arcs, or divide lengths

• 🧭 Works like a compass, but without a pencil

• 💡 Used for equal spacing on metal or wood

Calipers

Calipers are used for measuring and marking distances between surfaces or features.

a) Inside Caliper

• 📌 Use: Measures internal diameters (holes, pipes)

• 🧰 Tips face outward

b) Outside Caliper

• 📌 Use: Measures external diameters (rods, wires)

• 🧰 Tips face inward

c) Odd Leg Caliper / Jenny Caliper

• 📌 Use: Marks parallel lines from an edge

• 📐 One leg is pointed; one is curved

Surface Plate

• 🔹 Description: A heavy, flat plate made of cast iron or granite

• 📌 Use: As a reference surface for precision marking

• ⚙️ All height measurements and surface markings are taken on this

📐 Angle Plate

• 🔹 Description: L-shaped plate, made of cast iron

• 📌 Use: To hold a workpiece at 90° angle while marking or drilling

• 🔧 Used with surface plates for vertical marking

📏 Surface Gauge (Marking Stand)

• 🔹 Description: A base with a vertical rod and scriber arm

• 📌 Use: To draw parallel horizontal lines on the surface plate

• 🧰 Helpful in height measurement and layout marking

• marking

🧠 Summary Table

⚠️ Safety Tips

• 👓 Always wear goggles while punching or scribing

• 🧤 Use gloves when handling sharp tools

• 📏 Keep tools rust-free and properly stored

• ❌ Never use a scriber on soft surfaces like wood or plastic

• 🔧 Handle calipers and surface gauges with care to avoid bending

📏 Surface Gauges – Types, Uses, Care & Maintenance

Surface gauges (also called marking stands) are important tools used for accurate marking and layout work, especially on metal surfaces during fitting and fabrication tasks.

🔹 What is a Surface Gauge?

A surface gauge is a tool used to:

• Mark parallel lines

• Transfer measurements

• Check surface flatness and alignment

It works along with a surface plate to achieve high precision in marking.

🛠️ Components of a Surface Gauge

• Base – Heavy, flat base (often cast iron)

• Spindle/Rod – Vertical steel rod attached to the base

• Scriber – Sharp-pointed tool for marking lines

• Adjusting Screws – Used for fine adjustments

• Clamp – Holds scriber in desired position

🧰 Types of Surface Gauges

📌 Uses of Surface Gauge

• ✍️ Marking parallel lines from a reference surface

• 📐 Checking height or dimensions on surface plate

• 🎯 Transferring measurements from one object to another

• ⚙️ Inspecting flatness or straightness of a surface

• 🧱 Holding a dial indicator for inspection work (in advanced models)

🧽 Care and Maintenance of Surface Gauges

To ensure accuracy and long life, follow these care tips:

✅ Daily Use

• 🧼 Wipe the tool before and after use with a clean cloth

• ❌ Do not drop or bang it – it's a precision tool

• 🧲 Keep the base smooth and clean

✅ Storage

• 🗃️ Store in a dry place to avoid rust

• 🔒 Keep in a protective case when not in use

✅ Maintenance

• 🛢️ Apply light oil on spindle and moving parts to avoid corrosion

• 🧰 Check screws and clamps regularly for tightness

• 🧽 Clean scriber point; replace if damaged or dull

⚠️ Safety Tips

• 👓 Wear goggles while marking

• ⚠️ Keep fingers away from the scriber’s sharp point

• 🧲 Be cautious when handling magnetic base models

🧠 Summary Table

💡 Conclusion

A surface gauge is a must-have precision tool for electricians and fitters during layout marking. Proper usage and care will improve accuracy, speed, and professionalism in your work.

🔧 "A precise mark leads to a perfect job!"

Introduction to Sheet Metal Tools

Sheet metal tools are specialized instruments used to measure, cut, bend, and join metal sheets. These tools can be manual or powered, and each serves a specific purpose in sheet metal work. Understanding their functions and proper usage is essential for creating high-quality work.

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🔩 Types of Rivets and Riveted Joints

In sheet metal and electrical fitting work, rivets are used to permanently join two or more metal sheets or components. This method is called riveting.

🔧 What is a Rivet?

A rivet is a mechanical fastener made of soft metal (usually aluminum or mild steel). It has:

• A head (fixed part)

• A shank or body

• After inserting into a hole, the tail end is deformed or hammered to form another head, locking the pieces together.

🛠️ Common Types of Rivets

1. 🟢 Snap Head Rivet

• Also called pan head rivet

• Most commonly used type

• Used for general purpose sheet metal joints

2. 🔵 Flat Head Rivet

• Head is flat and wide

• Used where low clearance is needed

• Good for flush surfaces

3. 🔴 Counter Sunk Head Rivet

• Tapered head fits into a countersunk hole

• Used when a smooth surface is needed

• Ideal for aerodynamic or aesthetic surfaces

4. 🟠 Pop Rivet (Blind Rivet)

• Installed using a pop rivet gun

• Can be used from one side only

• Useful for hollow or difficult-to-reach areas

5. 🟡 Tubular Rivet

• Hollow in the center

• Requires less force to deform

• Used in light sheet metal applications

🔗 Types of Riveted Joints

Riveted joints can be classified by how the rivets are arranged and the number of plates used.

🔹 Based on Plate Arrangement

1. Lap Joint

• Plates overlap each other

• Rivets are placed in overlapping area

• Simple and commonly used

2. Butt Joint

• Plates are placed edge to edge

• A cover plate is added on top or bottom

• Stronger than lap joint

🔸 Based on Rivet Row

1. Single Riveted Joint

• Only one row of rivets

2. Double Riveted Joint

• Two parallel rows of rivets

3. Chain Riveted Joint

• Rivets are in a straight line

4. Zig-Zag Riveted Joint

• Rivets are placed in a zig-zag pattern

• Provides better strength and stress distribution

🧠 Summary Table

⚠️ Safety Tips for Riveting

• 🧤 Wear gloves and goggles while riveting

• 🛠️ Use proper hammer and support tools

• 🔍 Check alignment of holes before riveting

• 🔧 Do not reuse old or deformed rivets

💡 Conclusion

Riveting is a strong and reliable way to join sheet metal parts. Knowing different types of rivets and joints helps you choose the right method for your project and ensures a safe, clean, and durable fit.

🔧 “A strong joint begins with the right rivet!”

🔩 Use of Thread Gauge

A thread gauge is a tool used to check the size and pitch of a screw thread. It helps identify the type of thread on a bolt, screw, or nut.

🧰 What is a Thread Gauge?

A Thread Gauge (also called a screw pitch gauge) is a measuring tool with multiple blades or leaves, each having different thread profiles (like teeth).
These blades are used to match and measure the thread pitch on fasteners.

📌 Main Uses of a Thread Gauge

1. 📏 To Measure Thread Pitch

• The most important use of a thread gauge is to measure thread pitch (the distance between two threads).

• This is useful when you don't know what kind of bolt or screw you're working with.

2. 🔧 To Identify Thread Type

• Helps to identify metric or imperial (inch) threads.

• Allows the correct tool or replacement part to be selected.

3. 🧪 To Check Thread Accuracy

• Used to verify if the threads are worn out or damaged.

• Ensures fitting quality and safety in electrical and mechanical assemblies.

4. 🛠️ To Avoid Wrong Matches

• Prevents using the wrong screw or bolt that may damage the threads or cause accidents.

🔍 How to Use a Thread Gauge?

1. Select the blade that you think matches the thread.

2. Place the blade into the thread of the bolt or screw.

3. If the teeth fit perfectly into the thread grooves — it’s a match!

4. Read the pitch number written on the blade (e.g., 1.25 mm, 20 TPI).

📘 Types of Thread Gauges

🧠 Example:

• If a thread gauge blade marked “1.25 mm” fits a bolt, the thread pitch is 1.25 mm (i.e., distance between threads is 1.25 mm).

• For inch threads, it might say "20 TPI" – meaning 20 threads per inch.

⚠️ Safety & Handling Tips

• 🧤 Handle carefully – the blades are thin and sharp

• 🛠️ Keep the gauge clean and rust-free

• 📦 Store it in its protective case when not in use

• 👀 Use proper lighting while measuring for better accuracy

💡 Conclusion

A Thread Gauge is a small but very useful tool in electrical, mechanical, and fitting work. It helps in correctly identifying threads, which is essential for safe and accurate assembly.

🔧 "Right thread = Tight fit!"

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🪚 Carpenter’s Tools – Description, Care & Maintenance

Electricians often work with wood to install panels, switchboards, or fittings. So it's important to know about basic carpenter’s tools and how to maintain them.

🧰 Description of Common Carpenter’s Tools

1. 🔨 Claw Hammer

• Used for driving and removing nails

• One side is flat for hitting, the other is curved for pulling nails

2. 🪓 Wood Chisel

• Used to cut or carve wood

• Has a sharp beveled edge

• Used with a mallet

3. 🧱 Hand Saw

• Used to cut wooden pieces

• Has a toothed blade for quick and rough cutting

4. 📏 Try Square

• Used to mark and check right angles (90°) on wood

• Essential for accuracy in fitting

5. 📝 Marking Gauge

• Used to draw parallel lines on wood before cutting

• Helps in accurate measurements

6. 🛠️ Mallet

• A wooden hammer used with chisels

• Doesn’t damage tools like metal hammers

7. 🔩 Screwdriver

• Used to insert or remove wood screws

• Available in flat and cross (Phillips) types

8. 🪛 Drill (Hand or Electric)

• Used to make holes in wooden boards or panels

• Comes with various drill bit sizes

🧼 Care & Maintenance of Carpenter’s Tools

🧹 1. Cleaning

• Wipe tools after use with a dry cloth

• Remove sawdust and wood chips

• Use a brush to clean small corners

🔒 2. Storage

• Store tools in a toolbox or on a rack

• Keep sharp tools in protective covers

• Store in a dry place to avoid rust

🧽 3. Lubrication

• Apply light oil to metal parts (e.g., saws, chisels) to prevent rust

• Moving parts (like hand drills) should be oiled regularly

🛠️ 4. Sharpening

• Use sharpening stones for chisels and saws

• Always keep tools sharp for clean and safe work

⚠️ 5. Inspection

• Check for cracks in handles or blades

• Replace damaged tools immediately

• Tighten loose screws or bolts in tools

🧠 Summary Table

💡 Conclusion

Understanding and maintaining carpenter’s tools helps electricians perform wood-based tasks safely and efficiently. Well-kept tools not only last longer but also produce better quality work.

🔧 “Clean tools = Safe hands and smart work!”

✒️ Part 1: Marking Tools – Description & Use

Marking tools help draw lines, angles, arcs, circles, or reference points before cutting or bending.

1. 📏 Steel Rule

• Used for straight line measurements

• Available in different sizes (150 mm, 300 mm, etc.)

• Made of hardened steel

2. ✒️ Scriber

• Sharp-pointed tool for drawing fine lines on sheet metal

• Used with a steel rule or try square

• Helps ensure clean and visible cutting paths

3. 📐 Try Square

• Used to mark or check right angles (90°)

• Helps in maintaining edge alignment

4. ⚖️ Divider

• Used to draw circles or arcs

• Can also divide lengths into equal parts

5. 🖋️ Dot Punch

• Creates light dots or impressions on the sheet

• Used for marking hole positions or cutting start points

6. 🧭 Wing Compass

• Used to draw larger circles or arcs

• Adjustable for repetitive use

✂️ Part 2: Cutting Tools – Description & Use

Cutting tools are used to trim, shape, or cut metal sheets as per markings.

1. ✂️ Straight Snips (Hand Shears)

• Like heavy-duty scissors for sheet metal

• Used for cutting straight lines

• Available in left, right, and straight types

2. 🌀 Curved Snips

• Used to cut curved lines, circles, or irregular shapes

• Ideal for making round switch box holes or curves

3. 🪚 Hack Saw

• Used to cut metal rods or thicker sheets

• Blade is replaceable and comes in different teeth sizes

4. 🔧 Bench Shear (Power Shear – in workshops)

• Heavy-duty cutter for cutting large sheets

• Fixed to the workbench, operated by hand or foot

ry Table

⚠️ Safety Tips

• 👓 Always wear safety goggles

• 🧤 Use gloves to avoid cuts from sharp metal

• 📐 Double-check marking before cutting

• 🧰 Keep tools sharp and clean

• 🛑 Do not use damaged or loose-handled tools