Workshop Tools and Operations: Vices, Lathe Facing, Grinding, Inspection
Types of Vices (6 Marks)
A vice is a work-holding device used to hold a workpiece firmly during various workshop operations such as filing, sawing, drilling, and fitting.
The different types of vices are:
- Bench Vice
Fixed to a workbench and commonly used in fitting shops for general work-holding operations. - Hand Vice
Small and portable vice used to hold thin or small workpieces. - Machine Vice
Used on drilling and milling machines to hold the workpiece accurately during machining. - Pipe Vice
Specially designed to hold round objects like pipes and tubes. - Pin Vice
Used to hold very small tools such as drill bits, pins, and wires. - Leg Vice (Blacksmith’s Vice)
Heavy-duty vice used in blacksmith shops; has a leg that transfers load to the ground.
Conclusion: Different types of vices are used depending on the size, shape, and nature of the workpiece to ensure safety and accuracy during operations.
Types of Vices (6 Marks)
A vice is a work-holding device used to hold a workpiece firmly during various workshop operations such as filing, sawing, drilling, and fitting.
The different types of vices are:
- Bench Vice
Fixed to a workbench and commonly used in fitting shops for general work-holding operations. - Hand Vice
Small and portable vice used to hold thin or small workpieces. - Machine Vice
Used on drilling and milling machines to hold the workpiece accurately during machining. - Pipe Vice
Specially designed to hold round objects like pipes and tubes. - Pin Vice
Used to hold very small tools such as drill bits, pins, and wires. - Leg Vice (Blacksmith’s Vice)
Heavy-duty vice used in blacksmith shops; has a leg that transfers load to the ground.
Conclusion: Different types of vices are used depending on the size, shape, and nature of the workpiece to ensure safety and accuracy during operations.
Types of Vices (6 Marks)
A vice is a work-holding device used to hold a workpiece firmly during various workshop operations such as filing, sawing, drilling, and fitting.
The different types of vices are:
- Bench Vice
Fixed to a workbench and commonly used in fitting shops for general work-holding operations. - Hand Vice
Small and portable vice used to hold thin or small workpieces. - Machine Vice
Used on drilling and milling machines to hold the workpiece accurately during machining. - Pipe Vice
Specially designed to hold round objects like pipes and tubes. - Pin Vice
Used to hold very small tools such as drill bits, pins, and wires. - Leg Vice (Blacksmith’s Vice)
Heavy-duty vice used in blacksmith shops; has a leg that transfers load to the ground.
Conclusion: Different types of vices are used depending on the size, shape, and nature of the workpiece to ensure safety and accuracy during operations.
Lathe Machine – Facing Operation (6 Marks)
Facing is a basic and important operation performed on a lathe machine to produce a flat and smooth surface at the end of a cylindrical workpiece.
Definition
Facing is the process of removing metal from the end of the workpiece, perpendicular to the axis of rotation, to obtain the required length and a smooth finish.
Working Principle
In the facing operation, the workpiece is held in a chuck and rotated at a suitable speed. The cutting tool is fed radially (cross-feed) from the outer diameter towards the center of the workpiece. Material is removed in the form of chips until a flat surface is obtained.
Steps in Facing Operation
- Workpiece is clamped in the chuck.
- Facing tool is fixed in the tool post.
- Proper speed and feed are selected.
- Tool is fed across the face of the workpiece.
- Cutting continues until a flat surface is achieved.
- Machine is stopped and surface is checked.
Applications
- Squaring the ends of shafts
- Preparing work for further operations
- Achieving accurate length of workpiece
Advantages
- Produces flat and smooth surface
- Improves dimensional accuracy
Conclusion: Facing operation is essential in lathe machining to ensure proper alignment, length accuracy, and surface finish of components.
Hand Grinding Machine (6 Marks)
A hand grinding machine is a portable power tool used for grinding, cutting, polishing, and surface finishing operations.
Construction
A hand grinding machine consists of the following parts:
- Electric motor: Provides power for rotation.
- Grinding wheel / disc: Performs grinding or cutting.
- Spindle: Holds the grinding wheel.
- Body casing: Houses the motor and provides grip.
- Switch: Used to start and stop the machine.
- Guard: Protects the operator from sparks and fragments.
Working Principle
When the machine is switched on, the electric motor rotates the grinding wheel at high speed. The rotating wheel removes material from the workpiece by abrasion when brought into contact with it.
Applications
- Grinding and smoothing metal surfaces
- Removing burrs and sharp edges
- Cutting metal rods and pipes
- Polishing and finishing work
Advantages
- Portable and easy to handle
- Suitable for on-site work
- Saves time and effort
Safety Precautions
- Wear safety goggles and gloves
- Ensure proper wheel mounting
- Do not apply excessive pressure
Conclusion: Hand grinding machines are widely used in workshops and fabrication sites due to their flexibility, portability, and efficiency.
Surface Plate (6 Marks)
A surface plate is a precision flat reference surface used in workshops and metrology for measurement, marking, and inspection work.
Definition
A surface plate is a perfectly flat, smooth, and level plate used as a datum for layout and inspection of components.
Construction
Surface plates are made from:
- Cast iron (traditional type)
- Granite (most commonly used due to stability and wear resistance)
They are supported on three-point supports to maintain flatness.
Working / Use
Workpieces are placed on the surface plate, and measuring instruments like a height gauge, dial indicator, and try square are used to check dimensions and accuracy.
Applications
- Marking layout lines
- Checking flatness and straightness
- Inspection of machined parts
- Calibration of measuring instruments
Advantages
- High degree of accuracy
- Does not wear easily (granite)
- Provides a reliable reference surface
Care and Maintenance
- Keep the surface clean and dry
- Avoid heavy impacts
- Cover when not in use
Conclusion: Surface plates are essential tools in precision engineering for accurate measurement and inspection work.
Scriber (6 Marks)
A scriber is a marking tool used in fitting and machine shops to draw fine and accurate lines on metal surfaces.
Definition
A scriber is a hardened steel tool with a sharp pointed end used for marking layout lines on workpieces before machining.
Construction
- Made of hardened and tempered high-carbon steel
- One or both ends are sharply pointed
- Sometimes one end is bent for reaching difficult areas
- Handle may be knurled for better grip
Working / Use
The scriber is drawn over the metal surface using a steel rule, try square, or surface plate as a guide to produce precise lines.
Types of Scriber
- Straight scriber
- Bent or hooked scriber
- Double-ended scriber
Applications
- Marking layout lines on metal
- Preparing work for cutting or drilling
- Accurate positioning of holes and slots
Advantages
- Produces thin, clear lines
- Simple and durable
- High accuracy in marking
Conclusion: A scriber is an essential marking tool in workshops, ensuring precision and accuracy in layout work before machining operations.