College

**L5 SEPT 2023 JANUARY OPENER EXAM**

1. Describe the following parts of a lathe machine:
a) Headstock
b) Bed
c) Tailstock
d) Carriage

2. Use sketches to describe the following lathe machine operations:
a) Turning
b) Taper turning
c) Eccentric turning
d) Facing
e) Threading
*(20 marks)*

3. Describe parts of a lathe apron.
*(10 marks)*

4. Explain how five lathe machines can be specified.
*(10 marks)*

5. Explain the following types of lathe machines:
a) Centre/engine lathe
b) Bench lathe
c) Automatic lathe
d) Computer-controlled lathe machine
*(12 marks)*

6. Explain six work-holding devices in lathe work.
*(18 marks)*

7. Mention five types of lathe centers.
*(5 marks)*

Answer :

Final answer:

This comprehensive overview of lathe machines covers key components, operations, specific types, and workholding methods. The main parts include the headstock, bed, tailstock, and carriage, while operations such as turning and threading are essential in machining. Additionally, different types of lathes, including CNC and automatic lathes, offer various functionalities for different applications.


Explanation:

1. Parts of a Lathe Machine

A lathe machine consists of several key components:

  1. Head Stock: This is located at the left end of the lathe and houses the main motor and the driving mechanism. It holds the spindle, which rotates the workpiece.
  2. Bed: The bed acts as the main frame of the lathe and supports all other components. It provides stability and alignment for machining operations.
  3. Tail Stock: Positioned opposite the headstock, the tailstock is adjustable and is used to support the free end of the workpiece. It can also accommodate drilling operations.
  4. Carriage: The carriage moves along the bed and is responsible for holding the cutting tool. It is equipped with controls for adjusting the position of the tool.

2. Lathe Machine Operations

Various operations can be performed on a lathe machine:

  1. Turning: This involves rotating the workpiece against a cutting tool to create cylindrical shapes.
  2. Taper Turning: This operation creates a conical shape by gradually adjusting the angle of the tool as the workpiece rotates.
  3. Eccentric Turning: It is used to create non-uniform shapes by offsetting the workpiece from the spindle axis.
  4. Facing: This operation flattens the end surface of the workpiece by moving a cutting tool laterally.
  5. Threading: In threading, a special cutting tool is used to form threads on the workpiece, allowing for screw-type mechanisms.

3. Parts of a Lathe Apron

The apron is attached to the carriage and contains several components such as:

  • Feedscrew
  • Clutch mechanism
  • Controls for tool travel
  • Handwheels to manually adjust the tool position
  • Gear mechanisms to change the feed rate

4. Specification of Lathe Machines

Lathe machines can be specified based on:

  1. Type of lathe (e.g., center lathe, CNC lathe)
  2. Size of workpiece the machine can accommodate
  3. Speed and power of the motor
  4. Type of material it can machine (metal, plastic, etc.)
  5. Precision level required for the applications

5. Types of Lathe Machines

Common types of lathe machines include:

  1. Centre/Engine Lathe: A versatile lathe used for general-purpose machining.
  2. Bench Lathe: Smaller and suitable for lightweight materials and hobbyist work.
  3. Automatic Lathe: Designed for high productivity, automatically performing some or all operations.
  4. Computer Controlled Lathe Machine: Uses CNC technology for precision and control in the machining process.

6. Work Holding Devices in Lathe Work

Devices used for secure workholding include:

  • Chucks
  • Vices
  • Collets
  • Faceplates
  • Mandrels
  • Fixture plates

7. Types of Lathe Centres

Common types of lathe centres include:

  1. Live Centre
  2. Dead Centre
  3. Combination Centre
  4. Automatic Centre
  5. Point Centre

Learn more about Lathe machines here:

https://brainly.com/question/30590667


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