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Answer any three of the following: (i) Identify three safety features incorporated in the design of a centre lathe - Leaving Cert Engineering - Question 7 - 2013
Question 7
Answer any three of the following: (i) Identify three safety features incorporated in the design of a centre lathe. (ii) Describe the purpose of a plug gauge. (ii... show full transcript
Worked Solution & Example Answer:Answer any three of the following: (i) Identify three safety features incorporated in the design of a centre lathe - Leaving Cert Engineering - Question 7 - 2013
Step 1
Identify three safety features incorporated in the design of a centre lathe.
Answer
- Guarding: Moving parts must be guarded to prevent accidental contact.
- Prominent Controls: Stopping controls are made accessible to ensure quick response in emergencies.
- Vibration Reduction: A robust design minimizes vibration, enhancing operator safety.
Step 2
Step 3
Distinguish between any two types of chip formed when machining.
Answer
- Continuous Chip: This type is smooth and long, typically formed during machining of ductile materials at higher speeds, which is desirable as it helps in better surface finish.
- Discontinuous Chip: This chip breaks up into smaller segments, usually occurring with brittle materials or during interrupted cutting, leading to increased tool wear.
Step 4
Outline three methods of machining flat surfaces on metals.
Answer
- Milling: A rotary cutter removes material to produce a flat surface.
- Surface Grinding: This process uses a grinding wheel to achieve a flat finish.
- Facing on the Lathe: Material is cut with the lathe's cutting tools to create a flat surface.
Step 5
Identify one advantage and one disadvantage of using carbide tipped cutting tools when machining.
Answer
Advantage: Carbide tools maintain sharpness at high temperatures, improving cutting performance.
Disadvantage: They are more brittle and expensive compared to other materials, making them prone to breaking under shock loads.
Step 6
Outline the main features of a surface grinding machine.
Answer
A surface grinding machine consists of a rotating grinding wheel, a workpiece held on a magnetic chuck, and a table that moves the workpiece in a straight line. The grinding wheel continuously removes material, providing a high degree of flatness and finish.
Step 7
Describe three hazards associated with using a bench grinder.
Answer
- Flying Particles: The grinding process can emit small metal particles at high speeds, posing risks of eye injury.
- Improper Use of Grinding Wheels: If grinding wheels are not properly mounted, they can break during operation, leading to injury.
- Clothing Risks: Loose clothing can get caught in the grinder, causing potential harm to the operator.
Step 8
Describe, with the aid of suitable diagrams, the differences between gang milling and straddle milling.
Answer
In gang milling, multiple milling cutters are mounted side by side on the arbour, allowing the machining of various surfaces in one pass. On the other hand, straddle milling involves two or more cutters that are separated by spacers, which allows for the creation of two parallel surfaces on a workpiece. Diagrams should show the arrangement of tools for clearer understanding.