Ques.21. Which of the following is used to hold a round metal rod or pipe for performing drilling operations?
V-block with clamp
Calliper
Divider
Try square
Answer.1. V-block with clamp
Explanation
V-blocks are precision-made blocks with special slots made to anchor clamps that hold workplaces. The V-slot of the block is designed to hold round workplaces. The V-block and clamp set are usually used to hold and drill round.
Ques.22. Which of the following is NOT a cause for flaking type failure in bearings?
Excessive slippage of the rolling elements
Improper lubrication
Improper precision in the shaft or housing
Insufficient clearance
Answer.1. Excessive slippage of the rolling elements
Flaking or surface fatigue: Flaking occurs when small pieces of bearing material are split off from the smooth surface of the raceway or the rolling elements. This causes regions with a rough and coarse texture.
Most bearing damage can be classified into two damage categories: preoperational and operational. Preoperational damage occurs before or during bearing installation, while operational damage occurs while the bearing is in operation.
Causes of preoperational damage:
Bearing quality and application
Storage and handling
Incorrect shaft and housing fits
Defective bearing seats on shafts and in housings
Static misalignment
Faulty mounting practices
Passage of electric current through the bearing (excessive voltage)
Transportation, handling, and storage
Causes of operational damage:
Material fatigue
Ineffective lubrication
Ineffective sealing
Vibration (false brinelling)
Operational misalignment
Bearing internal Clearance
Passage of electric current through the bearing (current leakage)
Ques.23. Fittings are used in the pipe system:
To measure the length of the pipe
To connect the pipes
To measure the flow rate of the fluid flow in the pipe
To measure the diameter of the pipe
Answer.2. To connect the pipes
Explanation:-
The Fitting system type is assigned to connectors used in Pipe Fitting Families, such as tees and elbows. These types of connectors will inherit the flow, direction, and system characteristics of the components they connect to.
Ques.24. Frosting is:
Making multiple holes on the surface by a drilling machine
A joining operation
A decolouration made by scraping
A gas cutting operation
Answer.3. A decolouration made by scraping
Explanation
The frosting is decolouration made by scraping. Frosting occurs when only the metal irregularities weld and break.
Frosting
The frosting is a process in which scraped metal surface is decorated with the use of hand scraper.
Frosting can also be called as flaking or flowering.
When a patterned finish is formed on a polished or scraped flat surface
Why frosting is used
The frosting used as a way of increasing oil retention on scraped or polished surfaces.
This is important with machine parts in order to keep them lubricated and moving smoothly instead of sticky and jerky movement.
Without the frosting, the oil would runway, leaving just the two metal surfaces in contact with each other, which is likely to cause seizure of the machine.
Ques.25. What is the specific gravity of tungsten?
There are different types of drilling machine such as
Portable drilling machine
Bench Drilling Machine
Upright Drilling Machine
Radial Drilling Machine
Gang Drilling Machine
Turrent Drilling Machine
Hand Drilling machine
Push type is not a drilling machine
Ques.27. Which of the following is the most appropriate percentage range of carbon content in cast iron used for commercial purposes?
7-10%
10-14%
14-18%
2-4%
Answer.4. 2-4%
Explanation:-
Cast iron is an alloy primarily composed of iron, carbon, and silicon. It has a relatively high carbon content (2-4%), compared to wrought iron and steel.
Ques.28. The ability of a material to be drawn into wires without fracture is termed as
Ardenability
Elasticity
Foldability
Ductility
Answer.4. Ductility
Explanation:-
Ductility is the ability of the material to be drawn into wires without fracture is called ductility. It is committed by pulling force.
It is measured in terms of
Percentage of area reduced
Percentage in elongation occurred.
Ques.29. What should be done if odd noise or vibrations are developed during the operation of a lathe?
Remove the limit switch immediately.
Remove the chips with a wire brush immediately.
Stop the machine immediately and it should not be operated till the fault is cleared.
Run the machine in reversing the condition.
Answer.3.Stop the machine immediately and it should not be operated till the fault is cleared
Explanation:-
If any odd sounding noise or vibration develops during lathe operation, stop the machine immediately. If you cannot locate the trouble, get help from your instructor. Do not operate the machine until the trouble has been corrected.
Ques.30. Kerf is _____
Angle gauge
Another name for shearing torch
Another name for welding torch
Uniform slot cut by high pressure of oxygen
Answer.4. Uniform slot cut by the high pressure of oxygen
Explanation:-
When a piece is cut by an (Oxygen cutting) OC or (Arc cutting) AC process, the narrow width of metal is progressively removed. The width of the cut is called the kerf. Control of the kerf is important in cutting operations where dimensional accuracy of the part and squareness of the cut edges are significant factors in quality control. A uniform wide slot, called kerf, is cut by the high-pressure stream of oxygen.
As material thickness increases, oxygen flow rates must usually be increased. Cutting tips with larger cutting oxygen ports are required to handle the higher flow rates. Consequently, the width of the kerf increases as the material thickness being cut increases.
