Trade Theory/2nd Year Fitter Nsqf Level 5 2018/20 Batch

A feeler gauge is a tool that is used to measure the clearance between two mating parts. It consists of a set of thin metal blades of varying thicknesses. These blades can be inserted between the two parts to determine the gap or clearance between them. This is important in various applications, such as in automotive engines, where proper clearance between components is crucial for smooth operation and to prevent damage. By using a feeler gauge, technicians can ensure that the correct clearance is maintained, leading to optimal performance and longevity of the parts.

Petroleum jelly is used to protect slip gauges from rust because it forms a protective barrier on the surface, preventing moisture and air from reaching the metal. This helps to prevent oxidation and corrosion, which can lead to rusting. Petroleum jelly is also resistant to water and has a low evaporation rate, making it an effective choice for long-term protection against rust.

Wringing is the correct answer because it refers to the process of using a grade slip gauge for precision tool room applications. Wringing involves the tight connection between two surfaces, where the slip gauge is wrung onto the reference surface to ensure accurate measurements. This method is commonly used in precision tool rooms where precision and accuracy are crucial.

Stabilized chromium steel is used to make sine bars. Sine bars are precision measuring tools used in engineering and machining to measure angles accurately. Stabilized chromium steel is a high-quality material that offers excellent stability, durability, and resistance to wear and corrosion. It is known for its high strength and dimensional stability, making it suitable for precise measurements. The use of stabilized chromium steel ensures that the sine bar maintains its accuracy and reliability over time, making it an ideal choice for this application.

Grade I slip gauge is used for precision tool room applications because it has the highest accuracy and precision among the options given. Grade I slip gauge has extremely tight tolerances and is manufactured with the highest level of precision. It is commonly used in industries where precision measurements are crucial, such as tool rooms, calibration laboratories, and manufacturing facilities.

The hypotenuse of a triangle formed while checking with a sine bar is the sine bar length. The sine bar is a precision measuring tool used to measure angles accurately. It consists of a long bar with two cylindrical rollers at the ends. By placing the sine bar on a surface plate and using slip gauges to raise one end, a right triangle is formed. The hypotenuse of this triangle is the sine bar length, which is used to calculate the angle being measured.

The centre line of contact roller and datum surface of the sine bar are parallel to each other. This means that they lie on the same plane and do not intersect. This parallel alignment is important in order to ensure accurate measurements and proper functioning of the sine bar.

Cladding is the method of applying a layer of metal onto a base metal through rolling or drawing. This process creates a protective coating that enhances the durability and corrosion resistance of the base metal. Hot dipping involves immersing the base metal into a molten bath of metal, while enameling is the process of applying a layer of glass or ceramic onto the base metal. Spraying, on the other hand, refers to the method of applying a thin layer of metal onto the base metal using a spray gun.

Liquid carburizing is a method of surface hardening that is done in a heated salt bath. In this process, the metal part is immersed in a bath of molten salt that contains carbon-rich compounds. The high temperature of the bath allows carbon atoms to diffuse into the surface of the metal, creating a hardened outer layer. This method is commonly used for steel parts that require increased hardness and wear resistance. Nitriding, carburizing, and gas carburizing are also methods of surface hardening, but they do not involve the use of a heated salt bath.

Normalizing is a heat treatment process used to refine the structure of a metal. During normalizing, the metal is heated to a specific temperature and then cooled in still air. This process helps to eliminate internal stresses, improve the uniformity of the metal's microstructure, and enhance its mechanical properties. By refining the structure, normalizing can improve the metal's strength, toughness, and overall performance.

A thread ring gauge is used to check the accuracy of an external thread. This gauge has a ring-like shape with internal threads that are designed to match the external threads of the part being inspected. The part is screwed into the ring gauge, and if the threads fit perfectly without any gaps or excessive tightness, then the thread is considered accurate. This gauge is commonly used in industries such as manufacturing and engineering to ensure the quality and precision of threaded components.

A ring gauge is used to check the diameter of a hole. It is a cylindrical tool with a precisely calibrated diameter that is used to ensure that the hole being measured is within the specified tolerance range. By inserting the ring gauge into the hole, one can determine if the diameter of the hole matches the required specifications. This is important in various industries, such as manufacturing and engineering, where accurate measurements are crucial for the proper functioning of components and products.

The length of a sine bar is specified by the distance between the centers of the rollers. This distance determines the effective length of the sine bar and is crucial for accurate measurements and calculations. The distance between the centers of the rollers directly affects the sine bar's ability to accurately establish angles and perform various trigonometric functions. Therefore, it is essential to specify this distance correctly when using a sine bar for precision measurements and machining operations.

When normalizing a component, it needs to be cooled in order to achieve the desired microstructure and properties. Cooling in still air at room temperature is a common method used for normalizing. This process allows for controlled cooling, where the component is left to cool naturally in the surrounding air. This gradual cooling helps to refine the grain structure and relieve internal stresses, resulting in improved mechanical properties. Water or oil cooling methods are not typically used for normalizing, as they provide more rapid cooling rates that may lead to different microstructural changes.

The correct answer is "Minimum number of block". When building up a slip gauge for a particular dimension, it is important to use the minimum number of blocks necessary to achieve the desired accuracy. Using fewer blocks reduces the chances of errors and increases the precision of the measurement. By minimizing the number of blocks, the overall accuracy of the slip gauge is improved.

Ferrite is a structure of steel that contains 0% carbon. It is a pure form of iron and is the softest and weakest among the different structures of steel. Ferrite has a body-centered cubic (BCC) crystal structure and is stable at low temperatures. It is commonly found in low carbon steels and is responsible for their good ductility and toughness.

The correct answer is annealing. Annealing is the process of heating steel to its critical temperature and then cooling it slowly in a furnace. This process helps to reduce the hardness and increase the ductility of the steel, making it easier to work with and less prone to cracking or breaking. Hardening, on the other hand, involves heating the steel to its critical temperature and then rapidly cooling it, which increases its hardness and strength. Quenching and tempering are also heat treatment processes, but they involve different cooling techniques and have different effects on the steel's properties.

The temperature at which the change of structure to austenite starts in the heat treatment process is known as the lower critical temperature.

Grade 0 slip gauges are used for inspection purposes because they have a high level of accuracy and precision. These gauges are manufactured to very tight tolerances and are used to calibrate and check the accuracy of other measuring instruments. Grade 0 slip gauges are typically made from high-quality steel and have a surface finish that allows for accurate measurements. They are commonly used in industries such as manufacturing, engineering, and metrology where precise measurements are crucial.

Quenching is the process of rapidly cooling heated steel by immersing it in a liquid, usually oil or water. This rapid cooling creates a hardened structure in the steel, enhancing its cutting ability and wear resistance. During the quenching process, the steel undergoes a phase transformation, resulting in a hardened microstructure. This process is commonly used in the manufacturing of tools and components that require high strength and durability.