R. Gupta’s®

Hand Book of Mechanical ENGINEERING

by: RPH Editorial Board

Ramesh Publishing House, New Delhi

Published by O.P. Gupta for Ramesh Publishing House Admin. Office 12-H, New Daryaganj Road, Opp. Officers’ Mess, New Delhi-2 23275124, 23275224, 23275124 EMail: [email protected] Website: www.rameshpublishinghouse.com Showroom Balaji Market, Nai Sarak, Delhi-6 23253720, 23282525 4457, Nai Sarak, Delhi-6 23918938 © Strictly reserved with the publisher. No Part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical including photocopying, recording or by any transformation storage and retrieval system without written permission from the Publisher. Indemnification Clause: This book is being sold/distributed subject to the exclusive condition that neither the author nor the publishers, individually or collectively, shall be responsible to indemnify the buyer/ user/ possessor of this book beyond the selling price of this book for any reason under any circumstances. If you do not agree to it, please do not buy/accept/use/possess this book.

Book Code: R-1561 6th Edition: 1706 ISBN: 978-93-5012-337-9

Hand Book of Mechanical ENGINEERING

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A Abrasion Test It is test for hardness of metal by means of a scratch on the smooth surface of the material being tested.

Abrasive Minerals used in different processes like sharpening.

Absorption Dynamometer Absorption dynamometer is used for measuring the work done.

Accelerating Pump A small cylinder and piston fitted to an SI engine carburettor, and connected to the throttle so as to provide a momentarily enriched mixture when the engine is accelerated.

Acceleration It is the rate of change of velocity. For constant velocity, accelaration is zero.

Accelerator Pedal in a motor vehicle which controls the power and speed, by acting on the throttle valve and thereby regulating the mixture of air and petrol entering the engine.

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Hand Book of MECHANICAL ENGINEERING

Accelerometer Instrument used for measuring accelaration is called accelerometer.

Actinometer Instrument for measuring the intensity of the solar rays.

Accumulator An accumulator is an instrument that consists of a heavily weighted tank, which is raised by means of a pump, there by storing up energy to be utilised as required, by its descent.

Accurate Without error within tolerances allowed, precise, correct, confirming exactly to standard.

Acetylene Gas When water is poured on calcium carbide, acetylene gas is resulted. Acetylene flame has high illuminating value.

Activity-on-Note (AON) Diagram The activity-on-node diagram is an alternative method of representing a project network, in which the jobs or activities are denoted by nodes,while the precedence relationships are represented by the arrows. AON diagram does not require any dummy activities.

Adapter Appliance by means of which objects of different sizes will interchange on a spindle or other fitting.

Addendum The radial distance between the pitch circle of a gear wheel and the tip of a tooth.

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Adiabatic process Adiabatic process is one in which there is no flow of heat between a system and its surroundings.

Advance In an internal combustion engine cylinder, when the timing of the ignition is altered to cause the spark in the cylinder to pass at an earlier point, there occurs advance.

Afterburner or Reheater A combustion chamber into which fuel is injected for the purpose of reheating the hot exhaust gases, which cause developing increase thrust.

After-Burning A jet engine functions by sucking in air from the front of the engine and compressing it in a flame tube, into which fuel is then injected and ignited.

Age-hardening In many aluminum alloys after heating-period of 4-5 days it is normalised, so its strength and hardness changes. It is called age-hardening.

Aggregate Mixture of sand and cement to form concrete is called aggregate.

Air Cleaner Filtering device which extracts dust and grit from the air entering any mechanism.

Air-chuck Pneumatically operated chuck used to grip work in a machine tool. A mechanical safety device is generally incorporated to prevent the chuck releasing the work if the air pressure should fail.

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Hand Book of MECHANICAL ENGINEERING

Air Conditioner A device used to control the temperature, humidity, cleanliness and movement of air inside a room or a car.

Air Conditioning Air conditioning is defined as the simultaneous and effec -tive control of the temperature, humidity, air motion and air purity.

Air Cooled Engine An engine that is cooled by the passage of air around the cylinders, not by passage of a liquid through water jackets.

Air Gap The space between the armature and the magnets of an electric motor.

Air Hardening The hardening of high speed steels in a blast of air.

Air Hoist It is a light suspended hoist, operated by compressed air lifting and a piston enclosed in a cylinder.

Air Lift Machine by which water is lifted from deep wells by the aid of compressed air.

Air-lift Pump It is a pump which acts by forcing air from an air-compressor down a small pipe, which is passed down a well or bore-hole from which water is to be raised.

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Air Valve It is used to discharge any air accumulation within pipe line.

Alclad The Increased resistance to corrosion of high strength heat treated alloys, such as those used in aircraft construction by coating of pure aluminium, is called Alclad.

Alignment Chart Graphical means of obtaining quickly the results of numerical formulae. Also, a chart showing means of testing, and the tolerances for machine tools.

All-geared Drive 1. The term “all-geared head” is applied to a lathe headstock so fitted. 2. Applied to the growing practice of operating speeds and feeds of machine tools through nests of gears instead of by belts. The gears are enclosed in boxes, which usually form oil wells.

Allowance It is prescribed difference between the high limit for a shaft and the low limit for a hole in order to provide a certain class of fit.

Alloys and Metals Metals are rarely used in pure form, and the desired properties are normally obtained by suitably alloying different metals. Alloys, unlike most pure metals, do not have a fixed melting point. Also, certain conditions have to be satisfied to make an alloy of two or more materials.

Alpha Iron The phase of iron present in iron or steel below the critical range.

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Hand Book of MECHANICAL ENGINEERING

Alternating Current Current of electricity which is reversed from 25 to 60 times per second, with change of pressure.

Alternator An electrical generator that produces alternating current (flow of current is considered to change in direction with each half cycle).

Aluminium Aluminium is now produced at a comparatively low cost, both in the pure state and alloyed with other metals. It is not found pure in nature, but occurs as an oxide, and a double fluoride of aluminium and sodium. Bauxite is the mineral from which aluminium is extracted.

Aluminium Alloys The value of alloy is greater than that of the pure metal. They are termed “light” or “heavy” according as they contain a large or a small percentage respectively of aluminium.

Aluminium Bronze It is alloy of copper with aluminium, in various and widely differing proportions.

Amalgamation The separation of gold and silver from their ores, by taking advantage of the property which mercury possesses of forming an amalgam with those metals.

Ammeter Instrument designed to show by direct reading the number of amperes of electric current passing in a circuit. Abbreviation of ampere-meter.

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Ammonia Ammonia (NH3) is used as refrigerating agent, the work of the ammonia being to absorb the heat in its passage from the liquid to the gaseous state.

Amorphous Amorphous is a term applied to a non-crystalline metallic surface produced by polishing, when the crystal structure has been completely broken down and the molecules are irregularly distributed, as in the liquid state.

Ampere The unit of electrical current strength. A pressure of one volt will force one ampere through a resistance of one ohm.

Ampere-hour The quantity of electricity delivered by a current of one ampere in one hour.

Amplitude The amplitude of an oscillation is the maximum displacement from mean position.

Angle Bending Machine It is used for dealing with other sections besides angles.

Angle Bevelling Machine It is mechanical instrument in which angles are set between rollers to acute or obtuse sections.

Angle Gauge Angle gauge is an instrument used for testing or finding angles.

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Hand Book of MECHANICAL ENGINEERING

Angular Holo Drilling A tool for form cutting by which holes of square, hexagonal, and other sections are poduced by a chisel-like tool.

Angus Smith’s Process Process employed for protecting water-pipes from corrosion. The pipes are heated to 154° F and immersed in a bath of pitch, to which a little oil is usually added, the temperature of the bath being not less than 98° F.

Angular Momentum Equivalent to moment of momentum.

Anisotropic It is a material whose elastic properties vary in different directions. Same as aeolotropic.

Annealing It includes, among others, full annealing, stress relieving, and process annealing. The general purposes served by annealing are: (i) alteration of ductility and toughness, (ii) induction of softness, (iii) refinement of grain structure, and (iv) removal of gases and stresses.

Annulusa A figure bounded by concentric circles or cylinders (e.g., a washer, ring, sleeve etc.).

Anode The conductor by which a current of electricity enters a liquid or a gas.

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Anodic Treatment The formation of a protective oxide layer on the surface of aluminium and aluminium alloys by suspending the work in a bath of sulphuric acid or chromic acid and passing an electric current from the part, which forms the positive electrode or anode, through the electrolyte to a suitable cathode.

Antenna The group of insulated aerial wires for transmitting or receiving radio communication waves.

Antiknock Quality Abnormal burning or detonation in an SI engine combustion chamber causes a very high rate of energy release, exessive temperature and pressure inside the cylinder and adversely effects its thermal efficiency. Therefore, the characteristics of the fuel used should be such that it resists the tendency to produce detonation and this property is called its antiknock property. The best SI engine fuel wil be that having the highest antiknock property, since this permits the use of higher compression ratios and thus the engine thermal efficiency and the power output can be greatly increased.

Anvil Anvil is the part of a machine which absorbs energy delivered by a sharp force or blow.

Appliance An aid or adjunct to a machine tool, or to a shop operation. Templets, jigs and fixtures are the most striking examples.

Apron It is a covering of timber, stone or metal, to protect a surface from the action of water flowing over it.

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Hand Book of MECHANICAL ENGINEERING

Arbor Press A hand operated machine capable of applying high pressure for the purpose of pressing parts together or removing parts.

Arc Lamp An electric lamp in which, a gap being made in an electric circuit between two carbon rods.

Archimedes’ Principle The principle discovered by Archimedes that, when a body is weighed in a fluid, it appears to lose weight by an amount equal to the weight of the fluid it displaces.

Armature The revolving member in a dynamo, comprising an iron case on a shaft, carrying on its outer surface copper conductors which cut through the magnetic lines of the field, and receive by induction the currents generated in the field magnets.

Armoured Hoses These are rubber or other hoses covered with spirally wound steel wire to protect them from cuts, abrasions or any other kind of damages.

Aspiration Effect For a mould made of a permeable material (e.g., sand), care should be taken to ensure that the pressure anywhere in the liquid metal stream does not fall below the atmospheric pressure. Otherwise, the gases originating from baking of the organic compounds in the mould will enter the molten metal stream, producing porous castings. This is known as the aspiration effect.

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Assembling It means the joining of parts that comprise a piece of mechanism, without any change or manual fitting. This is possible when all parts are fully interchangeable and made to precision.

Assembly Drawing A drawing which shows the relative arrangement of various parts when they are fitted together to form an assembly. The majority of drawings used in an engineering workshop refer to the manufacture of one part only of an assembly, e.g., for the manufacture of a lathe chuck, one drawing will show details for the body, another for the jaws, another for the scrolls, and so on. The assembly drawing will show all these parts gatherd together in their correct position to form the chuck.

Atkinson Cycle It consists of two adiabatics, a constant volume heat addition, and a costant pressure heat rejection process. This cycle is used by constant volume type gas turbines.

Atomic Hydrogen Welding It is a method of welding in which a single-phase, alternating current arc is struck between the tips of two tungsten electrodes which project from tubular nozzles through which hydrogen or cracked ammonia gas is fed.

Atomic Energy When high speed atomic particles are bombarded on atom. It splits, the amount of energy radiated is called atomic energy.

Atomiser Atomiser is a nozzle by means of which liquid fuel is reduced to a fine spray which readily ignites.