Mechanical Engineers Data Handbook Episode 13 ppsx

290 MECHANICAL ENGINEER’S DATA HANDBOOK 8.. 294 E== Uniform strength bolts Square neck Ribbed neck Serrated neck Coach bolts cardage bolts Hexagon socket head s ~ e w Hexagon suAet

290 MECHANICAL ENGINEER’S DATA HANDBOOK

8 I .2 Abbreviations for technical terms

Bottom dead centre

Brake mean effective pressure

Intermediate frequency Internal combustion Internal combustion engine Kinetic energy

Lower calorific value Low pressure Low tension Low voltage Magnetomotive force Maximum

Mean effective pressure Melting point

Minimum Moment Numerical control Pitch circle diameter Potential difference Potential energy Pressure Proof stress Radian Radio frequency Radius

Relative density Relative humidity Root mean square Specific

Specific gravity Standard temperature and pressure Strain energy

Temperature Tensile strength Thermocouple Top dead centre Ultraviolet Ultra-high frequency Very high frequency Yield stress

h.t

h.v

h.p

i.m.e.p i.r

i.f

i.c., IC i.c.e

k.e

I.C.V., LCV 1.p

v.h.f

U.V

ys., YS

GENERAL DATA 29 1

0 I .3 Abbreviations for units

revolution per

minute kilogramme gramme tonne

( = 1 Mg)

seimen atomic mass unit Dascal

N bar

mb atm

mm Hg

P

s, St

J kW-h

eV cal

mole watt decibel kelvin centigrade coulomb ampere volt ohm farad henry weber tesla

psi =pounds per square inch

Tsi = tons per square inch atm = atmosphere

1 =litre cc=cubic centimetre gal =gallon

Ib =pound Ibm =pound mass Ibf = pound force

k, kip = kilopound

t, T=ton tnf, tonf = ton force mph =miles per hour fpm = feet per minute

kt = knot (nautical mile per hour) gpm =gallons per minute cfs =cubic feet per second cfm =cubic feet per minute

N =newton

s, sec = second min = minute

h = hour

hp = horsepower

kW = kilowatt Btu = British thermal unit

J =joule

Length

1 in = 25.4 mm = 0.0254 m

lft=305mm=0.305m

292 MECHANICAL ENGINEER'S DATA HANDBOOK

1 ton (US or 'short')=2000Ibm=907.2kg

1 ton (UK or 'long')=2240Ibm= 1016kg

1 tonne (metric ton) = lo00 kg

Bolts are used for fastening machine parts together

often in conjunction with nuts and washers to form

non-permanent connections The bolt head is usually

hexagonal, but may be square or round The ‘shank’

may be screwed for part or the whole of its length, in

the latter case it is sometimes called a ‘screw’ or

‘machine screw’

Most bolts are made of low or medium carbon steel

by forging or machining with threads cut or rolled Forged bolts are called ‘black’ and machined bolts

‘bright’ They are also made in high tensile, alloy and stainless steels as well as non-ferrous metals and alloys, and plastics Bolts may be plated or galvanized to prevent corrosion

In the UK, metric threads (ISOM) have largely

replaced BSW and BSF threads For small sizes British Association (BA) threads are used In the USA, the most used threads are ‘unified fine’ (UNF) and ‘unified coarse’ (UNC)

Hexagonal head boll

stud (Stud bok)

294

E==

Uniform strength bolts

Square neck Ribbed neck Serrated neck

Coach bolts (cardage bolts)

Hexagon socket head s ~ e w

Hexagon suAet head screw-application

ul

Hexagon socket wrench (Allen key)

@ Socket button +head -screw

Socket muntersurk head screw

Socket shoulder head screw

MECHANICAL ENGINEER'S DATA HANDBOOK

-1

Eye bolt

indented foundation bon

GENERAL DATA 295

Screws

The term 'screw' is applied to a wide range of threaded

fasteners used with metal, wood, plastin, etc Screws

have a variety of types of head and are made in many

materials (steel, brass, nylon, etc.), some are plated

Small screws usually have %A threads and special

threads are used for wood and self-tapping screws

U'dEiPB

Cheese Rolnd Camtem~nkFWstw I

-h e e d p head M ( W ) head (Ormi8d

head

skttedheadmaoMnescter*s

M

0.2.2 Nuts a d washers

Nuts are usually hexagonal, but may be square or round Steel hexagon nuts may be 'black' or 'bright' and have one or both faces chamfered Washers are used to distribute load and prevent damage to a surface They are mostly of steel, but brass, copper, aluminium, fibre, leather and plastin are used

A wide variety of lock washers and locking devices are available, including adhesives such as 'Loctite'

296 MECHANICAL ENGINEER’S DATA HANDBOOK

Wing nut

Barrel nut Welded type barrel nut

Elastic stop nut (NYLOC nut)

GENERAL DATA 297

Helical spring lock washer

Two-coil spnng lodc washer

-i-

internally serrated lock washer (tooth kdc washer)

Externally serrated lo& washer: (a) fiat and (b) for countersunk hole

Tab washer

Rivets

Rivets are used to make permanent joints between two

or more plates Steel rivets may be closed when red hot; rivets of softer metals such as aluminium and copper may be closed cold There are a number of types of riveted joint configurations for plates, two of which are shown in the figure

Countersunk Round head

298 MECHANICAL ENGINEER’S DATA HANDBOOK

tight fit Split pins are used mainly for locking nuts

Cotter pins are used to connect rods in tension and fits into mating slots

Explosive rivet

Riveted lap joint

Double riveted bun pint with two straps

Pins

Dowel pins

Dowel pin fitted

The term ‘pin’ refers to a large number of components

used for fixing, locating and load carrying Dowel pins

are used to locate accurately one part relative to

another Taper pins fit into taper holes and are often

used for light shaft couplings A grooved pin has

grooves with raised edges to give a tight fit in a hole -* @ - \ ~

The roll pin is a spring steel tube which closes to give a Split pin (cotter pin)

GENERAL D A T A 299

8.2.4 I S 0 metric nut arad bolt sizes

IS0 metric precision hexagon nuts and bolts (all quantities) (in mm)

6.82 3.3 11.3 4.2 15.8 5 30.0 6.8

48 8.5 70.5 10.2

pr =pitch (fine series)

pE =pitch (coarse series)

f = width across flats

c = width across corners

h=height of head

Lmin =minimum length of thread

t , =thickness of normal nut

t , = thickness of thin nut Ab=area at bottom of thread

D, = tapping drill diameter for coarse thread

300 MECHANICAL ENGINEER’S DATA HANDBOOK

8.2.5 Clearance holes for bolts

Clearance holes for metric bolts

diameter Pitch diameter of thread

4.80 18.10 4.22 13.99 3.73 10.93 3.22 8.14

2.49 4.87

1.92 2.89 1.68 2.22

1.28 1.29 1.13 1 OO

GENERAL DATA 301

Coarse series (UNC) Fine series ( U N F ) Nominal

diameter No threads of threads No threads of threads

1.2500

1 .5000

1.524 1.854 2.184 2.5 15 2.845 3.175 3.505 4.166 4.826 5.486 6.350 7.938 9.525 11.11 12.70 14.29 15.88 19.05 22.23 25.40

3 1.75 38.10

0.480 0.625 1.024 1.260

0.974 1.529 2.187 2.910 3.652 4.619 5.639 8.290 11.29 14.58 21.03 33.81 52.19 70.32 95.87 121.9 154.8 226.5 309.7 403.2 660.6 812.9

8.2.0 Pipe threads

BSP pipe threads (BS 2779: 1973) - Whitworth thread form

Nominal size Threads per Pitch Major diameter Minor diameter

7.723 9.728 13.157 16.662 20.955 22.91 1 26.441 30.201 33.249 37.897 41.910

6.561 8.566

1 1.445 14.950 18.631 20.587 24.1 17 27.877 30.291 34.939 38.952

302 MECHANICAL ENGINEER’S DATA HANDBOOK BSP pipe threads (BS 2779: 1973) - Whitwortb thread form (continued)

47.803 53.746 59.614 65.710 75.189 81.534 87.884 100.330 113.030 125.73 138.43 151.13 163.83

44.845 50.788 56.656 62.752 72.226 78.576 84.926 97.372 110.072 122.772 135.472 148.172 160.372

Dimensions (mm)

3 3.5

4

5

5 5.5

6

7 7.5

0.16 0.16 0.16 0.25 0.25 0.25 0.40 0.40 0.40 0.40 0.40 0.60 0.60 0.60 0.60 0.60

1 00

1 00

1 OO

1 OO 1.60 1.60 1.60 2.50 2.50 2.50

0.08 0.08 0.08 0.16 0.16 0.16 0.25 0.25 0.25 0.25 0.25 0.40 0.40 0.40 0.40 0.40 0.70 0.70 0.70 0.70 1.20 1.20 1.20 2.00 2.00 2.00

304 MECHANICAL ENGINEER'S DATA HANDBOOK

8.3 I

hollow steel sections

Circular, square and rectangular

M = mass per unit length

A =cross-sectional area

1, =second moment of area about axis XX

I , =second moment of area about axis YY

Circular hollow steel sections (BS 4848: Part 2)

D o t M A 1, Do t M A 1,

(mm) (mm) (kgm-') (an2) (cm4) (mm) (mm) (kgm-') (cm2) (cm') 21.3

1.70 3.09 3.60

6.46 7.62 8.99 11.60 13.8 16.2 23.5 28.2

48.8 59.1 70.9 79.2 96.3

8 .o

10.0 5.0 6.3 8.0 10.0 5.4 6.3

8 .o

10.0 12.5 16.0 6.3

8 .o

10.0 12.5 16.0 20.0

16.6 20.7 26.0 32.0 20.1 25.2 31.6 39.0 25.1 29.1 36.6 45.3 55.9 70.1 33.1 41.6 51.6 63.7 80.1 98.2

21.2 26.4 33.1 40.7 25.7 32.1 40.3 49.7 31.9 37.1 46.7 57.7 71.2 89.3 42.1 53.1 65.7 81.1

1 1.70 14.40 9.72 13.30 16.40 12.00 14.80 18.40 22.90 27.90

1.42 1.78 1.82 2.30 2.74 2.82 3.10 3.38 3.58 3.86 4.26 4.66 5.68 4.72 5.42 5.94 7.28 8.88 6.58 7.22 8.88 10.90 7.74 9.50 12.90 8.90 10.90 14.90 18.40 12.4 16.9 20.9 15.3 18.9 23.4 29.1 35.5

0.88 1.59 1.90

3.49 3.76 4.00

150 8.39

8.94 9.71 10.4 12.1 17.7 19.9 21.6 25.5 29.6

180

200 35.6

38.7 46.1 54.4 57.9 69.5

8.0

I O 12.5

16 6.3 8.0

10 12.5

16 6.3

8 O

I O 12.5

16 6.3

8 O

10 12.5

16

10 12.5

16 10.0 12.5 16.0 10.0 12.5

18.0 22.3 27.9 34.2 21.1 26.3 32.9 40.4 22.7 28.3 35.4 43.6 53.4 66.4 34.2 43.0 53.0 65.2 81.4 38.2 48.0 59.3 73.0 91.5 48.1 60.5 75.0 92.6 90.7

55.5

68.0 84.5 43.6 54.7 67.5 83.0

104 48.6 61.1 75.5 93.0

61.2 77.1 95.5

306 MECHANICAL ENGINEER’S DATA HANDBOOK Rectangular hollow steel sections (BS 4848:Part 2)

5.14 5.45 5.90 6.3 1 12.2 13.7 14.8 17.3 17.7 19.1 22.6 32.8 39.1 50.0 36.1 39.1 46.7 55.1 64.2 54.6 65.4 84.7 99.9 76.9 99.9

8 .O

10.0 12.5 16.0 300x200 6.3

8 O

10.0 12.5 16.0 400x200 10.0

12.5 16.0 450x250 10.0

12.5 16.0

22.7 28.9 28.3 36.0 35.4 45.1 43.6 55.5 53.4 68.0 66.4 84.5 38.2 48.6 48.0 61.1 59.3 75.5 73.0 93.0 91.5 117 48.1 61.2 60.5 77.1 75.0 95.5 92.6 118

117 149 90.7 116

1 .Ooo

1.12 1.25 1.40 1.60 1.80

2 00 2.24 2.50 2.80

0.250 0.265 0.280 0.300 0.315 0.335 0.355 0.375 0.400 0.425 0.450 0.475 0.500 0.530 0.560

0.600

0.630 0.670 0.710 0.750 0.800 0.850 0.900 0.950

1 .Ooo

1.06 1.12 1.18 1.25 1.32 1.40

1 S O 1.60 1.70 1.80 1.90 2.00 2.12 2.24 2.36 2.50 2.65 2.80

3.15 3.35 3.55 3.75 4.00 4.25 4.50 4.75

5 00 5.30 5.60 6.00 6.30 6.70 7.10 7.50

8 00 8.50

9 00

9.50 10.00 10.6 11.2 10.6 12.5 13.2 14.0 15.0 16.0 17.0 18.0 19.0 20.0 21.2 22.4 23.6 25.0

308 MECHANICAL ENGINEER’S DATA HANDBOOK

0.3.3 Copper pipe sizes for domestic

water pipes, etc

Size are given in BS 2871: Part 1

Nominal thickness (mm) Table X:

Size of Half-hard, Table Y: Table Z:

pipe* light half-hard, hard drawn,

1 .o

1 .o

1.2 1.2 1.5 1.5 2.0 2.0 2.5

0.5 0.5 0.5 0.5 0.5 0.6 0.6 0.6 7.0 8.0 9.0 1.2 1.2

Typical factors of safety for various materials

Type of load

Material

Varying, of

Grey cast iron

Malleable cast iron

Welds not subject to fatigue

Turbine blades and rotors

Gears: static load fatigue load Wire rope: general hoists

guys mine shafts lifts Springs: small, light duty small, heavy duty large, light duty large, heavy duty

1.25 2.0

5-1

3.5 5-8

7 12

2

3

3 4.5

8.4.2 Velocity of sound in various media

Solid

Velocity (m s- ') Liquid

Velocity

( m s - I ) Gas

Velocity (ms- ') Alumini

310 MECHANICAL ENGINEER’S DATA HANDBOOK 0.4.4 Greek alphabet

Glossary of terms

abrasion The process of rubbing, grinding or wearing

away by friction using an abrasive such as emery,

corundum, diamond, etc

abdste p m m r e Pressure measured from absolute

zero pressure as opposed to ‘gauge pressure’

aesdate tempentare Temperature measured with

respect to ‘absolute EM temperature’, units are ‘kel-

vin’ (symbol K) K=”C+273.15

accelerrtba The rate of change of velocity with

respect to time, (d2x/dt2) or R metres per second per

second (ms-*)

a.c III(IcLi.es machines producing or using alternat-

ing current, e.g alternator and a.c generator a.c

motors

A & k d u n The radial distance between the pitch

circle and the major diameter of a gear

dhcsivc Substances used for joining materials,

usually without the necessity for heat, based on natural

substances (animal bone, casein, rubber, etc.) or

synthetic resins

adiabatic proeess A thermodynamic process in which

there is no transfer of heat between the working

substance and the surroundings

a d d A body shaped so as to produce an appreci-

able ‘lift’, Le a force normal to the direction of fluid

flow relative to the body, and a small ‘drag’ force in the

same direction as the flow Aerofoil sections are used

for turbine blades, wing sections, etc

air-fuel ratio The ratio of the mass of air to mass of

fuel entering an internal combustion engine, gas

turbine or boiler furnace

air motor A motor which converts the energy of

compressed air into mechanical energy, usually as a

rotation The main types are axial or radial piston, and

vane

alloy A substance with metallic properties composed

of two or more chemical elements, at least one of which

is a metal

aUoy s t d Steel containing significant quantities of

alloying elements other than carbon and commonly

accepted amounts of manganese, sulphur, silicon and

phosphorus, added to change the mechanical and physical properties

altersrtingcenzllt Abbreviation a.c Electric current whose flow changes direction cyclicly The normal waveform is sinusoidal

alternator A type of a.c generator driven at constant speed to generate the desired frequency

anemometer A mechanical or electrical instrument

for measuring the velocity of a fluid stream, particular-

ly wind velocity The main types are, cup, vane and hot wire

aneroid buometer A barometer with a partially evacuated bellows chamber connected to a pointer with a pen recording atmospheric pressure on a drum chart The bellows responds to atmospheric pressure

angle gauges Sets of metal blocks with two opposite faces at various angles to one another, used separately

or jointly to measure angles to a high degree of accuracy

angular accekratioa The rate of change of angular velocity expressed in radians per second squared: d20/dt2 or # (rads-2)

angular momentom The product Iw of the moment

of inertia, I and the angular velocity o of a b o d y moving in a curve, e.g a flywheel

angular velocity The rate of change of angular dis- placement with respect to time, expressed in radians per second, dO/dt or 0 (rad s- ’)

atmedog Heating a metal to, and holding at, a suitable temperature and cooling at a suitable rate so

as to reduce hardness, improve machineability, ease cold working, etc

AreLimccles pri.Ciple States that a body wholly or partially submerged suffers an apparent loss of weight equal to the weight of fluid displaced

are wddiag A process for joining metals by fusion in which heat is produced by an electric arc

uitbmetic mean The sum of n numbers divided by n

aritbwrie prognssioa A series of numbers where each number is obtained by adding a fixed quantity to the previous number