*- -*r
*=$
In general, iron represents an alloy of iron and carbon. lt can have various peculiar featureswhen other metals are added such as nickel and chrome. The latter alloys are called"special steel".
Relation betwetheir Width acn
@OUnmarked n
applications.OMaterial for h
chromium-mclron
- Pure iron (carbon content 0.0060/o or less)
- Steel (carbon content 0.06% to 2.Oo/ol
r- Hard steel
[- Carbon steel II - Special steelL tvtilo steel
:i. f- Ordinary cast iron- Cast iron (carbon content=1.7o/o to 6.67%) |- Special cast iron
l-t Carnon steelCarbon steel is widely used because its properties can easily be changed by carboncontent or heat treatment.
Dead soft steel Rivet, split pinMild steel Section steel, steel
Semi-mild steel Bolt nutSemi-hard steel Gear shaft
Hard steel Shaft hammer
Extra hard steel tool
l-Z Special SteelSpecial steel is an alloy of iron, carbon and more than one other metals such as nickel,
chrome, tungsten, molybdenum, manganese and vanadium.
Special steel includes: nickel steel, chrome steel, nickel chrome steel, chrom
molybdenum steel and invar.Other special steel: high-speed tool steel (for tools such as tap and die), stainless
and silicon manganese steel (for spring).
M.MIMIM{
M1
MllMl t]tn2cM22M24M27M30M3ifM36M39M42M45
I cnuot " tt
rs peculiar featuresr alloys are called
Hard steel
Special steel
: i ron
ron
ranged by carbon
;teel, steel pipe
nmer
rls such as nickel,
s teel , chromium-
ie), stainless steel,
Relation between the Nominal Size of Hexagon Bolt and Hexagon socket Head Bolt andtheir Width across Flats (Spanner Size).
@OUnmarked nominat sizes are generatly used: Parenthesized ones are for special
applications.
OMaterial for hexagon socket head bolt: Heat treated carbon steel (S4SC, 515C) or type3chromium-molybdenum steel (SCM3).
lol
,r*fi wM
Unit: mm
lit pin
ffircChapter tt @
Thread pitch gauge:otto.t 37 whitworth thread)otto.t 56M, -158M, -159M (metric thread)OUftf (unified fine thread)
@ONominal size means the outside diameter for both metric and inch threads.Owhen a metric coarse thread and a metric fine thread have the same nominal size, the
fine thread has a smaller pitch than that of the coarse thread.Example
M6 (coarse thread): Outside diameter 6 mm ; pitch 1 mmMG (0.75 fine thread): Outside diameter 6 mm ; pitch 0.75 mm
OWhen a unified thread and a Whitworth (coarse) thread have the same nominal size,pitch is the same but the angle of thread differs.Example
1/4-20UNG (unified coarse thread): Outside diameter 1/4 inch; pitch 20 (No. ofper inch); angle of thread 60 deg.W114 (Whitworth coarse thread): Outside diameter 1/4 inch; pitch 20 (No. of crests
inch); angle of thread 55 deg.
O.llS has abolished Whitworth thread since 1968.
4t Uetaric flOAngle of thrOPitch: distalOUnit for non
4z uniriea rnOAngle of thnOUnit for nonOUnit for pitcl
4g WhirworrhOAngle of thnOoutside dianOUnit for pitcl
4l ttread Ty1OMetric coarsOMetric fine ilOUnified coarsOUnified fine tlOwhitworth cr
thread is 55 cOWhitworth finOeipe thread:
Combinationangle of threa
OgO deg. trapeOZg deg. trapei
Feature Metric screw Unified fine thread Whitworth threadle of thread 60" 6o' 55'
Unit for nominal size mm No. or inch Inch (coarse
Unit for Mm No. of crests per inch No. of crests oer inch
Sample expressionCoarse thread
M6\t.
1/4-UNC wl14
Fine thread M6X0.75 4-U28UNC
I(8 mm)
I(3/4 inch)
Angle
;h (coarse thread)l. of crests per inchv4
hitworth thread
rreads.me nominal size, the
4-t Vtetaric ThreadOAngle of thread: 60 deg.OPitch: distance between crestsOUnit for nominal size: mm
4-z unitied ThreadOAngle of thread: 60 deg.OUnit for nominal size: inch or No.OUnit for pitch: number of crests per inch (25.4 mm)
ne nominal size, the
ch 20 (No. of crests
20 (No. of crests per
4-g Whitworth Thread ( JIS has abolished this type of thread sine lgGS )OAngle of thread: 55 deg.OOutside diameter: inchOUnit for pitch: number of crests per inch (25.4 mm)
4a fnread TypesOMetric coarse thread: Expressed by "M", angle of thread is 60 deg.OMetric fine thread: Has smatl pitch. Angle of thread is 60 deg.OUnified coarse thread: Expressed by "UNC". Inch thread. Angle of thread is 60 deg.OUnified fine thread: Has small pitch. Inch thread. Angle of thread is 60 deg.OWnitworth coarse thread (abolished by JIS): Expressed by "\,V'. Inch thread. Angle of
thread is 55 deg.OWnitworth fine thread: Expressed by "\,V". Inch thread. Angle of thread is SS deg.OPipe thread:
Gombination of parallel thread and taper thread (PT, PF, PS) has small pitch and theangle of thread is 55 deg.
OgO deg. trapezoidal threadCZS deg. trapezoidal thread
chapter tt O
M1.2 0.25 0.2
Ml .6 0.35 0.2
M2 0.4 0.25
M2.5 0.45 0.35
M3 0.5 0.35
M4 0.7 0.5
M5 0.8 *,o.5M6 1 0.75
M8 1.25 1
0.75
M l 0 1 .5 1,25
1
0.75
M l 2 1.75 1 .5
1.25
1
(Ml4) 2 1 .5
1.25
1
M l 6 2 1 . 5
1
(M18) 2.5 2
1 . 5
1
M20
M24
(Mzn
(M30)
M36
(M3e)
2
1 .5
1
2
1 . 5
2
1 .5
1
2
1 . 5
1
2
1 . 5
1
2
1 . 5
3
2
1 .5
3
GilOUnmarked sizes are used by priority: parenthesized ones, only when necessary.OPitch gauge: No.l56M to -159M
OAngle of thread: 60 deg.
OAngle of threAngle of thre
OPitcrr gauge:
Thread 6 l{ominal SiieUnit: mm
114 6.350 20 28 20
5/16 7.938 1 8 24 1 8
1 6
1 4318 9.525 1 6 24
7116
112
11.112 1 4 20
12.700 1 3 20' 1 2
9/1 6
518
14.288 1 2 1 8 1 2
15.875 1 1 1 8 1 1
314 19.050 1 0 1 6 1 0
I718
1
22.225 9 1 4
25.400 8 1 2 I
1118 28.575 7 1 2 !71114
1318
31.750 7 1 2
34.925 6 1 2 961112
1314
2
38.100 6 1 2
44.450 5 5
50.800 4112 4112
2114 57.150 4112 !42112
2314
63.500 4
69.850 4 3112
3 76.200 4 3112
31123114
3112
82.550 4
88.900 4 3112
3314 95.250 4 I34 101 .600 4
etEffi.OAngle of thread (UNG): 60 deg.
Angle of thread (W): 55 deg.
OPitch gauge: UNC (for UNC thread); No.135 (for W)
!n necessary.
Pipe thread is mainly used to connect gas pipes (carlcon steel pipes for ordinary piping)and has a small pitch and the thread angle of 55 deg. There are two types of pipe thread :parallel thread (PF) and taper thread (PT).
OExpression :
Expressed by the nominal size in inch of the female thread which fits the mating malethread Fhe size is not equal to the outside diameter of the male thread but is almostequal to the bore of the pipe).
OOombination of pipe threadsParallel pipe thread : Taper mde thread (PT) and taper female thread (PT)Taper male thread (PT) and paral lel female thread (PS) (uPSu is used for thiscombination.)
@Parallel female thread (PS) is used in combination with taper male thread (PT).Specifications are the same for both PS and PT.
OSample expressionPS 1/4 : Pitch 19 (No. of crests per inch) ; outside dimension of thread = 13.157 mm
OPitch gauge:OAngle of threOPf thread ha
; for ordinary piping)ypes of pipe thread :
fits the mating malethread but is almost
, (PT)
i " i s used fo r th i s
male thread (PT).
d = 13 .157 mm
No
@OPitcn gauge: No.137OAngle of thread: 55 deg.OPf thread has a 1116 taper.
PS1/8 PS1/8 9.728 28 10 .5 6A
PS1/4 PS1/4 13 .157 1 9 13 .8 8A
PS3/8 PS3/8 16.662 1 4 17.3 104
PS112 PS112 20.955 1 4 21.7 . 15A
PS3/4 PS3/4 26.441 1 1 27.2 20A.PS1 PS1 33.249 1 1 34.0 254
PS13/4 PS13/4 41 .910 1 1 42.7 324PS1112 PS1112 47.803 1 1 48.6 404
PS2 PS2 59.614 1 1 60.5 50A
PS2112 PS2112 75.184 1 1 76.3 65A
PS3 PS3 87.884 1 1 89.1 80A
PS31/2 PS31/2 100.330 1 1 101 .6 90A
PS4 PS4 113.030 1 1 1 14 .3 1 00APS5 PS5 138.430 1 1 139.3 125A
PS6 PS6 163.830 1 1 165.2 1 50A
PS7 PS7 189.230 1 1 190.7 1 75A
PS8 PS8 214.630 1 1 216.3 200APS9 PS9 240.030 1 1 241.8 2254
PS1 O PS1 O 265.430 1 1 267.4 250APSl 2 PSl 2 316.230 1 1 . 318.5 300A
Chapter ll O