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ASME 1999 818 Approved Revision B1B.2.3.1M
HEX
METRIC HEX CAP SCREWS
SCREWS
IFI NOTES:
I. ASME 818.2.3.IM Is a standard developed through the procedures of The American Society of Mechanical Engineers. B18.2.3.1M Is under the Jurisdiction of ASME Standards Committee B18 and Is the direct responsibility of its Subcommittee 2.
•
2. B1B.2.3.1M was first issued as an American National Standard in 1979 and then reaffirmed in 1989 and 1995. In 1997, a revision was initiated to try and bring this standard into closer agreement with ISO. A letter ballot of proposed revisions closed In November of 1998 and was not approved. Subcommittee 2 met In early December of 1998 and made changes to address the negatives. This presentation includes those approved changes and this revision was finally approved by the Committee in January of 1999. Users should consult with the 818 ASME Secretary for current status within ASME procedures.
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3. Key revisions in this approved revision include: It is made clear in Para. 5.1 that al/ dimensions In this standard apply before any coating has been applied. The washer face diameter is now to be inspected at 0.1 mm above the bearing plane and not at mid·thickness as it was previously. The length of point Is redefined, including a new method for check· ing an increased maximum point length defined In Table 7 and Para. 15. Screw straightness which formerly was checked with a sleeve gage is now checked with a rail gage as established in Para. 16. The position of body-t~thread which is checked with a sleeve gage now applies only to cut threads as established in Para. 18 with new tolerance zone values shown in Table 4. Grip length and body length have been revised to correspond to the ISO standard. This results in the following standard diameter/ length combinations being fully threaded and not partially threaded as they were previously. M8 x 35 M10 x 40 M12 x 45 M14 x 50 M14 x 55 M16 x 55 M16 x 60 M20 x 65
M20 x M24 x M30 x M36 x M36 x M36 x M42 x M42 x
70
80 100 110 120 130 150 140
M42 x 130 M42 x 120 M48 x 160 M48 x 150 M56 x 200 M56 x 180 M64 x 24(} M64 x 220
M64 x 200 M72 x 260 M72 x 240 M72 x 220 M80 x280 M80 x 260 M80 x 240 M90 x 320
M90 x 300 M90 x 280 M90 x 260 M100 x 340 M100 x 320 M100 x 300 M100 x 280
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HEX SCREWS
METRIC HEX CAP SCREWS
ASME 1999 B18 Approved Revision B18.2.3.1M
For screws threaded full length, the grip length is increased ap-proximately to 3 times pitch from 2.5 times pitch. See Table 2.
The previous requirement for a controlled root radius in the runout section of the thread on products of Property Class 10.9 or greater has been replaced by a requirement for a rounded root contour included in Para. 17.5.
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Quality assurance and dimensional conformance have been specified and included in Paras. 24 and 25, respectively. Appendix IV provides a detailed comparison of product characteristics in this standard as compared to those of ISO.
4. Referenced standards have been omitted in this approved revision of B1B.2.3.1M. For this information, refer to the complete ASME B18.2.3.1M latest revision, copies of which are available from The American Society of Mechanical Engineers, Three Park A venue, New York, NY 10016-5990, U.S.A.
1.
Scope
1.1 This standard covers the complete general and dimensional data for metric series hex cap screws recognized as American National Standard. 1.2 The inclusion of dimensional data in this standard is not intended to imply that all of the sizes in conjunction with the various options described herein are stock items. Consumers should consult with suppliers concerning lists of stock production hex cap screws.
2.
Comparison With ISO Standards
2.1 Hex cap screws, sizes M5 to M64, as presented in this standard are harmonized to the extent possible with ISO 4014 and for short screws threaded full length, with ISO 4017. Dimensional differences between this standard and ISO 4014 or ISO 4017 are few, relatively minor, and none will affect the functional interchangeability of screws manufactured to the requirements of either.
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The following functional characteristics of screws, sizes M5 through M14 with nominal lengths 2 times diameter through 10 times diameter, sizes M16 through M24 with nominal lengths 2 times diameter through 150 mm, and sizes M30 through M64 with nominal lengths 2 times diameter and longer, are in agreement between this standard and ISO 4014 or ISO 4017, as applicable: Nominal diameters and thread pitches Body diameters Widths across flats and corners, see Para. 2.2 Nominal head heights Nominal lengths and thread lengths Thread dimensions This standard omits sizes M1.6-M4, M18, M22. M27, M33, M39, M45, M52 and M60, which are included in ISO 4014 and ISO 4017. This standard includes sizes M10 x 1.5 with 15 mm width across flats, M72 x 6, MBO x 6, M90 x 6 and M100 x 6, which are not in ISO 4014 or ISO 4017.
ASME 1999 818 Approved Revision B1B.2.3.1M
HEX
METRIC HEX CAP SCREWS
K
----~.~I-
Kw
~ s~
Lg
•• Pa'"
See Para.
14
---t- See Para. 17.2
FILLET
+
SCREWS
- _.+-1 See Para. 17.4
12 iJ.-:::±- C
E
1
I
OPTIONAL POINT CONSTRUCTION SEE PARA. 15
15 0 _30°
PROPERTY CLASS AND SOURCE IDENTIFICATION TO APPEAR ON TOP OF HEAD
SEE PARA. 21
Table 1 Dimensions of Hex Cap Screws O.
0 Nominal
Screw ala and Thread Pitch M5)(0.8 M6x 1 MBx 1. 125
Ml0x'.5 Ml0)( 1.5 M12 x 1.75 M1 4)( 2
M16x2 M20 x 2.5 M24x3 M30 x 3.5 M36x4 M42 x 4.5 M48 x 5 M56 x 5.5 M64x6 M72x6 M80x6 M90x6 Ml 00 x 6 See Para NOTES:
Body Diameter
MI" '.82 5.82 e.oo 7.78 10.00 9.78 10.00 9.78 12.00 11.73 14.00 13.73 16.00 15.73 20.00 19.67 24.00 23.67 30.00 29.67 36.00 35.61 42.00 41.38 48.00 47.38 56.00 55.26 64.00 63.26 72.00 7 1.26 80.00 79.26 ".00 89. 13 100.00 99.13 13 M" 5.00 6.00
5
E
Width
Width Across Corners
Acros. Flats M" •. 00 10.00 13.00 15.00 16.00 18.00 21.00 24.00 30.00 36.00 46.00 55.00 65.00 75.00 85.00 95.00 105.00 115.00 130.00 145.00
MI" 7.78 9.78 12.73 14.73 15.73 17.73 20.67 23.67 29.16 35.00 45.00 53.80 62.90 72.60 82.20 91 .80 101 .40 111 .00 125.50 140.00
M" 9.24 11.55 15.01 17.32 18.48 20.78 24.25 27.7 1 34.64 41.51 53.12 63.51 75.06 86.60 98.15 109.70 121.24 132.72 150.11 167.43
MI" • .79 11.05 14.38 16.64 17.77 20.03 23.35 26.75 32.95 39.55 ".85 60.79 71.71 82.76 93.71 104.65 115.60 126.54 143.07 159.60
e. 9
K
K.
Head
Wrenching
Height
Height
M" 3.65 4.15 5.50 6.63
6.63
Min 3.35 3.85 5.10 6.17 6.17 7.24 8.51
MI"
12.12 14.56 17.92 21 .62 25.03 28.93 33B. 38." 4355 48.42
••• 10.5
.... .... 7.76
10.32 12.88 15.44 19.48 23.38 26.97 31 .07 36.20 41 .32 46.45 51 .58 57.74 63.90
7
2.'
2. 3.7
' .5 ' .5 5.2 6.' 7.'
C
O.
Washer
Washer
F.re
Face 01.
Thickneaa M" 0.5 0.5 0.6 ' .6 0.6 '.6 0.6
MI"
0 .• 0.8 0.8 1.' 1.. 1.0
0.'
33~
'.5
42.7 51 .1 59.8 69.0 78.1
O~
' .2 '.3 ' .3 ' .3 '.3 0.3
18~
•••••• •••••• •• ••••
21 .0 245
' .5 ' .5
13.1 15.8
28.' 31 .5 35.0
54~6
39~
60.10
43.'
•
I.'
MI" 7.0
••
11 .6 13.6 14.6 16.6 19.6 22.49 27.7
,
I
87~
••• ..., •••• •• '.5
1.2 1.2 1.2 12
' .6
11
105.4 119.2 133.0 11
1. All sizes except lh e loltowi ng are included in ISO 4014and ISO 4017: Ml 0 x 1.5wilh 15 mm WAF, and M72thru MlOO. 2. Unle ss M10 screws with 15 mm width across flats are specificaltyordered, Ml0 screws with 16 mm width across l!ats shall be fumished. 3. SeePara.2.1 Iorboidtype.
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HEX SCREWS
ASME 1999 818 Approved Revision B18.2.3 .1M
METRIC HEX CAP SCREWS
Table 2 Maximum Grip Gaging Lengths l.g and Minimum Body Lengths L. Nom Ola .od
MS .. 0.8
MS .. ,
M8 .. 1.25
MIO .1.5 M12 .. 1.75
Mt ... 2
MI6" 2
M20 " 2.5
MU,. 3
M30" 3.5
Ma6 .. 4
Thread Pitch L Nomi",1
l ength
I
L, L, L, M.. Min Mu
L, L, Min Mu
L, M'.
L, L, L, Mu M'. M"
,
L
L, Mu
L,
L, Mu
L, M'.
L, Mu
3.0
' .9
16
,.,,..,• ,.
3.0
'.0
2>
,-'
3.0
'.0
' .5
...2.
3.0
20
" ".,
90
3.0
'.0
' .5
5.3
3.0
3.0
'0
' .5
5.3
6.0
3.0
3.'
19.0 15.0 17.0 12.0 '.0
'.5
5.3
'.0
•••
'.3
' .0
'.0 M
3.'
24.0 20.0 22,0 17,0 18.0 11.75
S 10 12
30
"SO
" "
60 70
80 90
'00 110 120
,'" ,.,
".
M'.
M'.
L,
M'.
L, M"
L,
M'.
L, Mu
L,
M'.
L, Mu
L,
M'.
,"5
5.0
14.0 10.0 12.0 7.0
29.0 25.0 27.0 22.0 23.0 16.75 19.0 11 .5
'.3 "0 30.0 32.0 27.0 28.0 21 .75 24.0 165 20.0 11 .25 37.0 32.0 33.0 26.75 29.0 21 .5 25.0 16.25
I ,
3.0
' .0
I
'.0
M
' .0
9.0
7.'
9.0
10.5
7.'
9.0
10.5
7.'
9.0
10.5
12.0
'.0
7.5
9.0
10.5
12.0
16.0
' .0
7.5
9.0
10 .5
12.0
31 .0 21.0
27.0
17.0
7.'
90
10.5
12.0
"'.0 31.25 36.0 26.0 32.0 '"'0 51.75 " .0 46.5 SO.O 41.25 46,0 360 42.0 " .0 ".5 60.0 51.25 " .0 46.0 " .0 74.0 86.5 70.0 61.25 " .0 " .0 82.0
22.0
7.'
9.0
10.5
12.0
32.0
9.0
10.5
12.0
42.0
" .0 « .0
31.5
36.0
2 1.0
10.5
12.0
".0
" .0
41 .5
.. 0
31 .0
10.S
12.0
80.0 71 .25 76.0 " .0 n.o 90.0 81.25 68.0 76.0 82.0
62.0
".0 74.0
515
« .0
61.5
".0 86.0
4 1.0
72.0
51 .0
90.0 80.0 86.0
76.0
78.0
65.5
70.0
55.0
".0 58.0
100.0 90.0 98.0
68.0
" .0 96.0
75.5
".0
65.0
85.'
90.0
75.0
".5
90.0
85.0
42.0 37.0 38.0 3 1.75 " .0 26.' 30.0 2 1.25 "0 36.75 39.0 31.5 350 26.25
' .0 26.0
48.0 41.15 " .0 36.'
106.0
96.0
116.0 106.0 108.0
21.5
".0 78.0
26.5
12.0
36.'
.,..
12.0
SO.,
56.0
36.0
60.'
66.0
46.0
705
76.0
12.0
200
" .0 " .0 128.0 115.5 120.0 105.0 108.0 90.' 96.0 76.0 148.0 135.5 140.0 125.0 128.0 110.5 118.0 98.0
220 ,.,
137.0 152.0 155.0 137.5 143.0 123.0
260
175.0 157.5 163.0 143.0
'0)
'00
147.0 132.0 135.0 117.5 123.0 103.0
280
195.0 In .5 163.0 163.0
300
215.0 197.5 200.0 183.0
NOTES:
1. Diameter-length combinations between the thin stepped lines are recommended. 2. Screws with lengths above the thick stepped lines are threaded fUll length. See Table 3. 3. Forscrews of larger sizes andlorwith lengths longer than the lower stepped lines, ~ and L. values shall be computed from the fonnulasgiven In Para. 17 of General Data. 4. SeePara. 2.1forboldlype.
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ASME 1999 818 Approved Revision B18.2.3 .1M
HEX
METRIC HEX CAP SCREWS
SCREWS
Table 3 Thread Lengths Threa d Length, Ref
Nom inal $crew Dia
.n.
Thread Pitch
Sc.ew Lengths
L S 125
M5 xO.8 M6x 1 MS)( 1.25
22
MIO )( 1.5
26
M12l( 1.75
30
M14x2 M16 x2 M20 x 2.S
38
IS
18
Sc_ Lengths
L > 125 &
< 200 22 24 28
-
M90x6 Ml 00 x 6
Under
Ma>
At Least
Under
Ma>
fO 12
10 12
25
20 24
1.2 1.5 f.. 2.2 2.6
50
2A 3.0 4.0 4.5 5.3
60 65 80 80 110
6.0 6.0 7.5 '.0 10.5 12.0 13.5 15.0 16.5 18.0
18.0 18.0 18.0 18.0
Lengths
L
2B 32 40
3.0 3.0 3.8
32
-
-
-
97 109 121 137 153
20.0 22.5 25.0 27.5 30.0
-
-
-
-
140 160 180 220 260
16' 185 205 225
30.0 30.0 30.0 30.0
-
-
-
280 300 340 360
84
M72 )(6
Unthreaded loogth Under Hea d
10.0 10.0 12.5 15.0 17.5
-
-
Unthreaded Length Under Head
L
Lengths
53 57 65 73 85
M36x4
-
Length, R,f
A
""',w
32 36
46 54 66
M42x 4.5 M48x5 M56x 5.5 M64xS
Th" ••
A
4.0 5.0 6.25 7.5 8.75
M24 x3 M30 x 3.5
34
Transftlon
Screw Lengths L >200
w
Sc ..
37 41 45 49
40 44 52 60 72
MSO)(6
Scre ws Threa ded Full Len gth
(X)
(e )
96 108
-
-
35
"
-
-
-
"
20 24 28 40
'"
40 45
I
NOTE: See Para. 2.1 forbold type.
This standard specifies some requirements which are not included in ISO 4014 or ISO 4017. Dimensional requirements shown in bold type differ from, or are in addition to, ISO 4014 and/or ISO 4017, or, for sizes over M64, other relevant non product ISO standards. The technical differences between this standard and the ISO standards are summarized in Appendix IV, page C- 1S.
2.2
At its meeting in Varna, May 1977, (SOl
TC2 studied several technical reports analyzing design considerations influencing determination of the best series of width across flats for hexagon bolts, screws and nuts. A primary technical objective was to achieve a logical ra-
tio between the head or nut bearing surtace area (which determines the magnitude of the compressive stress on the bolted members) and the tensile stress area of the screw thread (which governs the clamping force that can be devel-
oped by tightening the fastener). M 10 screws with 15 mm width across flats are currently being produced and used in U.S.A. and many other countries of the world . T his size, however, is not an ISO standard. Unless M 10 screws with 15 mm width across flats are specifically ordered, M10 screws with 16 mm width across flats shall be fumished . 2.3 Letter symbols designating dimensional characteristics are in accord with ISO 225 and
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HEX
---
METRIC HEX CAP SCREWS
SCREWS
Table 4 Tolerance Zones Position of Head-to-Shsnk
Circular Runout of
Tolerance Zone Dla
Surface-ta-Shank FlM
Nominal Scr9W Ola
•••
Thread Pitch
MS x 0.8 M6 x 1 M8x 1,25
at MMC 0.35
Bearing
Position of Body-to-Thread To lerance Zone Dla at MMC
02 2
0.84
0.15 0.15 0. 17 0.2 1 0.25
2 2.5 3 3.5
0.98 1.12 1.40 1." 2.10
0.29 0.34 0.42 0.50 0.63
0. 27 0.27 0.33 0.33 0.52
M36x 4 M42 x 4,5 M48 x S M56x 5.5 M&1 x6
2.52 2.94 3.36 3.92 4.48
0.76 0. 44 0.50 0.59 0.67
M721{ 6 MSO x 6 M90k6 M,Oa x 6
5.04 5.60 6.30 7.00
0.75 0.84 0.94 1.05
0.74 0.74
See Para.
10
11
18
Ml 0x l .S M' 2 x 1.75
I
ASME 1999 8'8 Approved Revision B1B.2.3.1M
M14 x2 M1 6x M20 x M24 x M30 x
0.44
0.56 0.70
,
I
0.18 0.18
,
0.22 027
0.62
0.62 0.62 0.74 0.74
0.87 0.87
NOTE:
See Para. 2. 1 forbold type.
with ISO 4014 and ISO 4017, except where capitals have been used instead of the lower case letters used in the ISO standards. 3.
Referenced Standards
Unless otherwise specified, the standard referenced shall be the most recent issue at the time of order placement. Titles and sources of availability of all documents referenced in this standard are given on page K-41. 4. Terminology. For definitions of terms relating to fasteners or component features thereof used in this standard , refer to ASME B18.12. See page K-37 . 5.
Dimensions
5.1 All dimensions in this standard are in millimeters, (mm), and apply before any coating, unless stated otherwise.
nti. C-6
5.2 Symbols specifying geometric characteristics are in accord with ASME Y14.SM. 6. Top of Head. The top of head shall be full form and chamfered or rounded . The di· ameter of the chamfer circle or the start of rounding shall be equal to the maximum width across flats, S max, within a tolerance of minus 15 percent. 7. Head Height. The head height, K, is the distance, parallel to the axis of the screw, from the plane of the bearing surface to the top of the head, not including any raised markings. See Para. 21. 8. Wrenching Height. The wrenching height, '"", is the distance, measured at a corner of the hexagon, from the plane of the bearing surface to the last plane of full-formed hexagon, Le., the plane closest to the top of head at
ASME 1999
a1a Approved Revision
HEX
METRIC HEX CAP SCREWS
SCREWS
B18.2.3.1M
FILLET SHAll LI E WITHIN THIS ENVELOPE
FILLET SHALL LIE WITHIN THIS ENVELOPE~
Da
j
j
rna
L"
I
Lt
Fig. 2 Fillet Detail for Long Screws
Fig. 1 Fillet Detail for Short Screws
Table 5 Dimensions of Underhead Fillets
D. Nom inal Screw Dia • nd Thread Pit ch
D. ,
R
Lft
Lt
Fillet
Fillet Transition Diameter
length
For Short' a nd long Sc rews
Fo.
Fo.
Fo.
Short
Long
Screwsl
Screws
Short Screws'
Mu
Min
Ma.
5 .7 6.8 9.2 11.2 13.7
5.1 6.2 8.3 10.2 12.2
15.7 17.7 22.4 26.4 33.4
4
39.4
4 .5
-
M64 x6
45.6 52.6 63.0 71 .0
M72 x 6 MSO x 6 M90x6 M100 x 6
79.0 87.0 97.0 107.0
-
MS x 0.8
M6x 1 Ma x 1.25
Ml0 x 1.5 M12 x 1.75
M14 x 2 M16 x 2
M20 x 2.5 M24x 3 M30 x 3.5 M36 x M42 x M48 x M56 x
5 5.5
Dsi
Fillet Radiu s
Body Diameter
For Short' and Long
Short
Fo •
$crews
Screws'
Ma.
Mln
Mln
1.2 1.4 2.0 2.0 3.0
0.7 0.9 1.1 1.2 1.3
0.2 0.25 0.4 0.4 0.6
4.36 5.21 7.04 8.86 10.68
14.1 16.5 20.7 24.5 30.8
3.0 3.0 4.0 4.0 6 .0
1.4 1.6 2.1 2.3 3.0
0 .6 0.6 0 .8 0.8 1.0
12.50 14.50 18.16 21.80 27.46
36.6
6 .0 8.0 10.0 12.0 13 .0
3 .1 3 .4 4.0 4.8 5.0
1.0 1.2 1.6 2.0 2.0
33.12 38.78 44.43 52.09 59.74
13.0 13.0 13.0 13.0
5.0 5.0 5 .0 5.5
2.0 2.0 2.5 2.5
67.74 75.74 85.74 95.72
--
- - ~. --
-
-
,
-
NOTES: 1. Short screws are screws which are threaded fulllenglh. 2. For bold type see Para. 2. 1. 3. 0 01 min is the minimum pitch diameter.
1Ifi. C-7
HEX
METRIC HEX CAP SCREWS
SCREWS
which the hexagon width across corners, E, is within its specified limits.
9.
Corner Fill. The rounding due to lack of
fill at the six corners of the head shall be reasonably uniform.
10.
I
True Position of Head. At maximum ma-
terial condition, the axis of the hexagon head shall be within a positional tolerance zone of the diameter specified in Table 4 with respect to the axis of the shank over a length under the head equal to the nominal screw diameter, D.
11 .
Bearing Surface. The bearing surface
shall be flat and washer-faced. The diameter of the washer face, measured at 0.1 mm above the bearing surface, shall not exceed the actual width across flats, S, nor be less than the specified minimum washer face diameter, 0 wmin. The circular runout of the bearing surface with re· spect to the axis of the shank shall be within the full indicator movement (FIM) as specified in Table 4. The measurement of bearing surface runout shall be made as close to the periphery of the bearing surface as possible, while the screw is held in a collet or other gripping device at a distance of one diameter under the head.
ASME 1999 818 Approved Revision B18.2.3.1M
in Table 5. The fillet shall be a smooth and continuous curve fairing smoothly into the bearing surface and the shank within the limits speci fied. No radius in the fillet contour shall be less than R min. Body Diameter. The diameter of the 13. body on screws which are not threaded full length shall be within the limits for Os specified in Table 1. For screws threaded full length, the diameter of the unthreaded shank under the head shall not exceed the specified maximum body diameter, Os max, nor be less than the minimum body diameter, Dill min, specified in Table
5. 14.
length. The length, l , of the screw is
the distance, parallel to the axis of the screw, from the bearing surface to the extreme end of the shank. Tolerances for screw lengths are given in Table 6. 15. Points. The end of the screw shall be chamfered or rounded from a diameter equal to or slightly less than the thread root diameter. The length of the point to the first full formed thread at major diameter, as determined by the distance the point enters into a cylindrical NOT GO major diameter ring gage, shall not exceed U max, specified in Table 7. The end of the screw shall be reasonably square with the axis of the screw, but the slight rim or cup resulting from roll·threading shall be permissible. At the manufacturer 's option, the end of the screw may have a rounded point of radius R. speci-
fied in Table 7. 16. Straightness. At maximum material con· dition, the axes of the screw body and thread major diameter shall be within a straightness tol· erance diameter equal to 0.006L for nominal 12. Fillet. The fillet configuration at the junc· tion of the head and shank shall be as shown in Figs. 1 and 2, and shall have limits as specified
1Ifi. C-8
lengths (l ) 300 mm or shorter, and O.OOal for screws having nominal lengths (L) over 300 mm thru 600 mm. A gage and gaging procedure for checking straightness is given in Appendix 11.
ASME 1999 818 Approved Revision B18.2.3.1M
HEX
METRIC HEX CAP SCREWS
Table 6
Length Tolerances Nominal Screw Diameter
Nominal Length
over
thru
MS
MS
M8
Ml0
6
10
± 0.29
± 0.29
± 0.29
± 0.29
10
18
± 0.35
± 0.35
± 0.35
:t
0.35
± 0.35
18
30
±
0.42
±
0.42
± 0.42
%
0.42
±
30
50
± 0.50
::I:
0.50
±
50
60
±
0.60
±
60
80
80
100
1.50
120
120
140
140
150
0.50
± 0.60
M12
± 0.50 ±
0.60
±
0.70
±
1.75
M14
±
0.35
M16-M24
:>
M24
± 0.35
0 .42
± 0.42
±
0.42
::I:
1.05
± 0.50
± 0.50
±
0.50
±
1.25
0.60
± 0.60
±
0.60
:;I:
1.50
0.70
±
0.70
± 1.75
±
I
± 1.50 ± 1.75
100
SCREWS
±
1.75
±
1.75
± 0.70
:t
± 0.80 ± 0.80 ±
2.00
±
2.00
±
2.00
±
2.00
± 2.00
± 2.00 ±
2.00
150
180
180
250
±
2.30
± 2.30
±
2.30
± 2.30
:t
2.30
±
2.30
± 2.30
± 2.30
250
3 15
± 2.60
± 2.60
± 2.60
± 2.60
±
2.60
±
2.60
:t
2.60
± 2.60
3 15
400
± 2.85
± 2.85
±
2.85
± 2.85
± 2.85
± 2.85
± 2.85
±
400
500
±
3. 15
±
3. 15
±
3. 15
± 3. 15
±
3.15
± 3.15
± 3.15
±
3. 15
±
2.00
2.85
All tolerances are plus and minus.
17.
Thread Length
17.1 The length of thread on screws shall be controlled by the maximum grip length, Lg, and the minimum body length, Ls ' as set forth in 17.2 through 17.5. 17.2 Grip gaging length , L , is the distance, measured parallel to the axisgof the screw, from the underhead bearing surface to the face of a standard GO thread ring gage which is neither counterbored nor countersunk , assembled by hand as far as the thread will permit. For standard diameter-length combinations of screws, M5 to M36, the values for Lg max are specified in Table 2. For diameter-length combinations not listed in Table 2:
The maximum grip length of screws which are not threaded full length is equal to the nominal screw length, L nom , minus the basic thread length, (B), specified in Table 3: L, max ~ L nom - (8). For short screws of nominal lengths, L, which are shorter than the lengths specified in Table 3 for screws threaded full length, L 9 max = A max, specified in Table 3. 17.3 Body length, Ls ' on screws which are not threaded full length, is the distance, parallel to the axis of the screw, from the bearing surface to the last scratch of thread or top of the extrusion angle, whichever is closer to the head. For standard diameter-length combinations of
11fi. C-9
ASME 1999
HEX
METRIC HEX CAP SCREWS
SC REWS
Table 7 Dimensions of Points Nominal Screw Cia and Threa d Pitch MS '" 0.8
I
R.
U
Po int Radius
Point Length
Approx
Mu
7.0 8.4
1.60 2.00 2.50 3.00
M6,1 MS" 1.25
11.2
M ID x 1.5
14.0
M12 x 1.75 M14 x2 MI6 x 2 M20 x 2.5
16.8 19.6 28.0
3.50 4.00 4.00 5.00
M24,, 3 M30 )(3.5 M36x 4 M42 >
