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  4. BS EN 14399-7 Specification

BS EN 14399-7 Countersunk Bolts & Nuts

BS EN 14399-7 Composition of high-strength structural bolting assemblies and component marking

Type of bolting assembly System HR System HV System HRC
General requirements EN 14399-1
Suitability for preloading EN 14399-2 and, if any, additional testing specified in the product standard
Bolt and nut EN 14399-3 EN 14399-7 EN 14 399-4 EN 14399-8 EN 14399-10
Marking Bolt HR8.8 HR10.9 HR8 .8 HR10.9 HV10.9 HVP10.9 HRC 10.9
Nut HR8 or HR10 HR10 HR8 or HR 10 HR10 HV 10 HV 10 HR 10 HRD 10
Washers EN 1439 9-5 a or EN 14399-6 EN 14399-6 EN 14399-5 8 or EN 14399-6
Marking H or HRb H or HV b H or HRb H or HRb or HD c
Direct tension indicator and nut face washer or bolt face washer, if any EN 14399-9 Not applicable
Marking Direct tension indicator H8 H10 H8 H10 H10
Nut face washer HN HN
Bolt face washer HB Not applicable HB
  • a EN 14399-5 can on ly be used under the nu t.
  • b At the choice of the manufacturer.
  • c Manda tory mark for washers with en larged outer d iame ter according to EN 14399-5 only

BS EN 14399-7 Dimensions

Dimensions of bolts

Threadd M12 (M14)a M16 (M18)a M20
Pb 1,75 2 2 2,5 2,5
b (ref.) c 30 34 38 42 46
d - 40 44 48 52
e - - - - 65
ds max. 12,70 14,70 16,70 18,70 20,84
min. 11,30 13,30 15,30 17,30 19,16
dk max. 24,00 28,00 32,00 36,00 40,00
min. 23,16 27,16 31,16 35,00 39,00
i max. 16,5 19,5 22,5 25,5 28,5
min. 15,5 18,5 21,5 24,5 27,5
k nom. 8,0 9,0 10,0 12,0 13,0
max. h 8,75 9,75 10,75 12,90 13,90
min. i 7,25 8,25 9,25 11,10 12,10
r max. 1,6 1,6 1,6 2,0 2,0
min. 1,2 1,2 1,2 1,5 1,5
n max. 3,0 3,0 3,0 3,5 3,5
min. 2,5 2,5 2,5 3,0 3,0
t max. 4,5 4,5 4,5 5,0 5,0
min. 3,0 3,0 3,0 3,5 3,5
l ls and lg f,g
nom. min. max. min. max. min. max. min. max. min. max. min. max.
45 43,75 46,25 - 15 . . . . . . . . . . . . . . . . . . . . . . . .
50 48,75 51,25 - 15 . . . . . . . . . . . . . . . . . . . . . . . .
55 53,50 56,50 16,25 25 . . . . . . - 18 . . . . . . . . . . . .
60 58,50 61,50 21,25 30 - 17 - 18 . . . . . . . . . . . .
65 63,50 66,50 26,25 35 21 31 - 18 . . . . . . - 23
70 68,50 71,50 31,25 40 26 36 22 32 . . . . . . - 23
75 73,50 76,50 36,25 45 31 41 27 37 - 22 - 23
80 78,50 81,50 41,25 50 36 46 32 42 25,5 38 - 23
85 83,25 86,75 46,25 55 41 51 37 47 30,5 43 26,5 39
90 88,25 91,75 51,25 60 46 56 42 52 35,5 48 31,5 44
95 93,25 96,75 56,25 65 51 61 47 57 40,5 53 36,5 49
100 98,25 101,75 61,25 70 56 66 52 62 45,5 58 41,5 54
110 108,25 111,75 . . . . . . 66 76 62 72 55,5 68 51,5 64
120 118,25 121,75 . . . . . . 76 86 72 82 65,5 78 61,5 74
130 128,0 132,0 . . . . . . 80 90 76 86 69,5 82 65,5 78
140 138,0 142,0 . . . . . . 90 100 86 96 79,5 92 75,5 88
150 148,0 152,0 . . . . . . 100 110 96 106 89,5 102 85,5 98
160 156,0 164,0 . . . . . . 110 120 106 116 99,5 112 95,5 108
Thread d M22 M24 M27 M30 M36
Pb 2,5 3 3 3,5 4
b (ref.) c 50 54 60 66 78
d 56 60 66 72 84
e 69 73 79 85 97
ds max. 22,84 24,84 27,84 30,84 37,00
min. 21,16 23,16 26,16 29,16 35,00
dk max. 44,0 48,0 54,0 60,0 72,0
min. 43,0 47,0 53,0 58,8 70,8
i max. 30,5 33,5 37,5 42,5 50,5
min. 29,5 32,5 36,5 41,5 49,5
k nom. 14,0 16,0 17,5 19,5 23,0
max. h 14,90 16,90 18,40 20,55 24,05
min. i 13,10 15,10 16,60 18,45 21,95
r max. 2,0 2,0 2,5 2,5 2,5
min. 1,5 1,5 2,0 2,0 2,0
n max. 3,5 3,5 3,5 4,0 4,0
min. 3,0 3,0 3,0 3,5 3,5
t max. 5,0 5,0 5,0 5,5 5,5
min. 3,5 3,5 3,5 4,0 4,0
l ls and lg f,g
nom. min. max. min. max. min. max. min. max. min. max. min. max.
65 63,50 66,50 - 24 . . . . . . . . . . . . . . . . . . . . . . . .
70 68,50 71,50 - 24 . . . . . . . . . . . . . . . . . . . . . . . .
75 73,50 76,50 - 24 - 28 . . . . . . . . . . . . . . . . . .
80 78,50 81,50 - 24 - 28 - 29,5 . . . . . . . . . . . .
85 83,25 86,75 - 24 - 28 - 29,5 . . . . . . . . . . . .
90 88,25 91,75 27,5 40 - 28 - 29,5 - 33,5 . . . . . .
95 93,25 96,75 32,5 45 - 28 - 29,5 - 33,5 . . . . . .
100 98,25 101,75 37,5 50 31 46 - 29,5 - 33,5 . . . . . .
110 108,25 111,75 47,5 60 41 56 35 50 - 33,5 - 39
120 118,25 121,75 57,5 70 51 66 45 60 36,5 54 - 39
130 128,0 132,0 61,5 74 55 70 49 64 40,5 58 - 39
140 138,0 142,0 71,5 84 65 80 59 74 50,5 68 - 39
150 148,0 152,0 81,5 94 75 90 69 84 60,5 78 46 66
160 156,0 164,0 91,5 104 85 100 79 94 70,5 88 56 76
170 166,0 174,0 . . . . . . 95 110 89 104 80,5 98 66 86
180 176,0 184,0 . . . . . . 105 120 99 114 90,5 108 76 96
190 186,0 194,0 . . . . . . 115 130 109 124 100,5 118 86 106
200 196,0 204,0 . . . . . . 125 140 119 134 110,5 128 96 116
  • NOTE The popular lengths are defined in terms of lengths ls min and lg max.
  • a Non-preferred s izes .
  • b P is the p itch of thread .
  • c For lengths lnom ≤ 1 25 mm .
  • d For lengths 12 5 mm < lnom ≤ 2 00 mm .
  • e For lengths lnom > 2 00 mm .
  • f lg max = lnom - b; ls min = lg max - 5P
  • g When ls min as calculated by the formula in f is less than knom + 0 ,5d then the bo lts shal l be ful ly threaded , and in this case lg max is equal to knom + 4P, where 4P is the value of amax as specified in ISO 3 508 for product grade C . Ful ly threaded bo lts are shown above the bo ld stepped l ine .
  • h kmax includes the he ight of embossed marking, if any.
  • i kmin excludes the height o f embossed marking, if any.

Dimensions of nuts

Threadd M12 (M14)a M16 (M18)a M20 M22 M24 M27 M30 M36
Pb 1,75 2 2 2,5 2,5 2,5 3 3 3,5 4
da max. 13,0 15,1 17,3 19,5 21,6 23,7 25,9 29,1 32,4 38,9
min. 12 14 16 18 20 22 24 27 30 36
dw max. c
min. 20,10 21,86 24,90 27,70 29,50 33,30 38,00 42,80 46,60 55,90
e min. 23,91 27,12 29,56 32,95 35,03 39,55 45,20 50,85 55,37 66,44
m max. 10,8 12,8 14,8 15,8 18,0 19,4 21,5 23,8 25,6 31,0
min. 10,37 12,10 14,10 15,10 16,90 18,10 20,20 22,50 24,30 29,40
mw min. 8,3 9,7 11,3 12,1 13,5 14,5 16,2 18,1 19,5 22,4
c max. 0,8 0,8 0,8 0,8 0,8 0,8 0,8 0,8 0,8 0,8
min. 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4 0,4
s max. 22 24 27 30 32 36 41 46 50 60
min. 21,16 23,16 26,16 29,16 31,00 35,00 40,00 45,00 49,00 58,80
t 0,38 0,42 0,47 0,52 0,58 0,63 0,72 0,80 0,87 1,05
  • a Non-preferred sizes .
  • b P is the pitch of thread .
  • c dw max = s actual

BS EN 14399-7 Specification and Reference standard

Specifications for bolts and reference standards

Material Steel
General requirements EN 14399-1 and EN 14399-2
Thread Tolerance class 6g a
International Standards ISO 261, ISO 965-2
Property class 8.8 or 10.9
Mechanical properties European Standard EN ISO 898-1
Tolerances Product grade C except for dimension r. Tolerance for lengths ≥ 160 mm: ± 4,0 mm
European Standard EN ISO 4759-1
Uncoated as processed c
Finish-Coatingb Hot dip galvanized EN ISO 10684
Others to be agreedd
Surface integrity Limits for surface discontinuities are covered in
Acceptability For acceptance procedure, see EN ISO 3269.
  • a The to lerance class specified app l ies to bo lts without or before any coating. Ho t-dip galvanized bo lts are intended for assemb ly with nuts tapped overs ize to 6AZ .
  • b Attention is drawn to the need to cons ider the risk of hydrogen embrittlement in the case of bo lts of property class 10 .9 , when selecting an appropriate surface treatment process (e .g. cleaning and coating) , see the relevant coating standards .
  • c “As processed” means the normal finish resulting from manufacture with a l ight coating of oil .
  • d Other coatings may be negotiated between the purchaser and the manufacturer provided they do not impair the mechanical properties or the functional characteristics . Coatings of cadmium or cadmium al loy are not permitted .

Specifications for nuts and reference standards

Material Steel
General requirements EN 14399-1 and EN 14399-2
Thread Coating of the bolt Uncoated Hot dip Others
Tolerance class ofthe nut 6H 6AZ 6Ha
International Standards ISO 261,ISO 965-2 ISO 261,ISO 965-5 ISO 261,ISO 965-2,ISO 965-5
Mechanical properties Property class 8 b or 10 b
European Standard EN ISO 898-2
Tolerances Product grade B except for dimensions m and c
European Standard EN ISO 4759-1 c
Finish-Coating Uncoated as processed d
Hot dip galvanized EN ISO 10684
Others to be agreed e
Surface integrity Limits for surface discontinuities as specified in
Acceptability For acceptance procedure, see EN ISO 3269.
  • a For other coatings that need an increased fundamental deviation and according to the relevant standard , overs size tapped nuts with a thread tolerance class up to 6AZ may be used .
  • b For mechanical properties other than those specified in EN ISO 898 -2 , see 4 .3 , Table 6 for proof load values for hardness values .
  • c Except tolerance on perpendicularity of bearing face , see tolerance t in Table 4 .
  • d “As processed” means the normal finish resulting from manufacture with a light coating of oil .
  • e Other coatings may be negotiated between the purchaser and the manufacturer provided they do not impair the mechanical properties or the functional characteristics . Coatings of cadmium or cadmium alloys are not permitted

BS EN 14399-7 Proof load values of nuts

Threadd Nominal stress area of standard test mandrel As Property class
8 10
Tolerance class 6H or 6AZ Tolerance class 6H or 6AZ
mm2 Proof load (As × Sp) , N
M12 84,3 84300 97800
(M14) 115 115000 133400
M16 157 157000 182100
(M18) 192 192000 222700
M20 245 245000 284200
M22 303 303000 351200
M24 353 353000 409500
M27 459 459000 532400
M30 561 561000 650800
M36 817 817000 947700
  • NOTE The proof load values are based on the following s tress under proof load (Sp) :
  • - for nuts o f property class 8 : 1 000 N/mm2;
  • - for nuts o f property class 10 : 1 160 N/mm2.

BS EN 14399-7 Hardness values of nuts , if specified

Nut Hardness limits
Property class 8, tolerance class 6H As specified in EN ISO 898-2 for property class 8
Property class 10, tolerance class 6H or 6AZ As specified in EN ISO 898-2 for property class 10
Property class 8, tolerance class 6AZ, hot dip galvanized 260 HV to 353 HV (24 HRC to 36 HRC)

BS EN 14399-7 Bolting Surface Treatment Specifications

BS EN 14399-7 Bolting Components Marking

Product Shall be Marked with our manufacturing trade mark "TorqBolt" or "TB" along with the designated Grade.
Grade and manufacturer’s identification symbols shall be applied to one end of studs and to the heads of bolts and screws of all sizes. (If the available area is inadequate, the grade symbol may be marked on one end and the manufacturer’s identification symbol marked on the other end.) For bolts and screws smaller than 1⁄4 in. [6 mm] in diameter and studs smaller than 3⁄8 in. [10 mm] in diameter and for 1⁄4 in. [6 mm] in diameter studs requiring more than a total of three symbols, the marking shall be a matter of agreement between the purchaser and the manufacturer.

ASME Dimensional Standards

BS EN 14399-7 Bolting Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103

BS EN 14399-7 Testing Standards

ASME Threading Specifications

BS EN 14399-7 Supplementary Requirements