June 2004
D EUTSCHE NORM NORM
{
Thread run-outs and thread undercuts for ISO metric threads as in DIN 13-1
76-1 Supersedes December 1983 edition.
ICS 21.040.10 Gewindeausläufe und Gewindefreistiche – Teil 1: Für Metrisches ISO-Gewinde nach DIN 13-1
In keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker.
Foreword This standard has been prepared by Technical Committee Fachgrundnormen Fachgrundnormen of the Normenausschuss Mechanische Verbindungselemente (Fasteners Standards Committee). It is based on International Standards Standards ISO 3508 : 1976 and ISO 4755 : 1983. As a departure from ISO 4755, which specifies only one type of thread undercut with g 2 max = 3 P, this standard specifies two types, i.e. type A with wit h g 2 max = 3,5 P (normal design) and type B with g2 max = 2,5 P (short design). Type B thread undercuts are intended for use on a case-by-case basis, where required for technical reasons; the use of special tools is necessary here. It should be noted that ISO 3508 and ISO 4755 do not contain specifications for thread run-outs and thread undercuts for internal threads. Ame ndm ndment ent s This standard differs from the December 1983 edition in that it has been editorially revised. Previous editions DIN 2352: 1924-11; DIN LON 369-1 = DIN 30140-1:1936-12; DIN 76-1: 1924-09, 1943-04, 1953-11, 1965-09, 1967-06, 1975-09, 1983-12.
All dime nsio ns are in mill millimet imet res. 5 5 : 6 1 1 2 7 0 5 0 0 2 1 0 0 1 3 9 2 8 8 2 . r N f L 5 3 5 9 3 0 6 . r N d K H b m G s m e t s y S c o l b i b m o C G I S h t u e B d a o l n w o D n e m r o N
1
Sc op e
This standard specifies dimensions for thread run-outs and thread undercuts for bolts, screws and similar components with external external or internal ISO metric (coarse or fine pitch) thread thread as in DIN 13-1 and DIN ISO 261.
2
Norm No rmat ativ ive e re refe fere renc nces es
This standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the titles of the publications are listed below. For dated references, subsequent amendments to or revisions of any of these publications apply to this standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. DIN DI N 1313-1 1 DIN 76DIN 76-2 2 DIN DI N 7676-3 3 DIN EN EN 28839
Genera Gene rall pur purpo pose se IS ISO O met metri ric c scr screw ew th thre read ads s – Nom Nomin inal al si size zes s for for 1 mm mm to to 68 68 mm mm dia diame mete terr coarse pitch threads Threa Thr ead d run run-o -out uts s and and th thre read ad un unde derc rcut uts s for for pi pipe pe th thre read ads s con confo form rmin ing g to to ISO ISO 22 2288-1 1 Threa Thr ead d runrun-ou outs ts and and thr threa ead d unde underc rcut uts s for for trap trapez ezoi oida dall thre thread ads, s, but buttr tres ess s thre thread ads, s, knu knuck ckle le threads and other coarse pitch threads Mechanica Mech anicall properties properties of fasteners fasteners – Bolts, Bolts, screws, screws, studs and and nuts made of non-ferr non-ferrous ous metals (ISO 8839 : 1986) Document comprises 5 pages. Translation by DIN-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text.
© No part of this translation translation may be reproduced reproduced without the prior permission permission of DIN Deutsche Deutsches s Institut Institut für Normung Normung e. V. , Berlin. Beuth Verlag GmbH, GmbH , 10772 Berlin, Germany, Germany, has the exclusive right of sale for German Standards (DIN-Normen) .
English price group 7 www.din.de www.beuth.de
10.04
9587848
P ag e 2 DIN 76-1 : 2004-06 DIN EN ISO 898-1 DIN ISO 261 ISO 3508 : 1976 ISO 4755 : 1983
3
Mechanical properties of fasteners made of carbon steel and alloy steel – Part 1: Bolts, screws and studs (ISO 898-1 : 1999) ISO general purpose metric screw threads – General plan (ISO 261 : 1998) Thread run-outs for fasteners with thread in accordance with ISO 261 and ISO 262 Fasteners – Thread undercuts for external metric ISO threads
Dimensions and designation
3.1
External threads
3.1.1 Thread run-outs Thread run-out dimensions shall be as given in figures 1 and 2 and table 1.
Key to figure 1 S han k di ame te r
R
pitch diameter Figure 1: Thread run-out dimensions (notation)
3.1.2
5 5 : 6 1 1 2 7 0 5 0 0 2 1 0 0 1 3 9 2 8 8 2 . r N f L 5 3 5 9 3 0 6 . r N d K H b m G s m e t s y S c o l b i b m o C G I S h t u e B d a o l n w o D n e m r o N
Distance from last full form thread to bearing face, a (for fully threaded components)
Figure 2: Dimension a (notation) 3.1.3 Thread undercuts Thread undercut dimensions shall be as given in figure 3 and table 1. It should be noted that fasteners with thread undercut do not meet the requirements for minimum breaking load as specified in DIN EN ISO 898-1 o r minimum breaking torque as specified in DIN EN 28839. Type A , with g 1 and g 2 of normal design Type B, with g 1 and g 2 of short design
Figure 3: Thread undercut dimensions (notation)
P ag e 3 DIN 76-1 : 2004-06 Designation of a type B thread undercut (B):
Thread undercut DIN 76 – B Table 1: Dimensions of thread run-outs and thread undercuts for external threads Thread run-out Thread pitch P
5 5 : 6 1 1 2 7 0 5 0 0 2 1 0 0 1 3 9 2 8 8 2 . r N f L 5 3 5 9 3 0 6 . r N d K H b m G s m e t s y S c o l b i b m o C G I S h t u e B d a o l n w o D n e m r o N
Nominal diameter(s),
x1
d
x2
Distance a
1
Max.
a
2
Thread undercut a
3
dg
Max.
(coarse thread)
g2
r
Min.
Max.
Type A Type B Type A Type B Normal 1 )
Short 2 )
Normal 3 )
Short 4 )
Long 5 )
h13 6 )
d – 0,3 d – 0,4 d – 0,5
0,45
0,25
0,7
0,5
0,1
0,55
0,25
0,9
0,6
0,12
0,6
0,3
1,05
0,75
0,16
d – 0,6 d – 0,7 d – 0,7
0,7
0,4
1,2
0,9
0,16
0,8
0,5
1,4
1
0,2
1
0,5
1,6
1,1
0,2
d – 0,8 d – 1 d – 1,1
1,1
0,5
1,75
1,25
0,2
1,2
0,6
2,1
1,5
0,4
1,5
0,8
2,45
1,75
0,4
d – 1,2 d – 1,3 d – 1,6
1,6
0,9
2,6
1,9
0,4
1,7
0,9
2,8
2
0,4
2,1
1,1
3,5
2,5
0,6
d – 2 d – 2,3 d – 2,6
2,7
1,5
4,4
3,2
0,6
3,2
1,8
5,2
3,8
0,8
3,9
2,1
6,1
4,3
1
d–3 d – 3,6 d – 4,4
4,5
2,5
7
5
1
5,6
3,2
8,7
6,3
1,2
6,7
3,7
10,5
7,5
1,6
7,7 9
4,7 5
12 14
9 10
1,6 2
10,5
5,5
16
11
2
11,5
6,5
17,5
12,5
2,5
12,5
7,5
19
14
3,2
14
8
21
15
3,2
0,2
–
0,5
0,25
0,6
0,4
–
0,25
1; 1,2
0,6
0,3
0,75
0,5
–
0,3
1,4
0,75
0,4
0,9
0,6
–
0,35
1,6; 1,7; 1,8
0,9
0,45
1,05
0,7
–
0,4
2; 2,3
1
0,5
1,2
0,8
–
0,45
2,2; 2,5; 2,6
1,1
0,6
1,35
0,9
–
0,5
3
1,25
0,7
1,5
1
–
0,6
3,5
1,5
0,75
1,8
1,2
–
0,7
4
1,75
0,9
2,1
1,4
–
0,75
4,5
1,9
1
2,25
1,5
–
0,8
5
2
1
2,4
1,6
3,2
1
6; 7
2,5
1,25
3
2
4
1,25
8
3,2
1,6
3,75
2,5
5
1,5
10
3,8
1,9
4,5
3
6
1,75
12
4,3
2,2
5,25
3,5
7
2
14; 16
5
2,5
6
4
8
2,5
18; 20; 22
6,3
3,2
7,5
5
10
3
24; 27
7,5
3,8
9
6
12
3,5 4
30; 33 36; 39
9 10
4,5 5
10,5 12
7 8
14 16
4,5
42; 45
11
5,5
13,5
9
18
5
48; 52
12,5
6,3
15
10
20
5,5
56; 60
14
7
16,5
11
22
6
64; 68
15
7,5
18
12
24
The dimensions specified are approximately equal to
g1
2,5 P
1,25 P
3 P
2 P
4 P
d – 5 d – 5,7 d – 6,4 d – 7 d – 7,7 d – 8,3
(normal) 7 ) (short ) 8 ) (normal) 7 ) (short ) 8 )
–
–
–
1 )
x1 to be used where no other indications are made in product standards or on drawings.
2 )
x2 to be used where a short thread run-out is required for technical reasons.
3 ) a to 1 4 ) a to 2
3,5 P
2,5 P
0,5 P
be used where no other indications are made in product standards or on drawings.
be used for slotted and cross recessed head screws and in cases where a short distance is required for technical reasons.
5 ) a to be used for screws assigned to product grade C. 3 6 ) Toleran ce h12 for sc rew th reads u p to 3 mm n ominal diamet er. 7 )
Type A to be used w here no other i ndicat ions are mad e in p roduct stand ards o r on d rawings .
8 )
Type B to be use d where a shor t thre ad und ercut i s requ ired f or tec hnical reason s.
P ag e 4 DIN 76-1 : 2004-06
3.2
Internal threads (blind tapped holes)
3.2.1 Blind tapped holes with thread run-out The dimensions of blind tapped holes with thread run-out shall be as given in figure 4 and table 2.
) 3
) 2
1 )
Key to figure b Useful thread length Limi t deviatio ns for the calculated value of t: +00,5 P. 2 ) d a , min = 1 d , d a, max = 1,05 d. For nuts, the countersink diameters, da, are specified in the relevant dimensional standards. 3 ) Spec ial designs (e.g . 90° or 60° coun ters ink) shall be indi cated on the drawing. A 60° counter sink is recommended for studs with thread run-out and for centre holes, and a parallel countersink is recommended for light alloy studs. 1 )
Figure 4: Dimensions of blind tapped holes with thread run-out (notation)
5 5 : 6 1 1 2 7 0 5 0 0 2 1 0 0 1 3 9 2 8 8 2 . r N f L 5 3 5 9 3 0 6 . r N d K H b m G s m e t s y S c o l b i b m o C G I S h t u e B d a o l n w o D n e m r o N
3.2.2 Blind tapped holes with thread undercut The dimensions of blind tapped holes with thread undercut shall be as given in fig ure 5 and table 2. Type C, with g1 and g 2 of normal design Type D, with g 1 and g 2 of short design
1 )
Key to figure b Useful thead length 1 )
Limi t deviatio n f or the calc ulated valu e o f t:
+0,5 0 P .
Other dimensions as in figure 4. Figure 5: Dimensions of blind tapped holes with thread undercut (notation)
Designation of a type C blind tapped hole with thread undercut:
Blind tapped hole DIN 76 – C
P ag e 5 DIN 76-1 : 2004-06 Table 2: Dimensions of thread run-outs and thread undercuts for internal threads
Thread pitch, P
Nominal diameter(s),
d
Thread run-out *) (guideline values)
e1
e3
dg
(coarse thread) Normal 1 )
0,2
5 5 : 6 1 1 2 7 0 5 0 0 2 1 0 0 1 3 9 2 8 8 2 . r N f L 5 3 5 9 3 0 6 . r N d K H b m G s m e t s y S c o l b i b m o C G I S h t u e B d a o l n w o D n e m r o N
e2
Thread undercut
–
Short 2 )
Long 3 )
1,3
0,8
2
0,25
1; 1,2
1,5
1
2,4
0,3
1,4
1,8
1,2
2,9
0,35
1,6; 1,7; 1,8
2,1
1,3
3,3
0,4
2; 2,3
2,3
1,5
3,7
0,45
2,2; 2,5; 2,6
2,6
1,6
4,1
0,5
3
2,8
1,8
4,5
0,6
3,5
3,4
2,1
5,4
0,7
4
3,8
2,4
6,1
0,75
4,5
4
2,5
6,4
0,8
5
4,2
2,7
6,8
1
6; 7
5,1
3,2
8,2
1,25
8
6,2
3,9
10
1,5
10
7,3
4,6
11,6
1,75
12
8,3
5,2
13,3
2
14; 16
9,3
5,8
14,8
2,5
18; 20; 22
11,2
7
17,9
3
24; 27
13,1
8,2
21
3,5
30; 33
15,2
9,5
24,3
4
36; 39
16,8
10,5
26,9
4,5
42; 45
18,4
11,5
29,4
5
48; 52
20,8
13
33,3
5,5
56; 60
22,4
14
35,8
6
64; 68
24
15
38,4
4 to 2,5 P
10 to 6,3 P
The dimensions specified are approximately equal to
6,3 to 4 P
H13
d + 0,1 d + 0,1 d + 0,1
g1
g1
Min. Type C Type D
Max. Type C Type D
(normal) 4 )
r
(short ) 5 ) (norma l) 4 ) (short ) 5 )
0,8
0,5
1,2
0,9
0,1
1
0,6
1,4
1
0,12
1,2
0,75
1,6
1,25
0,16
d + 0,2 d + 0,2 d + 0,2
1,4
0,9
1,9
1,4
0,16
1,6
1
2,2
1,6
0,2
1,8
1,1
2,4
1,7
0,2
d + 0,3 d + 0,3 d + 0,3
2
1,25
2,7
2
0,2
2,4
1,5
3,3
2,4
0,4
2,8
1,75
3,8
2,75
0,4
d + 0,3 d + 0,3 d + 0,5
3
1,9
4
2,9
0,4
3,2
2
4,2
3
0,4
4
2,5
5,2
3,7
0,6
d + 0,5 d + 0,5 d + 0,5
5
3,2
6,7
4,9
0,6
6
3,8
7,8
5,6
0,8
7
4,3
9,1
6,4
1
d + 0,5 d + 0,5 d + 0,5
8
5
10,3
7,3
1
10
6,3
13
9,3
1,2
12
7,5
15,2
10,7
1,6
d + 0,5 d + 0,5 d + 0,5
14
9
17,7
12,7
1,6
16
10
20
14
2
18
11
23
16
2
d + 0,5 d + 0,5 d + 0,5
20
12,5
26
18,5
2,5
22
14
28
20
3,2
24
15
30
21
3,2
–
4 P
2,5 P
–
–
0,5 P
*) Including blind hole extension. 1 )
e1 to be used where no other indications are made in product standards or on drawings.
2 )
e2 to be used where a short extension is required for technical reasons.
3 )
e3 to be used where a long extension is required for technical reasons.
4 )
Type C to be used w here no other i ndicat ions are mad e in p roduct stand ards o r on d rawings .
5 )
Type D to be used w here a short thread undercu t is requir ed for techni cal reas ons.
In the case of fine pitch threads, the dimensions of thread run-outs and thread undercuts shall be selected as a function of the pitch. NOTE 1: The dimensions of thread run-outs and thread undercuts for pipe threads are specified in DIN 76-2, and those for trapezoidal threads, buttress threads, knuckle threads and other coarse pitch threads are specified in DIN 76-3. NOTE 2: For other types of screw thread (e.g. UNF threads), it is recommended that the relationships between thread run-outs ( x or e values) and the pitch be used by analogy.
