Technical drawing of the thread cross-section 30 degree flank angle round thread

Round Thread DIN 405

The round thread according to DIN 405 is a round thread for general use. Round threads are characterized by their unique profile. The rounded shape completely omits sharp edges, making the round thread according to DIN 405 less susceptible to dirt and wear, significantly reducing maintenance and cleaning effort. Accordingly, DIN 405 round threads are used in so-called rough work environments where dirt and high mechanical loads are part of everyday life, such as on railway wagons, fire trucks, or in mining.

Besides the round thread DIN 405, there are other types of round threads, each with specific application areas. However, the round thread DIN 405 is the most common standard in rough work environments without additional special conditions.

The round thread DIN 405 has a flank angle of 30°. The external diameter is given in mm, and the pitch in inches.

The thread designation is composed of the abbreviation Rd, the nominal diameter, and the pitch, where the number of threads per inch is expressed as a fraction. An example would be Rd 12 x 1/10”.

The round thread DIN 405 has different nominal profiles for external and internal threads. This is also reflected in the thread table for the round thread DIN 405. Here, both the external diameter and the bolt diameter in mm are listed. The pitch can be read from the table below in threads per inch or converted into mm. The core hole diameter required for cutting a round thread DIN 405 is also listed. The appropriate dies and taps for round thread DIN 405 can be found in our shop; simply click on the corresponding link in the table!

To the overview thread standards
Thread Identifier Zoll
Diameter outside mm
Diameter Core hole mm
Diameter Bolt mm
Gears per Inch
Pitch mm
Taps in our online-shop
Dies in our online-shop
Rd 8 x 1/10”
8,254
5,714
5,460
10
2,540
Rd 9 x 1/10”
9,254
6,714
6,460
10
2,540
Rd 10 x 1/10”
10,254
7,714
7,460
10
2,540
Rd 11 x 1/10”
11,254
8,714
8,460
10
2,540
Rd 12 x 1/10”
12,254
9,714
9,460
10
2,540
Rd 14 x 1/8”
14,318
11,142
10,825
8
3,175
Rd 16 x 1/8”
16,318
13,142
12,825
8
3,175
Rd 18 x 1/8”
18,318
15,142
14,825
8
3,175
Rd 20 x 1/8”
20,318
17,142
16,825
8
3,175
Rd 22 x 1/8”
22,318
19,142
18,825
8
3,175
Rd 24 x 1/8”
24,318
21,142
20,825
8
3,175
Rd 28 x 1/8”
28,318
25,142
24,825
8
3,175
Rd 30 x 1/8”
30,318
27,142
26,825
8
3,175
Rd 32 x 1/8”
32,818
29,142
28,825
8
3,175
Rd 34 x 1/8”
34,318
31,142
30,825
8
3,175
Rd 36 x 1/8”
36,318
33,142
32,825
8
3,175
Rd 38 x 1/8”
38,318
35,142
34,825
8
3,175
Rd 40 x 1/6”
40,423
36,190
35,767
6
4,233
Rd 42 x 1/6”
42,423
38,190
37,767
6
4,233
Rd 44 x 1/6”
44,423
40,190
39,767
6
4,233
Rd 46 x 1/6”
46,423
42,190
41,767
6
4,233
Rd 48 x 1/6”
48,423
44,190
43,767
6
4,233
Rd 50 x 1/6”
50,423
46,190
45,767
6
4,233
Rd 52 x 1/6”
52,423
48,100
47,767
6
4,233
Rd 55 x 1/6”
55,423
51,190
50,767
6
4,233
Rd 58 x 1/6”
58,423
54,190
53,767
6
4,233
Rd 60 x 1/6”
60,423
56,190
55,767
6
4,233
Rd 62 x 1/6”
62,423
58,190
57,767
6
4,233
Rd 65 x 1/6”
65,423
61,190
60,767
6
4,233
Rd 68 x 1/6”
68,423
64,190
63,767
6
4,233
Rd 70 x 1/6”
70,423
66,190
65,767
6
4,233
Rd 72 x 1/6”
72,423
68,190
67,767
6
4,233
Rd 75 x 1/6”
75,423
71,190
70,767
6
4,233
Rd 78 x 1/6”
78,423
74,190
73,767
6
4,233
Rd 80 x 1/6”
80,423
76,190
75,767
6
4,233
Rd 82 x 1/6”
82,423
78,190
77,767
6
4,233
Rd 85 x 1/6”
85,423
81,190
80,767
6
4,233
Rd 88 x 1/6”
88,423
84,190
83,767
6
4,233
Rd 90 x 1/6”
90,423
86,190
85,767
6
4,233
Rd 92 x 1/6”
92,423
88,190
87,767
6
4,233
Rd 95 x 1/6”
95,423
91,190
90,767
6
4,233
Rd 98 x 1/6”
98,423
94,190
93,767
6
4,233
Rd 100 x 1/6”
100,423
96,190
95,767
6
4,233
Rd 105 x 1/4”
105,635
99,285
98,650
4
6,350
Rd 110 x 1/4”
110,635
104,285
103,650
4
6,350
Rd 115 x 1/4”
115,635
109,285
108,650
4
6,350
Rd 120 x 1/4”
120,635
114,285
113,650
4
6,350
Rd 125 x 1/4”
125,635
119,285
118,650
4
6,350
Rd 130 x 1/4”
130,635
124,285
123,650
4
6,350
Rd 135 x 1/4”
135,635
129,285
128,650
4
6,350
Rd 140 x 1/4”
140,635
134,285
133,650
4
6,350
Rd 145 x 1/4”
145,635
139,285
138,650
4
6,350
Rd 150 x 1/4”
150,635
144,285
143,650
4
6,350
Rd 155 x 1/4”
155,635
149,285
148,650
4
6,350
Rd 160 x 1/4”
160,635
154,285
153,650
4
6,350
Rd 165 x 1/4”
165,635
159,285
158,650
4
6,350
Rd 170 x 1/4”
170,635
164,285
163,650
4
6,350
Rd 175 x 1/4”
175,635
169,285
168,650
4
6,350
Rd 180 x 1/4”
180,635
174,285
173,650
4
6,350
Rd 185 x 1/4”
185,635
179,285
178,650
4
6,350
Rd 190 x 1/4”
190,635
184,285
183,650
4
6,350
Rd 195 x 1/4”
195,635
189,285
188,650
4
6,350
Rd 200 x 1/4”
200,635
194,285
193,650
4
6,350