The most complete conversion of metric, American and imperial threads between different threads in history

1 inch = 25.4 mm

Example: If you want to convert a US thread(american thread) with a diameter of 10 inches to a metric thread, we can simply multiply the diameter by 25.4, which is 10 × 25.4 = 254 mm; if we want to convert a metric thread with a diameter of 10 mm To make American threads, we only need to divide its diameter by 25.4, which is 10÷25.4=0.3937 inches

1. Metric thread specifications and corresponding pitch

单位: mm

序号	公称直径D，d			螺距
	第1系列	第2系列	第3系列	粗牙	细牙
1	1			0.25	0.2
2		1.1		0.25	0.2
3	1.2			0.25	0.2
4		1.4		0.3	0.2
5	1.6			0.35	0.2
6		1.8		0.35	0.2
7	2			0.4	0.25
8		2.2		0.45	0.25
9	3			0.45	0.35
10	3			0.5	0.35
11		3.5		0.6	0.35
12	4			0.7	0.5
13		4.5		0.75	0.5
14	5			0.8	0.5
15			5.5		0.5
16	6			1	0.75
17		7		1	0.75
18	8			1.25	1	0.75
19			9	1.25	1	0.75
20	10			1.5	1.25	1	0.75
21			11	1.5	1.5	1	0.75
22	12			1.75	1.25	1
23		14		2	1.5	1.25	1
24			15		1.5	1
25	16			2	1.5	1
26			17		1.5	1
27		18		2.5	2	1.5	1
28	20			2.5	2	1.5	1
29		22		2.5	2	1.5	1
30	24			3	2	1.5	1
31			25		2	1.5	1
32			26		2	1.5	1
33		27		3	2	1.5	1
34			28		2	1.5	1
35	30			3.5	3	2	1.5	1
36			32		3	2	1.5
37		33		3.5	3	2	1.5
38			35		3	2	1.5
39	36			4	3	2	1.5
40			38		3	2	1.5
41		39		4	3	2	1.5
42			40		3	2	1.5
43	42			4.5	4	3	2	1.5
44		45		4.5	4	3	2	1.5
45	48			5	4	3	2	1.5
46			50		3	2	1.5
47		52		5	4	3	2	1.5
48			55		4	3	2	1.5
49	56			5.5	4	3	2	1.5
50			58		4	3	2	1.5
51		60		5.5	4	3	2	1.5
52			62		4	3	2	1.5
53	64			6	4	3	2	1.5
54			65		4	3	2	1.5
55		68		6	4	3	2	1.5
56			70		6	4	3	2	1.5
57	72				6	4	3	2	1.5
58			75		4	3	2	1.5
59		76			6	4	3	2	1.5
60			78		2
61	80				6	4	3	2	1.5
62			82		2
63		85			6	4	3	2
64	90				6	4	3	2
65		95			6	4	3	2
66	100				6	4	3	2
67		105			6	4	3	2
68	110				6	4	3	2
69		115			6	4	3	2
70		120			6	4	3	2
71	125				8	6	4	3	2
72		130			8	6	4	3	2
73			135		6	4	3	2
74	140				8	6	4	3	2
75			145		6	4	3	2
76		150			8	6	4	3	2
77			155			6	4	3
78	160				8	6	4	3
79			165			6	4	3
80		170			8	6	4	3
81			175			6	4	3
82	180				8	6	4	3
83			185			6	4	3
84		190			8	6	4	3
85			195			6	4	3
86	200				8	6	4	3
87			205			6	4	3
88		210			8	6	4	3
89			215			6	4	3
90	220				8	6	4	3
91			225			6	4	3
92			230		8	6	4	3
93			235			6	4	3
94		240			8	6	4	3
95			245			6	4	3
96	250				8	6	4	3
97			255			6	4
98		260			8	6	4
99			265			6	4
100			270		8	6	4
101			275			6	4
102	280				8	6	4
103			285			6	4
104			290		8	6	4
105			295			6	4
106		300			8	6	4

The first series of diameters is preferred, followed by the second series of diameters and finally the third series of diameters.

Refer to GB/T 193-2003 Ordinary thread diameter and pitch series

2. American thread specifications and corresponding number of teeth

单位: inch

 

序号	公称直径D，d	大径D	粗牙UNC	细牙UNF	超细牙UNEF
1	#0	0.06		80
2	#1	0.073	64	72
3	#2	0.086	56	64
4	#3	0. 099	48	56
5	#4	0.112	40	48
6	#5	0.125	40	44
7	#6	0.138	32	40
8	#8	0.164	32	36
9	#10	0.19	24	32
10	#12	0.216	24	28	32
11	1/4	0.25	20	28	32
12	5/16	0.3125	18	24	32
13	3/8	0.375	16	24	32
14	7/16	0.4375	14	20	28
15	1/2	0.5	13	20	28
16	9/16	0.5625	12	18	24
17	5/8	0.625	11	18	24
18	11/16	0.6875			24
19	3/4	0.75	10	16	20
20	13/16	0.8125			20
21	7/8	0.875	9	14	20
22	15/16	0.9375			20
23	1	1	8	12	20
24	1-1/16	1.0625			18
25	1-1/8	1.125	7	12	18
26	1-3/16	1.1875			18
27	1-1/4	1.25	7	12	18
28	1-5/16	1.3125			18
29	1-3/8	1.375	6	12	18
30	1-7/16	1.4375			18
31	1-1/2	1.5	6	12	18
32	1-9/16	1.5625			18
33	1-5/8	1.625			18
34	1-11/16	1.6875			18
35	1-3/4	1.75	5
36	1-13/16	1.8125
37	1-7/8	1.875
38	1-15/16	1.9375
39	2	2	4.5
40	2-1/8	2.125
41	2-1/4	2.25	4.5
42	2-3/8	2.375
43	2-1/2	2.5	4
44	2-5/8	2.625
45	2-3/4	2.75	4
46	2-7/8	2.875
47	3	3	4
48	3-1/8	3.125
49	3-1/4	3.25	4
50	3-3/8	3.375
51	3-1/2	3.5	4
52	3-5/8	3.625
53	3-3/4	3.75	4
54	3-7/8	3.875
55	4	4	4
56	4-1/8	4.125
57	4-1/4	4.25
58	4-3/8	4.375
59	4-1/2	4.5
60	4-5/8	4.625
61	4-3/4	4.75
62	4-7/8	4.875
63	5	5
64	5-1/8	5.125
65	5-1/4	5.25
66	5-3/8	5.375
67	5-1/2	5.5
68	5-5/8	5.625
69	5-3/4	5.75
70	5-7/8	5.875
71	6	6

Refer to ASME B1.1-2003 unified inch thread

3. Inch thread specifications and corresponding number of teeth

单位：inch

序号	直径D	牙数P	细牙P	大径D
1	1/8	40		0.125
2	3/16	24	32	0.1875
3	7/32		28	0.2188
4	1/4	20	26	0.25
5	9/32		26	0.2812
6	5/16	18	22	0.3125
7	3/8	16	20	0.375
8	7/16	14	18	0.4375
9	1/2	12	16	0.5
10	9/16	12	16	0.5625
11	5/8	11	14	0.625
12	11/16	11	14	06875
13	3/4	10	12	0.75
14	7/8	9	11	0.875
15	1	8	10	1
16	1-1/8	7	9	1.125
17	1-1/4	7	9	1.25
18	1-3/8		8	1.375
19	1-1/2	6	8	1.5
20	1-5/8		8	1.625
21	1-3/4	5	7	1.75
22	2	4.5	7	2
23	2-1/4	4	6	2.25
24	2-1/2	4	6	2.5
25	2-3/4	35	6	2.75
26	3	3.5	5	3
27	3-1/4	3.25		3.25
28	3-1/2	3.25		3.5
29	3-3/4	3		3.75
30	4	3		4
31	4-1/2	2.875		4.5
32	5	2.75		5
33	5-1/2	2.625		5.5
34	6	2.5		6

Parallel threads to BS 84-2007 Whitworth thread style