Outside diameter tolerances for bolt threads

Guide lines for blank preparation and thread cutting

		4h			6g for thread dia. above 1,4mm 6h for thread dia up to 1,4mm			6e
Nominal thread Ø (mm)	Pitch (mm)	Min. dia. (mm)	Max. dia. (mm)	Turning dia. targ. val. (mm)	Min. dia. (mm)	Max. dia. (mm)	Turning dia. targ. val. (mm)	Min. dia. (mm)	Max. dia. (mm)	Turning dia. targ. val. (mm)
1	0,25	0,958	1,0	0,98	0,933	1,000	0,97	0,888	0,955	0,92
1,1	0,25	1,058	1,1	1,08	1,033	1,100	1,07	0,988	1,055	1,02
1,2	0,25	1,158	1,2	1,18	1,133	1,200	1,17	1,088	1,155	1,12
1,4	0,3	1,352	1,4	1,38	1,325	1,400	1,36	1,279	1,354	1,31
1,6	0,35	1,547	1,6	1,57	1,496	1,581	1,54	1,469	1,544	1,51
1,8	0,35	1,747	1,8	1,77	1,696	1,781	1,74	1,669	1,754	1,71
2	0,4	1,94	2,0	1,97	1,886	1,981	1,94	1,857	1,952	1,90
2,2	0,45	2,137	2,2	2,16	2,080	2,180	2,13	2,052	2,152	2,10
2,5	0,45	2,437	2,5	2,46	2,380	2,480	2,43	2,352	2,452	2,40
3	0,5	2,933	3,0	2,96	2,874	2,980	2,92	2,844	2,950	2,89
3,5	0,6	3,42	3,5	3,46	3,354	3,479	3,41	3,322	3,447	3,38
4	0,7	3,91	4,0	3,95	3,838	3,978	3,91	3,804	2,944	3,87
4,5	0,75	4,41	4,5	4,45	4,338	4,478	4,41	4,304	4,444	4,37
5	0,8	4,905	5,0	4,95	4,826	4,976	4,90	4,790	4,940	4,86
6	1	5,888	6,0	5,94	5,794	5,974	5,88	5,760	5,940	5,85
7	1	6,888	7,0	6,94	6,794	6,974	6,88	6,760	6,940	6,85
8	1,25	7,868	8,0	7,93	7,760	7,972	7,87	7,725	7,937	7,83
10	1,5	9,85	10,0	9,92	9,732	9,968	9,85	9,697	9,933	9,81
12	1,75	11,83	12,0	11,92	11,701	11,966	11,83	11,664	11,929	11,80
14	2	13,82	14,0	13,91	13,682	13,962	13,82	13,649	13,929	13,79
16	2	15,82	16,0	15,91	15,682	15,962	15,82	15,649	15,929	15,79
18	2,5	17,788	18,0	17,89	17,623	17,958	17,79	17,585	17,920	17,75
20	2,5	19,788	20,0	19,89	19,623	19,958	19,79	19,585	19,920	19,75
22	2,5	21,788	22,0	21,89	21,623	21,958	21,79	21,585	21,920	21,75
24	3	23,764	24,0	23,88	23,577	23,952	23,77	23,540	23,915	23,73
27	3	26,764	27,0	26,88	26,577	26,952	26,77	26,540	26,915	26,73
30	3,5	29,735	30,0	29,87	29,522	29,947	29,73	29,485	29,910	29,70

Whitworth pipe thread DIN ISO 228, tolerance class A
Thread	tpi	Min. dia. (mm)	Max. dia. (mm)	Turning dia. target val. (mm)
G 1/16"	28	7,509	7,723	7,62
G 1/8"	28	9,514	9,728	9,62
G 1/4"	19	12,907	13,157	13,03
G 3/8"	19	16,412	16,662	16,54
G 1/2"	14	20,671	20,955	20,81
G 5/8"	14	22,627	22,911	22,77
G 3/4"	14	26,157	26,441	26,30
G 7/8"	14	29,917	30,201	30,06
G 1"	11	32,889	33,249	33,07
G 1 1/8"	11	37,537	37,897	37,72
G 1 1/4"	11	41,550	41,910	41,73
G 1 3/8"	11	43,960	44,320	44,14
G 1 1/2"	11	47,443	47,803	47,62
G 1 3/4"	11	53,386	53,746	53,57
G 2"	11	59,254	59,614	59,43
G 2 1/4"	11	65,276	65,710	65,49
G 2 1/2"	11	74,750	75,184	74,97
G 2 3/4"	11	81,100	81,534	81,32
G 3"	11	87,450	87,884	87,67
G 3 1/2"	11	99,896	100,330	100,11
G 4"	11	112,596	113,030	112,81

technical drawing of a bolt roughing diameter

Tapered Whitworth pipe thread, taper 1:16
Thread	tpi	Do Min. dia. (mm)	Do Max. dia. (mm)	Do Turning dia. target val. (mm)	L target value (mm)
R 1/8"	28	9,422	9,534	9,48	8,2
R 1/4"	19	12,700	12,863	12,78	12,1
R 3/8"	19	16,181	16,343	16,26	12,5
R 1/2"	14	20,330	20,555	20,44	16,4
R 3/4"	14	25,735	25,960	25,85	17,7
R 1"	11	32,455	32,743	32,60	20,9
R 1 1/4"	11	40,973	41,260	41,12	23,2
R 1 1/2"	11	46,866	47,153	47,01	23,2
R 2"	11	58,477	58,764	58,62	27,5

technical drawing of a taper pin roughing diameter

		NPT				NPTF
Thread	tpi	Do Min. dia. (mm)	Do Max. dia. (mm)	Do Turning dia. target val. (mm)	L target value (mm)	Do Min. dia. (mm)	Do Max. dia. (mm)	Do Turning dia. target val. (mm)	L target value (mm)
1/16"	27	7,521	7,643	7,58	8,4	7,525	7,617	7,57	8,4
1/8"	27	9,866	9,988	9,93	8,5	9,870	9,962	9,92	8,5
1/4"	18	13,099	13,255	13,18	12,7	13,129	13,215	13,17	12,7
3/8"	18	16,518	16,674	16,60	12,9	16,548	16,634	16,59	12,9
1/2"	14	20,551	20,713	20,63	16,8	20,617	20,703	20,66	16,8
3/4"	14	25,866	26,028	25,95	17,1	25,932	26,018	25,98	17,1
1"	11 1/2	32,419	32,591	32,51	21,3	32,475	32,561	32,52	21,3
1 1/4"	11 1/2	41,144	41,316	41,23	21,9	41,200	41,286	41,24	21,9
1 1/2"	11 1/2	47,214	47,386	47,30	22,3	47,270	47,356	47,31	22,3
2"	11 1/2	59,226	59,398	59,31	23,1	59,282	59,368	59,33	23,1

UNC and UNF blank diameter tolerances for external threads

Guide lines for blank preparation and thread cutting

Tolerance class 2A

(excerpt from ANSI B 1.1)

	UNC				UNF
Thread	tpi	Min. dia. (mm)	Max. dia. (mm)	Turning dia. target val. (mm)	tpi	Min. dia. (mm)	Max. dia. (mm)	Turning dia. target val. (mm)
No. 0					80	1,430	1,511	1,47
No. 1	64	1,742	1,839	1,79	72	1,750	1,839	1,79
No. 2	56	2,065	2,169	2,12	64	2,072	2,169	2,12
No. 3	48	2,383	2,497	2,44	56	2,393	2,497	2,44
No .4	40	2,695	2,825	2,76	48	2,713	2,827	2,77
No .5	40	3,025	3,155	3,09	44	3,035	3,157	3,10
No. 6	32	3,333	3,485	3,41	40	3,355	3,485	3,42
No. 8	32	3,991	4,143	4,07	36	4,006	4,146	4,08
No. 10	24	4,618	4,801	4,71	32	4,651	4,803	4,73
No .12	24	5,278	5,461	5,37	28	5,296	5,461	5,38
1/4"	20	6,116	6,322	6,22	28	6,160	6,325	6,24
5/16"	18	7,687	7,908	7,80	24	7,727	7,910	7,82
3/8"	16	9,253	9,492	9,37	24	9,314	9,497	9,41
7/16"	14	10,814	11,076	10,95	20	10,873	11,079	10,98
1/2"	13	12,385	12,662	12,52	20	12,461	12,667	12,56
9/16"	12	13,957	14,247	14,10	18	14,031	14,252	14,14
5/8"	11	15,527	15,834	15,68	18	15,618	15,839	15,73
3/4"	10	18,676	19,004	18,84	16	18,773	19,012	18,89
7/8"	9	21,824	22,177	22,00	14	21,922	22,184	22,05
1"	8	24,968	25,349	25,16	12	25,064	25,354	25,21
1 1/8"	7	28,102	28,519	28,31	12	28,239	28,529	28,38
1 1/4"	7	31,277	31,694	31,49	12	31,414	31,704	31,56