Legacy BS 3643 / ISO 965 Thread Tolerance Data

The legacy tolerance-system dataset behind general-purpose metric threads: profile geometry constants per pitch, ISO 261 diameter/pitch grid, tolerance class matrices by engagement length, fundamental deviations per pitch, pitch/major/minor tolerance widths per grade, engagement-length groups and two fully worked limit calculations — in the source's decimal-comma notation with its own quirks flagged.

Last updated: 2026-11

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Legacy BS 3643 / ISO 965 Thread Tolerance Data in an industrial setting — Illustrative image redrawn from real product references — not a photograph of stocked items.

Specifications

Where the BS 3643 limits ladder gives the answer, this collected page gives the machinery that produces it — the tolerance system itself as the legacy reference tabulated it. The grids run from profile geometry (the H-fraction constants per pitch: 0,86603P full height, 0,54127P at 5/8H, down to the H/8 crest band, plus a 26-pitch numeric table from 0,2 to 8) through the ISO 261 diameter/pitch combinations grid, the class-selection matrices (female G/H positions and male e/f/g/h positions crossed with Fine/Medium/Rough classes and Short/Normal/Long engagement — e.g. medium female threads take 5G/6G/7G at G or 5H/6H/7H at H), fundamental deviations per pitch (the es for g ladder: −20 at 0,5 up to −81 at 6,0 µm, with the e/f/h companions in the paired grid), and the tolerance widths per grade (T d2/T D2 multipliers 0,50 at grade 3 to 2,00 at grade 9 relative to grade 6; the per-pitch grade-6 widths and the male-major/female-minor tables). Two worked examples close the set — M30 x 3,5 - 6g and M12 x 1,25 - 4h externally, M30 x 3,5 - 6H, M12 x 1,25 - 7H, M150 x 4 - 6G and M200 x 6 internally — each carried from basic diameter through fundamental deviation, tolerance widths and the resulting max/min limits. Carried verbatim with flagged quirks: a "60" printed for 600 in one external-T:8 cell, swapped d min/d max identity labels in the external worked example, and the doubled pitch marker "M200 x 6 x 5H" in the internal example — read with the flags in mind. Class-specific limits of size are on the companion BS 3643 ladder page in this family; modern-edition ISO 965 data is on the ISO 965 reference page.

Profile geometry	H-fraction constants per pitch (0,86603P / 0,54127P / 0,32476P / H/4 / H/8 / H/6) + numeric table P 0,2 - 8
Class matrices	Female G/H and male e/f/g/h positions × Fine/Medium/Rough × Short/Normal/Long engagement, as printed
Deviations	EI (G, H) and es (e, f, g, h) per pitch 0,2 - 8,0 µm; es-for-g formula ladder −20 to −81 µm
Tolerance widths	Grade multipliers 0,50 - 2,00 vs grade 6; grade-6 T d2/T D2 ladder M3 - M64; male-major/female-minor widths per pitch
Engagement groups	Short/Normal/Long boundaries by major-dia range (0,99 - 300 mm) and pitch
Not tabulated	Limits for classes beyond the worked examples (use the BS 3643 ladder page for 6g/6H), strength values, torque — per RFQ

Standards index (legacy BS 3643 / ISO 965 editions)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Standard	Legacy use on this page
BS 3643-1:2007	ISO metric screw threads – principles and basic data used by the original RoyMech reference.
BS 3643-2:2007	Selected limits of size used by the original RoyMech reference.
BS ISO 965-1:1998	Earlier ISO metric thread tolerance principles and basic data.
BS ISO 965-2:1998	Earlier limits of size for general-purpose internal and external metric threads.
BS ISO 261:1998	General plan for ISO general-purpose metric screw threads.

Row 2 (BS 3643-2:2007): H/6 pitch formula prints "0,144337P" (six decimals vs five elsewhere) — as printed

Thread profile geometry — H fractions per pitchAs printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
	H	5/8H	3/8H	H/4	H/8	H/6
Pitch	0,86603P	0,54127P	0,32476P	0,21651P	0,10825P	0,144337P
mm	mm	mm	mm	mm	mm	mm
0,2	0,17320508	0,10825318	0,0649519	0,04330128	0,02165064	0,02886752
0,25	0,21650635	0,13531648	0,08118988	0,0541266	0,0270633	0,0360844
0,3	0,25980762	0,16237977	0,09742785	0,06495192	0,03247595	0,04330127
0,35	0,30310889	0,18944307	0,11366583	0,07577724	0,03788861	0,05051815
0,4	0,34641016	0,21650636	0,1299038	0,08660256	0,04330127	0,05773503
0,45	0,38971143	0,24356966	0,14614178	0,09742788	0,04871393	0,0649519
0,5	0,4330127	0,27063295	0,16237975	0,1082532	0,05412659	0,07216878
0,6	0,51961524	0,32475954	0,1948557	0,12990384	0,06495191	0,08660253
0,7	0,60621778	0,37888613	0,22733165	0,15155448	0,07577723	0,1010363
0,75	0,64951905	0,40594943	0,24356963	0,1623798	0,08118989	0,10825318
0,8	0,69282032	0,43301272	0,2598076	0,17320512	0,08660254	0,11547005
1	0,8660254	0,5412659	0,3247595	0,2165064	0,10825318	0,14433757
1,25	1,08253175	0,67658238	0,40594938	0,270633	0,13531648	0,18042197
1,5	1,2990381	0,81189885	0,48713925	0,3247596	0,16237977	0,21650635
1,75	1,51554445	0,94721533	0,56832913	0,3788862	0,18944307	0,25259075
2	1,7320508	1,0825318	0,649519	0,4330128	0,21650636	0,28867513
2,5	2,1650635	1,35316475	0,81189875	0,541266	0,27063295	0,36084392
3	2,5980762	1,6237977	0,9742785	0,6495192	0,32475954	0,4330127
3,5	3,0310889	1,89443065	1,13665825	0,7577724	0,37888613	0,50518148
4	3,4641016	2,1650636	1,299038	0,8660256	0,43301272	0,57735027
4,5	3,8971143	2,43569655	1,46141775	0,9742788	0,48713931	0,64951905
5	4,330127	2,7063295	1,6237975	1,082532	0,5412659	0,72168783
5,5	4,7631397	2,97696245	1,78617725	1,1907852	0,59539249	0,79385662
6	5,1961524	3,2475954	1,948557	1,2990384	0,64951908	0,8660254
8	6,9282032	4,3301272	2,598076	1,7320512	0,86602544	1,15470053

Basic thread dims — coarse series (M3 - M36, paired columns)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Thread	Pitch	Major	Pitch Dia	Minor	Thread	Pitch	Major	Pitch Dia	Minor
	P	D/d	D 2 /d 2	D 1 /d 1		P	D/d	D 2 /d 2	D 1 /d 1
	mm	mm	mm	mm		mm	mm	mm	mm
M3 x 0,5	0,5	3,000	2,675	2,459	M12x1,75	1,7	12,000	10,863	10,106
M4 x 0,7	0,7	4,000	3,545	3,242	M16 x 2,0	2	16,000	14,701	13,835
M5 x 0,8	0,8	5,000	4,48	4,134	M20 x2,5	2,5	20,000	18,376	17,294
M6 x 1,0	1	6,000	5,35	4,917	M24 x 3,0	3	24,000	22,051	20,752
M8 x 1,25	1,25	8,000	7,188	6,647	M30 x 3,5	3,5	30,000	27,727	26,211
M10 x 1,5	1,5	10,000	9,026	8,376	M36 x 4,0	4	36,000	33,402	31,67

ISO 261 diameter/pitch combinations gridAs printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
M1 x 0,25	M1,2 x 0,25	M1,4 x 0,30	M1,6 x 0,35	M1,8 x 0,35	M2 x 0,4	M2,2 x 0,45
M2,5 x 0,45	M2,5 x 0,45	M3 x 0,5	M3,5 x 0,6	M4 x 0,7	M4,5 x 0,75	M5 x 0,8
M6 x 1	M7 x 1	M8 x1,25	M9 x1,25	M10 x 1,5	M11 x 1,5	M12 x 1,75
M14 x 2,0	M16 x 2	M18 x 2,5	M20 x 2,5	M22 x 2,5	M24 x 3,0	M27 x 3
M30 x 3,5	M33 x 3,5	M36 x 4	M39 x 4	M42 x 4,5	M45 x 5	M48 x5
M52 x 5	M56 x5,5	M60 x 5,5	M64 x 6	M68 x 6

Female thread tolerance classes — positions G/H by engagement lengthAs printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Female Threads
Class v	Tolerance Position G			Tolerance Position H
	Short	Normal	Long	Short	Normal	long
Fine	-	-	-	4H	5H	6H
Medium	5G	6G	7G	5H	6H	7H
Rough	-	7G	8G	-	7H	8H

Male thread tolerance classes — positions e/f/g/h by engagement lengthAs printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Male Threads
Class v	Tolerance Position e			Tolerance Position f			Tolerance Position g			Tolerance Position h
	Short	Normal	Long	Short	Normal	Long	Short	Normal	Long	Short	Normal	Long
Fine										3h4h	4h	5h4h
Medium		6e	7e6e		6f		5g6g	6g	7g6g	5h6h	6h	7h6h
Rough								8g	9g8g

Length of thread engagement groups (over/up-to by major dia and pitch)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Basic Major Dia		Pitch	Length of Thread Engagement
			Short	Normal		Long
over	Up to +(inc)		Up to + (Inc)	Over	Up to + (Inc)	Over
mm	mm	mm	mm	mm	mm	mm
0,99	1,4	0,2	0,5	0,5	1,4	1,4
		0,25	0,6	0,6	1,7	1,7
		0,3	0,7	0,7	2,0	2,0
1,4	2,8	0,2	0,5	0,5	1,5	1,5
		0,25	0,6	0,6	1,9	1,9
		0,35	0,8	0,8	2,6	2,6
		0,4	1,0	1,0	3,0	3,0
		0,45	1,3	1,3	3,8	3,8
2,8	5,6	0,35	1,0	1,0	3,0	3,0
		0,5	1,5	1,5	4,5	4,5
		0,6	1,7	1,7	5,0	5,0
		0,7	2	2	6	6
		0,75	2,2	2,2	6,7	6,7
		0,8	2,5	2,5	7,5	7,5
5,6	11,2	0,75	2,4	2,4	7,1	7,1
		1,0	3	3	9	9
		1,25	4	4	12	12
		1,5	5	5	15	15
11,2	22,4	1,0	3,8	3,8	11	11
		1,25	4,5	4,5	13	13
		1,5	5,6	5,6	16	16
		1,75	6	6	18	18
		2,0	8	8	24	24
		2,5	10	10	30	30
22,4	45,0	1,0	4	4	12	12
		1,5	6,3	6,3	19	19
		2,0	8,5	8,5	25	25
		3,0	12	12	36	36
		3,5	15	15	45	45
		4,0	18	18	53	53
		4,5	21	21	63	63
45,0	90,0	1,5	7,5	7,5	22	22
		2,0	9,5	9,5	28	28
		3,0	15	15	45	45
		4,0	19	19	56	56
		5,0	24	24	71	71
		5,5	28	28	85	85
		6,0	32	32	95	95
90,0	180,0	2,0	12	12	36	36
		3,0	18	18	53	53
		4,0	24	24	71	71
		6,0	36	36	106	106
180,0	300	3,0	20	20	60	60
		4,0	26	26	80	80
		5,0	40	40	118	118

Fundamental deviations EI/es per pitch (paired columns)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Pitch	Female Thread D 2 ,D 1		Male Thread d,d 2				Pitch	Female Thread D 2 ,D 1		Male Thread d,d 2
	EI		es					EI		es
	G	H	e	f	g	h		G	H	e	f	g	h
mm	μ m	μ m	μ m	μ m	μ m	μ m	mm	μ m	μ m	μ m	μ m	μ m	μ m
0,2	+17	0	-	-	-17	0	1,25	+28	0	-63	-42	-28	0
0,25	+18	0	-	-	-18	0	1,5	+32	0	-67	-45	-32	0
0,3	+18	0	-	-	-18	0	1,75	+34	0	-71	-48	-34	0
0,35	+19	0	-	-34	-19	0	2,0	+38	0	-71	-52	-38	0
0,4	+19	0	-	-34	-19	0	2,5	+42	0	-80	-58	-42	0
0,45	+20	0	-	-35	-20	0	3,0	+48	0	-85	-63	-48	0
0,5	+20	0	-50	-36	-20	0	3,5	+53	0	-90	-70	-53	0
0,6	+21	0	-53	-36	-21	0	4,0	+60	0	-95	-75	-60	0
0,7	+22	0	-56	-38	-22	0	4,5	+63	0	-100	-80	-63	0
0,75	+22	0	-56	-38	-22	0	5,0	+71	0	-106	-85	-71	0
0,8	+24	0	-60	-38	-24	0	5,5	+75	0	-112	-90	-75	0
1,0	+26	0	-60	-40	-26	0	6,0	+80	0	-118	-95	-80	0
							8,0	+100	0	-140	-118	-100	0

Pitch diameter tolerances T d2 / T D2 per grade (over/to ladder)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
D2 /d2		Pitch	Pitch Diameter of internal threads					Pitch diameter of external threads
Over	To(&inc)		T:4	T:5	T:6	T:7	T:8	T:3	T:4	T:5	T:6	T:7	T:8	T:9
mm	mm	mm	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m
0,99	1,4	0,2	40	-	-			24	30	48	48
		0,25	45	56	-			25	34	42	53
		0,3	48	60	75			28	36	45	56
1,4	2,8	0,2	42					25	32	40	50
		0,25	48	60				28	36	45	56
		0,35	53	67	85			32	40	50	63	80
		0,4	56	71	90			34	42	53	67	85
		0,45	60	75	95			36	45	56	71	90
2,8	5,6	0,35	56	71	90			34	52	53	67	85
		0,5	63	80	100	125		38	48	60	75	95
		0,6	71	90	112	140		42	53	67	85	106
		0,7	75	95	118	150		45	56	71	90	112
		0,75	75	95	118	150		45	56	71	90	112
		0,8	80	100	125	160	200	48	60	75	95	118	150	90
5.6	11,2	0,75	85	106	132	170		50	63	80	100	125
		1	95	118	140	190	236	56	71	90	112	140	180	224
		1,25	100	125	160	200	250	60	75	95	118	150	189	235
		1,5	112	140	180	224	280	67	85	106	132	170	212	265
11,2	22,4	1	100	125	160	200	250	60	75	95	118	150	190	235
		1,25	112	140	180	224	280	67	85	106	132	170	212	265
		1,4	118	150	190	236	300	71	90	112	140	180	224	280
		1,75	125	160	200	250	315	75	95	118	150	190	236	300
		2,0	132	170	212	265	335	80	100	125	160	200	250	315
		2,5	140	180	224	280	355	85	106	132	170	212	265	335
22,4	45	1	106	132	170	212		63	80	100	125	160	200	250
		1,5	125	160	200	250	315	75	95	118	150	190	236	300
		2	140	180	224	280	355	85	106	132	170	212	265	335
		3	170	212	265	335	425	100	125	160	200	250	315	400
		3,5	180	224	280	355	450	106	132	170	212	265	335	425
		4	190	236	300	375	475	112	140	180	224	280	355	450
		4,5	200	250	315	400	500	118	150	190	236	300	375	475
45	90	1,5	132	170	212	265	335	80	100	125	160	200	250	315
		2	150	190	236	300	375	90	112	140	180	224	280	355
		3	180	224	280	355	450	106	132	170	212	265	335	425
		4	200	250	315	400	500	118	150	190	236	300	375	475
		5	212	265	335	425	530	125	160	200	250	315	400	500
		5,5	224	280	355	450	560	132	170	212	265	335	425	530
		6	236	300	375	475	600	140	180	224	280	355	450	560
90	180	2	160	200	250	315	400	95	118	150	190	236	300	375
		3	190	236	300	375	475	112	140	180	224	280	355	450
		4	212	265	335	425	530	125	160	200	250	315	400	500
		6	250	315	400	500	630	150	190	236	300	375	475	600
		8	280	355	450	560	710	175	212	265	335	425	530	670
180	355	3	212	265	335	425	530	125	160	200	250	315	400	500
		4	236	300	375	475	60	140	180	224	280	355	450	560
		6	265	335	425	530	670	160	200	250	315	400	500	630
		8	300	375	475	600	750	180	224	280	355	450	560	710
Over	To(&inc)	Pitch	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m	μ m
D2 /d2			T:4	T:5	T:6	T:7	T:8	T:3	T:4	T:5	T:6	T:7	T:8	T:9
			Pitch Diameter of internal threads					Pitch diameter of external threads

Row 16 (): row 0,8 external T:9 prints "90" after "150" — the source's own column order, carried verbatim (no other T:9 value appears on this row group)
Row 16 (): row 0,8 internal T:8 prints "200" while rows above leave T:7/T:8 blank — grade availability varies by row as printed
Row 17 (5.6): dia range prints "5.6" with a decimal point amid the page's decimal-comma convention — as printed
Row 47 (): 180-355 row, internal T:8 prints "60" (pattern-consistent value would be 600) — as printed, flagged not corrected

Major (male) / minor (female) diameter tolerances per pitchAs printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Pitch	Major Dia -Male threads			Minor Diameter - Female Threads
	T:4	T:6	T:8	T:4	T:5	T:6	T:7	T:8
mm	μ m	μ m	μ m	μ m	μ m	μ m	μ m;	μ m
0,2	36	56		38
0,25	42	67		45	56
0,3	48	75		53	67	85
0,35	53	85		63	80	100
0,4	60	95		71	90	112
0,45	63	100		80	100	125
0,5	67	106		90	112	140	180
0,6	80	125		100	125	160	200
0,7	90	140		112	140	180	224
0,75	90	140		118	150	190	236
0,8	95	150	236	125	160	200	250	315
1,0	112	180	280	150	190	236	300	375
1,25	132	212	335	170	212	265	335	425
1,5	150	236	375	190	236	300	375	475
1,75	170	265	425	212	236	335	425	530
2,0	180	280	450	236	300	375	475	600
2,5	212	335	530	280	355	450	560	710
3,0	236	375	600	315	400	500	630	800
3,5	265	425	670	355	450	560	710	900
4,0	300	475	750	375	475	600	750	950
4,5	315	500	800	425	530	670	850	1060
5,0	335	530	850	450	560	710	900	1120
5,5	355	560	900	475	600	750	950	1180
6,0	375	600	950	500	630	800	1000	1250
8,0	450	710	1180	630	800	1000	1250	1600
mm	μ m	μ m	μ m	μ m	μ m	μ m	μ m;	μ m
Pitch	T:4	T:6	T:8	T:4	T:5	T:6	T:7	T:8
	Major Dia -Male threads			Minor Diameter - Female Threads

Row 2 (mm): header cell prints "μ m;" (stray semicolon) in the T:7 column — as printed

Worked example — external threads (M30, M12, M150, M200)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Name	Equation	Identity	Values
Designation			M30 x 3,5 - 6g	M12 x 1,25 -4h	M150 x 4 - 6e	M200 x 6 - 4g
Diameter	d	d	30	12	150	200
Pitch	P	P	3,5	1,25	4	6
Basic Pitch Dia	d 2 = d - 0,64952P	d 2	27,727	11,188	147,402	196,103
Basic Minor Dia	d1=d-1,08254,P	d 1	26,211	10,647	145,67	193,505
Fundamental Deviation	es	es	0,053	0	0,095	0,08
Tolerance Width diameter (d)	T d	T d	0,425	0,132	0,375	0,6
Tolerance Width Pitch dia,d 2	T d2	T d2	0,212	0,085	0,19	0,315
Extreme Deviation d	ei d = es+T d	ei d	0,478	0,132	0,47	0,68
Extreme Deviation d 2	ei d2 = es+T d2	ei d2	0,265	0,085	0,085	0,085
R min	R min = 0,125P	R min	0,438	0,156	0,5	0,75
z	See above		0,426	0,157	0,461	0,707
y	See above		0,064	0,021	0,09	0,125

Major Dia (max)	d max = d + es	d min	29,947	12	149,905	199,92
Major Dia (min)	d min = d + ei d	d max	29,522	11,868	149,53	199,32
Pitch Dia (max)	d 2min = d 2 +es	d 2min	27,674	11,188	147,307	196,023
Pitch Dia (min)	d 2max =d 2 +ei d2	d 2max	27,462	11,103	147,317	196,018
Minor Dia (min)	d 3min =d 1 -es-2z	d 3min	25,306	10,333	144,653	192,012
Minor Dia (max)	d 3max = d 1 -es-2y	d 3max	26,029	10,606	145,396	193,175

Row 12 (z): extreme deviation d2 row prints "0,265 | 0,085 | 0,085 | 0,085" (three identical 0,085 values where the M150/M200 cells differ on adjacent rows) — as printed, flagged not corrected
Row 14 (): Identity column prints "d min" on the Major Dia (max) row and "d max" on the Major Dia (min) row — the source's own labels swapped, carried verbatim

Worked example — internal threads (M30, M12, M150, M200)As printed on the collected page: legacy BS 3643 / BS ISO 965 tolerance data; decimal-comma notation carried verbatim except where the source itself prints a decimal point (flagged). µm columns are tolerance widths; mm columns are pitches/ranges. Verification: token-for-token equal to the x127 corpus (live-DOM capture 2026-11-01).
Name	Equation	Identity	Values
			M30 x 3,5 -6H	M12 x1,25 - 7H	M150 x 4 - 6G	M200 x 6 x 5H
Diameter	D	D	30	12	150	200
Pitch	P	P	3,5	1,25	4	6
Basic Pitch Dia	D 2 = D - 0,64952P	D 2	27,727	11,188	147,402	196,103
Basic Minor Diameter	D 1 =D-1,08254,P	D 1	26,211	10,647	145,67	193,505
Fundamental Deviation	EI	EI	0	0	0,06	0
Tolerance Width diameter (d)	T	T	0	0	0	0
Tolerance Width Pitch diameter (D2)	T D2	T D2	0,28	0,224	0,335	0,335
Tolerance Width Minor Dia(D1)	T D1	T D1	0,56	0,335	0,6	0,63
Extreme Deviation (D2)	ES D2 = EI+T D2	ES D2	0,28	0,224	0,395	0,335
Extreme Deviation (D1)	ES D1 = EI+T D1/	ES D1	0,56	0,335	0,66	0,63

Major Di (min)	D min	D min	30	12	150	200
Pitch Dia (min)	D 2min = D 2 +EI	D 2min	27,727	11,188	147,462	196,103
Pitch Dia (max)	D 2max =D 2 + ES D2	D 2max	28,007	11,412	147,797	196,438
Minor Dia (min)	D 1min = D 1 +EI	D 1min	26,211	10,647	145,73	193,505
Minor Dia (max)	D 1max =D 1 + ES D1	D 1max	26,771	10,982	146,33	194,135

Row 2 (Diameter): designation prints "M200 x 6 x 5H" (doubled pitch marker) — as printed
Row 7 (Tolerance Width diameter (d)): Tolerance Width diameter (d) row prints 0 / 0 / 0 / 0 — internal major diameter has no tabulated tolerance width in this source, carried verbatim

Materials

Tolerance class is a machining decision before it is a purchasing one: the plating allowance (6g clearance), the engagement length your joint offers (Short/Normal/Long shifts the class matrix) and the production route (rolled threads hold finer grades cheaper than cut) all live inside these tables. RFQ with thread size, pitch, class and engagement available — where the engagement is Short or Long we quote against the matrix shift explicitly rather than assuming a Medium-class default

Ordering & documentation

Documents

Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.

Quotation

The fastener family (Legacy BS 3643 / ISO 965 Thread Tolerance Data) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
Quantity per size and your target delivery date.
Destination country, and any required documents (for example a mill test certificate) so the quote includes them.

Sample & supply

Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.

Storage & shipping

Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.

Frequently asked questions

How do the engagement-length groups on this page change which tolerance class I should specify?

The engagement length — how many diameters of thread actually carry the load — moves the class because a long engagement accumulates pitch error, and a short one has little flank to spare. The tables encode it: for a given major-dia range and pitch, the Short/Normal/Long boundary table fixes which group your joint falls in, and the class matrices then hand out the grades — a Medium-class female thread at Normal engagement gets 6H (the everyday default), but the same thread at Long engagement shifts toward the looser end of the matrix to keep assembly possible over the accumulated error. The worked examples show the mechanism end to end: take the basic diameters, add the fundamental deviation for the position (g pulls the external thread down by the es value for its pitch), apply the tolerance width for the grade, and read off max/min. When your joint has an unusual engagement — short threads into a thin boss, or long engagement on a large casting — name it on the RFQ; quoting a default Medium/6H class against a Long-engagement joint is a classic assembly-floor fit problem, and it is visible in these tables before it is one in the stockroom.

Related knowledge

Request a Quote

Get factory-direct pricing from the manufacturer.

What to include in your inquiry

✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
✓ Sizes, lengths and thread type (metric or inch).
✓ Quantity per size and your target delivery date.
✓ Destination country, plus any coating or finish requirement.
✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.

✓ Factory-direct pricing
✓ Standard and custom specifications
✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
✓ Full fastener family support

Legacy BS 3643 / ISO 965 Thread Tolerance Data

Specifications

Materials

Ordering & documentation

Documents

Quotation

Sample & supply

Storage & shipping

Frequently asked questions

How do the engagement-length groups on this page change which tolerance class I should specify?

Related grades & products

Related knowledge

Request a Quote

What to include in your inquiry