Screw Thread Tolerances & Profiles

This page provides a comprehensive guide to ISO metric screw thread profiles and tolerance selection based on international standards. It explains the basic thread form, key dimensions, pitch selection, and tolerance classes used for internal (nuts) and external (bolts) threads. Engineers and designers can use this resource to understand how thread tolerances are defined, how to select appropriate tolerance classes (such as 6H/6g), and how to calculate thread limits using standard formulas and tables. The information is aligned with ISO 965, ISO 261, and BS 3643 standards, making it suitable for general engineering design and manufacturing applications.

Introduction..... Relevant Standards..... Example.....
Basic Thread Profile..... Profile Dimensions..... Basic Screw Dimensions.....
Screw Pitch..... Tolerance Class Description..... Tolerance Selection.....
Table relating Tol'ce grade to class and length..... Length Parameter.....
Table of Fundamental deviation (EI/es) against pitch.....
Table of Tolerance widths (Pitch Dia's).....
Table of Tolerance widths (Major Dia(Male) and Minor dia (Female).....
Root Contours..... Example in table form.....

Introduction

The notes below are outline in nature and are very much second best to the standards identified. Quality information is best found in the standards.

The notes on this page identify the basic ISO thread form and illustrate how the tolerances related to the thread form are developed from the simple rules provided in the relevant Standards.  Using the equations and tables available on this page it is possible to obtain the limits for all available dia-pitch-tolerance class combination.

The standard BS 3643 Part 1 relates to single start parallel screw threads of sizes from 1 to 300 mm.   Part 2 provides selected limits of sizes for the rang of screw threads.

The ISO standards quoted below are very similar the the British standards and provide essentially the same information.   The Standard ISO 965 Part 2 (size range 1-64mm)provides much more limited information compared to BS 3643 Part 2. ( size range 1-300mm ).

A table of ISO form screw threads from 1,6 to 300mm is found on ISO screw threads. This table relates to a medium tolerance grade screw nut combination (6H/6g) which is the grade implied if it is not specified.

Relevant Standards

BS 3643 Part 1:2007..ISO metric screw threads. Principles and basic data

BS 3643 Part 2:2007..ISO metric screw threads. Specification for selected limits of size

BS 3692:2001..ISO metric precision hexagon bolts, screws and nuts. Specification

BS ISO 965-1:1998 ...ISO general purpose metric screw threads. Tolerances (g.p.s.t.T). Principles and basic data

BS ISO 965-2:1998 ...ISO g.p.s.t.T . Limits of sizes for general purpose external and internal screw threads. Medium quality

BS ISO 261:1998 ...ISO general purpose metric screw threads. General plan

Tolerance selection Example

1) Tolerances for a M20 coarse thread medium fit.

The pitch for a M20 coarse thread is 2,5mm....Pitch
For the normal commercial applications a 6H/6g... Tolerance Selection

External Thread

Calculating the limits for the external thread diameter (d)
Fundamental deviation for es (g) = -42 μm.... Fundamental Deviation
The diameter tolerance width for an M20 g6 is 335μm. ....Tolerance Widths
The limits for d is therefore (max = 20 - 0,042 = 19,958 ),(min = 19.958 -0,335 = 19,623 )
Ans(max 19,958, min19,623 )

Calculating the limits for the external thread pitch diameter (d ₂)
The basic pitch diameter is 20 - 2*0,32476.P = 18,3762
Fundamental deviation es = -42 μm. ...Fundamental Deviation
The pitch tolerance width (T_d2) for an M20 g6 is 170μm..... Tolerance Widths
The limits for d ² is therefore (max = 18,3762 - 0,042 = 18,334 ),(min = 18.334 -0,170 = 18,164 )
Ans(max 18,334, min 18,164 )

Calculating the limits for the external thread root diameter (d ₃)... Root Contours
The basic root diameter d₁ is 20 - 2*0,54127.P = 17,294
To obtain the minimum root dia d_3min first calculate
z = H/4 + T_d2 /2 - P/8 = 0.21651P + 0,170/2 -0,125P = 0,3138
d _3min = d₁ - es -2z = 17,294 - 0.042 - 2*0,0,3138 = 16.624

The tables in the standards do not include a table value for d _3max
The table on this website ( Screw Threads ) uses a value d _3max = d₁ - es. = 17,252... This is the diameter of the Go-Gauge Profile.
A value more in line with the recommendations in the standards can be found using the equations found on this page Root Contours

(I will update the table in line with these recommendations over time - (R.B. 6/3/2008)

Internal Thread

Calculating the limits for the internal thread Minor diameter (d₁)
The basic minor diameter d₁ = 20 - 2*0,54127.P = 17,294
Fundamental deviation for EI(H) = 0 μm.... Fundamental Deviation
The diameter tolerance width for an M20 H6 is 450μm. ....Tolerance Widths
The limits for d is therefore (min = 17,294 + 0 = 17,294 ),(max = 17,294 + 0,450 = 17,744 )
Ans(max 17,744, min 17,294 )

Calculating the limits for the internal thread pitch diameter (d ₂)
The basic pitch diameter is 20 - 2*0,32476.P = 18,3762
Fundamental deviation EI = 0 μm. ...Fundamental Deviation
The pitch tolerance width (T_d2) for an M20 H6 is 224μm..... Tolerance Widths
The limits for d ² is therefore (min = 18,376 + 0 = 18.376 ),(max = 18.376 + 0,224 = 18,600 )
Ans(max 18,334, min 18,164 )

Calculating the limits for the internal thread major diameter D
The basic Major diameter D is 20
The minimum major dia D_min = 20,000

The Standards do not include a table value for D _max
It also does not seem to give guidance on how to obtain. They simply state that the thread should not transgress the basic profile.< /p>

Basic Thread Profile to BS 3643

Table of Basic Profile Dimensions

	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 Screw Dimensions

From these basic proportions it is very easy to obtain the basic thread dimensions a typical set of ISO metric coarse threads are identified with the basic dimensions as shown below

Table showing dimensions of some typical ISO metric coarse threads

Thread	Pitch	Major	Pitch Dia	Minor	Thread	Pitch	Major	Pitch Dia	Minor
	P	D/d	D₂ /d ₂	D₁ /d ₁		P	D/d	D₂ /d ₂	D₁ /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

Screw Pitch

There are a number of pitch values for each screw diameter. The selection as to the pitch is based on the application. The largest pitch option for diameters M1 to M64 is identified as the coarse pitch and is to one used for general engineering applications. A table of the coarse pitch series is provided below. Other pitch values for each diameter are called the fine series or constant series.

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

Fine series threads are only listed in the standards up to M33. The name fine does not imply higher quality. The fine series are listed below.

M1 / M1,1/ M1,2 / M1,4 / M1,6 / M1,8 (x 0,2)	M2 / M2,2 (x 0,25)	M2,5 / M3 / M3,5 (x 0,35)
M4 / M4,5 / M5,5 (x 0,5)	M6 / M7( x 0,75)	M8 x 1
M10 / 12 (x 1,25)	M14 / M16 / M18 / M20 / M22 (x 1,5)	M24 / M25 / M27/ M30 / M33 (x 2)

The constant thread series are identified in the standards for the screw range M8 upwards and are normally those pitches not classed as coarse or fine

Tolerances for External (screws) and Internal (Nuts) Threads

The method of applying manufacturing tolerances to the female and male threads such that they fit together is by use of the tolerance class which is a combination of the tolerance grade ( a number) and a tolerance position ( a letter). For the female threads the letter is upper class and for the male threads the letter is lower class. Therefore H6 is a tolerance grade for a female ( Internal ) thread and g6 is a tolerance grade for a male (External ) thread.

The tolerance band positions relative to the basic zero size are illustrated in the figure below

The (fundamental)tolerance position is defined as the nearest end of the tolerance band to the zero tolerance position (Dead size position). These positions are identified as EI for the female thread and es for the male thread.

There are a limited number of tolerance grades used to specify threads and the standards identify these grades for the Minor ( D₁ ) and Pitch ( D₂ )diameters of the female threads and the Major ( d ) and Pitch ( d₂ ) diameters of the male threads. Tolerance grades are not provided for none critical female major dia (D) and the male minor diameter (d₃). The numbers of grades used are listed below.

D₁ : tolerance grades 4,5,6,7 & 8
d : tolerance grades 4,6, & 8
D₂ tolerance grades 4,5,6,7 & 8
d₂ tolerance grades 3,4,5,6,8 & 9

The tolerance positions available are EI = G & H for female threads and es = e,f g, or h for male threads.

Selection of tolerance classes

To simplify the selection of the tolerance classes threads have been divide into three categories.

Fine ... For precision threads
Medium ...For general industrial use
Coarse .. For rough manufacture threads

The length of thread engagement is also used as a parameter for selection of the tolerance class

The following tables identifies the range of tolerance classes and the length of screws for selecting the length parameter.

Table showing tolerance classes

Female Threads
Class v	Tolerance Position G			Tolerance Position H
Class v	Short	Normal	Long	Short	Normal	long
Fine	-	-	-	4H	5H	6H
Medium	5G	6G	7G	5H	6H	7H
Rough	-	7G	8G	-	7H	8H

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

5h4h

Medium

7e6e

5g6g

7g6g

5h6h

7h6h

Rough

9g8g

....First Choice
....Second Choice
... Commercial Nuts /Bolt Threads
... Third choice to be avoided

Note:
When two shaft tolerance grades are shown the first is for the pitch dia and the second is for the major diameter.
When only one is shown it is the same for both diameters.

Table For Selecting Screw Length Parameter

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Basic Major Dia		Pitch	Length of Thread Engagement
Basic Major Dia			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

Table relating Fundamental deviation EI and es to Pitch

Pitch	Female Thread D₂,D₁		Male Thread d,d₂				Pitch	Female Thread D₂,D₁		Male Thread d,d₂
	EI		es					EI		es
	G	H	e	f	g	h		G	H	e	f	g	h
mm	μm	μm	μm	μm	μm	μm	mm	μm	μm	μm	μm	μm	μm
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

Table of T tolerance widths. (Pitch Diameters )
For Finished uncoated threads.

D2 /d2		Pitch	Pitch Diameter of internal threads					Pitch diameter of external threads
Over	To(&inc)	Pitch	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	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm
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	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm	μm
D2 /d2		Pitch	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

Table of T tolerance widths. (Major (Male) and Minor Diameters (Female)
For Finished uncoated threads.

Pitch	Major Dia -Male threads			Minor Diameter - Female Threads
Pitch	T:4	T:6	T:8	T:4	T:5	T:6	T:7	T:8
mm	μm	μm	μm	μm	μm	μm	μm;	μm
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	μm	μm	μm	μm	μm	μm	μm;	μm
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

Root Contours

For both internal and external threads the actual root contours shall not transgress the basic profile.

Note: In accordance with the requirements of BS EN ISO 898-1 for external fasteners of property class 8,8 and higher the root profile shall have non-reversing curvature, no part of the profile shall have a radius of less than 0,125P. It is advisable to attempt a truncation of C = H/6 as a basis for stress calculation of the minor dia d₃

In the maximum minor position d _3min the two radii of R_min = 0,125P will go through the corners of the no-go gauge profile and blend with the flanks of the maximum metal condition thread form.(see figure below)

The maximum truncation C_maxis calculated using the following equation

C_min = 0,125P

To calculate d_3min first obtain z

d_3min = d₁ - es -2z

To calculate d_3max first obtain y

d_3max = d₁ - es - 2y

Examples
Male Threads

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	d₂ =d-0,68952P	d₂	27,727	11,188	147,402	196,103
Basic Minor Dia	d1=d-1,08254,P	d₁	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,d₂	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 d₂	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_min = d + es	d_min	29,947	12	149,905	199,92
Major Dia (max)	d_max=d+ ei_d	d_max	29,522	11,868	149,53	199,32
Pitch Dia (max)	d_2min = d₂+es	d_2min	27,674	11,188	147,307	196,023
Pitch Dia (min)	d_2max=d₂+ei_d2	d_2max	27,462	11,103	147,317	196,018
Minor Dia (min)	d_3min =d₁-es-2z	d_3min	25,306	10,333	144,653	192,012
Minor Dia (max)	d_3max = d₁-es-2y	d_3max	26,029	10,606	145,396	193,175

Female Threads

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	D₂ = D-0,68952P	D₂	27,727	11,188	147,402	196,103
Basic Minor Diameter	D₁=D-1,08254,P	D₁	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 = D₂+EI	D_2min	27,727	11,188	147,462	196,103
Pitch Dia (max)	D_2max=D₂+ 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=D₁+ ES_D1	D_1max	26,771	10,982	146,33	194,135

ISO Screw Thread Profile and Tolerance Selection Guide

Introduction

Relevant Standards

Tolerance selection Example

External Thread

Internal Thread

Table of Basic Profile Dimensions

Basic Screw Dimensions

Screw Pitch

Tolerances for External (screws) and Internal (Nuts) Threads

Selection of tolerance classes

Table showing tolerance classes

See Also