Unified Threads (UNC/UNF/UNEF): Dimensions & Formulas

Table of Contents

List of Charts

* Easy access to all the data charts that appear on this page

Overview

The Unified Thread Standard (UTS) defines a 60° thread form in Inch dimensions as described in the ASME B1.1 standard. It is the North American equivalent of the ISO metric thread system. The UTS serves as the leading standard for bolts, nuts, and a wide variety of other threaded fasteners used in the USA and Canada. However, in recent years the metric thread standard is becoming more common.
The standard defines diameter and pitch combinations along with allowances, tolerances, and designations. It has the same 60° profile as the ISO metric screw thread, but the basic dimensions of each UTS thread were chosen as an inch fraction rather than a millimeter value.

Designation

Basic designation syntax:

Nominal Diameter in Inch Fraction
Pitch in TPI
Series: UNC / UNF / UNEF / UN
Class: 1A, 2A, 3A, 1B, 2B or 3B.

Diameter:

From 1/4″ and above the diameters are given in inch fractions. For example 1/4″, 3/4″, 1 1/4″.
Below 1/4″ the diameters are given by a series of numbers from #0 to #12. Each “number” describes an arbitrary diameter as shown in the below table.
It is also allowed to denote the diameters with a decimal value. For example 0.250 (1/4″), 0.4375 (7/16″), etc.

Standard Diameter numbers below 1/4″

Diameter Number	#0	#1	#2	#3	#4	#5	#6	#8	#10	#12
Diameter (Inch)	0.06	0.073	0.086	0.099	0.112	0.125	0.138	0.164	0.19	0.216
Diameter (mm)	1.524	1.8542	2.1844	2.5146	2.8448	3.175	3.5052	4.1656	4.8260	5.4864

Pitch:

By default, the pitch is given in TPI. For example, 1/4-20 means a thread with a pitch of 20 TPI (1/20=0.05″).
It is also allowed to denote the pitch by distance. For example, 1/4-0.05P means a thread with a pitch of 0.05″ (same as 20 TPI).

Series:

In most cases, the series will be UNC, UNF, or UNEF (Coarse, Fine, or Extra fine pitch).
ASTM B1.1, also defines several constant pitch series. These are denoted by ##-UN. For example, 12-UN or 8-UN. The pitch remains the same for the whole diameter range in these series. However, they are much less popular.

Class:

The class is defined by a two-character code.
- The first character is a digit between 1 and 3. 3=Tight fit, 2=Medium fit, and 1=Loose fit.
- The second character is a letter. A=External thread and B=Internal thread.
- For a detailed explanation of classes, read the dedicated section below.

Additional Parameters:

Direction: By default, the thread is right-hand. For a left-hand thread, add the suffix -LH.
Number of Starts: By default, all threads have a single start. Thus the lead equals the pitch. For a multiple-start thread, the lead is also indicated. For example: 3/4– 0.0625P – 0.1875L UNF denotes a 3/4″ UNF thread with 3 starts. (0.1875/0.0625=3)

Designation Examples of Unified Threads

Designation	Thread Series	Internal / External	Nominal Diameter	TPI	Pitch	Lead	Class	Number of Starts	Thread Direction
#8-32 UNC	UNC	undefined	0.164"	32	0.03125"	0.03125"	undefined	1	Right hand
1/4 -28 UNF-2A	UNF	External	0.25"	28	0.0357"	0.0357"	2A	1	Right hand
3/4-20 UNEF-3B	UNEF	Internal	0.75"	20	0.05"	0.05"	3B	1	Right hand
1-12 UN-1A	Constant Pitch 12 TPI	External	1"	12	0.0833"	0.0833"	1A	1	Right hand
3/4– 0.0625P – 0.1875L UNF-2A	UNF	External	0.75"	16	0.0625"	0.1875"	2A	3	Right hand
1/4 -28 UNF-2A-LH	UNF	External	0.25"	28	0.0357"	0.0357"	2A	1	Left hand

Possible Combinations (Diameter/Pitch)

The charts below show all the possible thread combinations that are defined in ASTM B1.1

UNC– Unified Inch Coarse Thread Series
UNF – Unified Inch Fine Thread Series
UNEF – Unified Inch Extra Fine Thread Series
##-UN – Unified Inch Constant PitchThread Series
Click to get the Full Thread Data-Sheet for a specific combination

Possible Combinations for 1/16″ – 1/4″

Possible Combinations for 5/16″ – 1 1/2″

Possible Combinations for 1 9/16″ – 6″

Basic Thread Dimensions (UNC, UNF & UNEF)

The basic dimensions are nominal dimensions of a unified thread profile without allowance and tolerances (The thread class defines that). They are based on standard ASTM B1.1. The basic dimensions can be used for design. However, for manufacturing and machining, you need the allowable range of each dimension. This data can be found in the standard or in the Limits and Dimensions section below. All the basic dimensions are derived from simple formulas based on the thread’s nominal diameter and pitch.

Symbols

List of symbols used in charts and formulas of Unified Inch Threads

Symbol	Explanation
Basic Parameters - Diameters and Pitch
D	Major (Basic) diameter of internal thread
D₁	Minor Diameter - Internal Thread
D₂	Pitch Diameter - Internal Thread
D₃	Major diameter, rounded root, internal thread
d	Major (Basic) diameter of external thread
d₁	Minor Diameter - External Thread
d₂	Pitch Diameter - External Thread
d₃	MMajor diameter, rounded root, internal thread
n	Number of threds per Inch (TPI)
P	Pitch (Distance)
L	Lead
Height Parameters
H	Height of fundamental triangle
h_s	Thread Height - External Thread
h_as	Thread addendum - External Thread
h_n	Thread Height - Internal Thread
h_an	Thread addendum - Internal Thread
Length Parameters
LE	Length of Engagment
L_ts	Length - External Thread
L_tn	Length- Internal Thread
Allowance, Deviation, and Tolerances
T_D1	Tolerance - D₁
T_D2	Tolerance - D₂
T_d	Tolerance - d
T_d2	Tolerance - d₂
es	Allowance - External Thread
Crest / Root Parameters
F_cs	Crest width - External Thread
F_rs	Root width - External Thread
F_cs	Crest width - Internal Thread
F_cs	Root width - Internal Thread

Formulas for basic dimensions

External Thread

\( \large d=\text{Basic Diameter} \)
\( \large P=\frac{1}{TPI} \)
\( \large H=\frac{\sqrt{3}}{2}\times{P} = 0.866025404\times{P} \)
\( \large h_s=\frac{5}{8}\times{H} \)
\( \large h_{as}=\frac{3}{8}\times{H}\)
\( \large d_2=d-{2}\times{h_{as}} \)
\( \large d_1=d-{2}\times{h_s}\)
\( \large F_{cs}=\frac{P}{8}\)
\( \large F_{rs}=\frac{P}{4}\)

internal thread

\( \large D=\text{Basic Diameter} \)
\( \large P=\frac{1}{TPI} \)
\( \large H=\frac{\sqrt{3}}{2}\times{P} = 0.866025404\times{P} \)
\( \large h_n=\frac{5}{8}\times{H} \)
\( \large h_{an}=\frac{1}{4}\times{H}\)
\( \large D_1=D-{2}\times{h_n}\)
\( \large D_2=D1+{2}\times{h_{an}}\)
\( \large F_{rn}=\frac{P}{8}\)
\( \large F_{cn}=\frac{P}{4}\)

Unified Inch Threads Dimensions Charts

UNC Series Basic Dimensions chart

Click the Thread Link to get the Full Thread Data for all classes
All dimensions are in inches. To view the Metric translation, click the Thread Link
Click icon to show Additional columns

Click icon to show Full Thread Data

Thread	Basic Diam	TPI	Pitch	Pitch Diam	Thread Height	Cres/ Root	Tap Drill Size	Lead Angle	Minor Diameter	Thread addendum	series	id
#1 - 64 UNC	0.073	64	0.0156	0.0629	0.0085	0.0039	0.0588	4.52°	0.0544	0.0051	UNC	2
#2 - 56 UNC	0.086	56	0.0179	0.0744	0.0097	0.0045	0.0698	4.37°	0.0647	0.0058	UNC	4
#3 - 48 UNC	0.099	48	0.0208	0.0855	0.0113	0.0052	0.08	4.44°	0.0742	0.0068	UNC	6
#4 - 40 UNC	0.112	40	0.0250	0.0958	0.0135	0.0063	0.0893	4.75°	0.0822	0.0081	UNC	8
#5 - 40 UNC	0.125	40	0.0250	0.1088	0.0135	0.0063	0.1023	4.18°	0.0952	0.0081	UNC	10
#6 - 32 UNC	0.138	32	0.0313	0.1177	0.0169	0.0078	0.1096	4.83°	0.1008	0.0101	UNC	12
#8 - 32 UNC	0.164	32	0.0313	0.1437	0.0169	0.0078	0.1356	3.96°	0.1268	0.0101	UNC	15
#10 - 24 UNC	0.19	24	0.0417	0.1629	0.0226	0.0104	0.1521	4.65°	0.1404	0.0135	UNC	18
#12 - 24 UNC	0.216	24	0.0417	0.1889	0.0226	0.0104	0.1781	4.02°	0.1664	0.0135	UNC	21
1/4 - 20 UNC	0.25	20	0.0500	0.2175	0.0271	0.0125	0.2045	4.18°	0.1905	0.0162	UNC	26
5/16 - 18 UNC	0.312	18	0.0556	0.2759	0.0301	0.0139	0.2614	3.67°	0.2458	0.018	UNC	32
3/8 - 16 UNC	0.375	16	0.0625	0.3344	0.0338	0.0156	0.3181	3.4°	0.3006	0.0203	UNC	38
7/16 - 14 UNC	0.437	14	0.0714	0.3906	0.0387	0.0179	0.372	3.33°	0.3519	0.0232	UNC	45
1/2 - 13 UNC	0.5	13	0.0769	0.45	0.0416	0.0192	0.43	3.11°	0.4084	0.025	UNC	52
9/16 - 12 UNC	0.562	12	0.0833	0.5079	0.0451	0.0208	0.4862	2.99°	0.4628	0.0271	UNC	59
5/8 - 11 UNC	0.625	11	0.0909	0.566	0.0492	0.0227	0.5423	2.93°	0.5167	0.0295	UNC	67
3/4 - 10 UNC	0.75	10	0.1000	0.685	0.0541	0.025	0.659	2.66°	0.6309	0.0325	UNC	81
7/8 - 9 UNC	0.875	9	0.1111	0.8028	0.0601	0.0278	0.7739	2.52°	0.7427	0.0361	UNC	95
1 - 8 UNC	1	8	0.1250	0.9188	0.0677	0.0313	0.8863	2.48°	0.8512	0.0406	UNC	109
1 1/8 - 7 UNC	1.125	7	0.1429	1.0322	0.0773	0.0357	0.995	2.52°	0.9549	0.0464	UNC	124
1 1/4 - 7 UNC	1.25	7	0.1429	1.1572	0.0773	0.0357	1.12	2.25°	1.0799	0.0464	UNC	138
1 3/8 - 6 UNC	1.375	6	0.1667	1.2667	0.0902	0.0417	1.2233	2.4°	1.1765	0.0541	UNC	152
1 1/2 - 6 UNC	1.5	6	0.1667	1.3917	0.0902	0.0417	1.3483	2.18°	1.3015	0.0541	UNC	168
1 3/4 - 5 UNC	1.75	5	0.2000	1.6201	0.1083	0.05	1.568	2.25°	1.5118	0.065	UNC	195
2 - 4.5 UNC	2	4	0.2222	1.8557	0.1203	0.0556	1.7978	2.18°	1.7354	0.0722	UNC	216
2 1/4 - 4.5 UNC	2.25	4	0.2222	2.1057	0.1203	0.0556	2.0478	1.92°	1.9854	0.0722	UNC	227
2 1/2 - 4 UNC	2.5	4	0.2500	2.3376	0.1353	0.0625	2.2725	1.95°	2.2023	0.0812	UNC	238
2 3/4 - 4 UNC	2.75	4	0.2500	2.5876	0.1353	0.0625	2.5225	1.76°	2.4523	0.0812	UNC	251
3 - 4 UNC	3	4	0.2500	2.8376	0.1353	0.0625	2.7725	1.61°	2.7023	0.0812	UNC	264
3 1/4 - 4 UNC	3.25	4	0.2500	3.0876	0.1353	0.0625	3.0225	1.48°	2.9523	0.0812	UNC	276
3 1/2 - 4 UNC	3.5	4	0.2500	3.3376	0.1353	0.0625	3.2725	1.37°	3.2023	0.0812	UNC	287
3 3/4 - 4 UNC	3.75	4	0.2500	3.5876	0.1353	0.0625	3.5225	1.27°	3.4523	0.0812	UNC	298
4 - 4 UNC	4	4	0.2500	3.8376	0.1353	0.0625	3.7725	1.19°	3.7023	0.0812	UNC	309

UNF Series Basic Dimensions chart

Click icon to show Full Thread Data

Thread	Basic Diam	TPI	Pitch	Pitch Diam	Thread Height	Cres/ Root	Tap Drill Size	Lead Angle	Minor Diameter	Thread addendum	series	id
#0 - 80 UNF	0.06	80	0.0125	0.0519	0.0068	0.0031	0.0486	4.39°	0.0451	0.0041	UNF	1
#1 - 72 UNF	0.073	72	0.0139	0.064	0.0075	0.0035	0.0604	3.95°	0.0565	0.0045	UNF	3
#2 - 64 UNF	0.086	64	0.0156	0.0759	0.0085	0.0039	0.0718	3.75°	0.0674	0.0051	UNF	5
#3 - 56 UNF	0.099	56	0.0179	0.0874	0.0097	0.0045	0.0828	3.72°	0.0777	0.0058	UNF	7
#4 - 48 UNF	0.112	48	0.0208	0.0985	0.0113	0.0052	0.093	3.85°	0.0872	0.0068	UNF	9
#5 - 44 UNF	0.125	44	0.0227	0.1102	0.0123	0.0057	0.1043	3.75°	0.0979	0.0074	UNF	11
#6 - 40 UNF	0.138	40	0.0250	0.1218	0.0135	0.0063	0.1153	3.74°	0.1082	0.0081	UNF	13
#8 - 36 UNF	0.164	36	0.0278	0.146	0.015	0.0069	0.1387	3.47°	0.1309	0.009	UNF	16
#10 - 32 UNF	0.19	32	0.0313	0.1697	0.0169	0.0078	0.1616	3.35°	0.1528	0.0101	UNF	19
#12 - 28 UNF	0.216	28	0.0357	0.1928	0.0193	0.0089	0.1835	3.37°	0.1735	0.0116	UNF	22
1/4 - 28 UNF	0.25	28	0.0357	0.2268	0.0193	0.0089	0.2175	2.87°	0.2075	0.0116	UNF	27
5/16 - 24 UNF	0.312	24	0.0417	0.2849	0.0226	0.0104	0.2741	2.67°	0.2624	0.0135	UNF	33
3/8 - 24 UNF	0.375	24	0.0417	0.3479	0.0226	0.0104	0.3371	2.18°	0.3254	0.0135	UNF	39
7/16 - 20 UNF	0.437	20	0.0500	0.4045	0.0271	0.0125	0.3915	2.25°	0.3775	0.0162	UNF	46
1/2 - 20 UNF	0.5	20	0.0500	0.4675	0.0271	0.0125	0.4545	1.95°	0.4405	0.0162	UNF	53
9/16 - 18 UNF	0.562	18	0.0556	0.5259	0.0301	0.0139	0.5114	1.93°	0.4958	0.018	UNF	60
5/8 - 18 UNF	0.625	18	0.0556	0.5889	0.0301	0.0139	0.5744	1.72°	0.5588	0.018	UNF	68
3/4 - 16 UNF	0.75	16	0.0625	0.7094	0.0338	0.0156	0.6931	1.61°	0.6756	0.0203	UNF	82
7/8 - 14 UNF	0.875	14	0.0714	0.8286	0.0387	0.0179	0.81	1.57°	0.7899	0.0232	UNF	96
1 - 12 UNF	1	12	0.0833	0.9459	0.0451	0.0208	0.9242	1.61°	0.9008	0.0271	UNF	110
1 1/8 - 12 UNF	1.125	12	0.0833	1.0709	0.0451	0.0208	1.0492	1.42°	1.0258	0.0271	UNF	125
1 1/4 - 12 UNF	1.25	12	0.0833	1.1959	0.0451	0.0208	1.1742	1.27°	1.1508	0.0271	UNF	139
1 3/8 - 12 UNF	1.375	12	0.0833	1.3209	0.0451	0.0208	1.2992	1.15°	1.2758	0.0271	UNF	153
1 1/2 - 12 UNF	1.5	12	0.0833	1.4459	0.0451	0.0208	1.4242	1.05°	1.4008	0.0271	UNF	169

UNEF Series Basic Dimensions chart

Click icon to show Full Thread Data

Thread	Basic Diam	TPI	Pitch	Pitch Diam	Thread Height	Cres/ Root	Tap Drill Size	Lead Angle	Minor Diameter	Thread addendum	series	id
#12 - 32 UNEF	0.216	32	0.0313	0.1957	0.0169	0.0078	0.1876	2.91°	0.1788	0.0101	UNEF	23
1/4 - 32 UNEF	0.25	32	0.0313	0.2297	0.0169	0.0078	0.2216	2.48°	0.2128	0.0101	UNEF	28
5/16 - 32 UNEF	0.312	32	0.0313	0.2917	0.0169	0.0078	0.2836	1.95°	0.2748	0.0101	UNEF	34
3/8 - 32 UNEF	0.375	32	0.0313	0.3547	0.0169	0.0078	0.3466	1.61°	0.3378	0.0101	UNEF	40
7/16 - 28 UNEF	0.437	28	0.0357	0.4138	0.0193	0.0089	0.4045	1.57°	0.3945	0.0116	UNEF	47
1/2 - 28 UNEF	0.5	28	0.0357	0.4768	0.0193	0.0089	0.4675	1.37°	0.4575	0.0116	UNEF	54
9/16 - 24 UNEF	0.562	24	0.0417	0.5349	0.0226	0.0104	0.5241	1.42°	0.5124	0.0135	UNEF	61
5/8 - 24 UNEF	0.625	24	0.0417	0.5979	0.0226	0.0104	0.5871	1.27°	0.5754	0.0135	UNEF	69
11/16 - 24 UNEF	0.687	24	0.0417	0.6599	0.0226	0.0104	0.6491	1.15°	0.6374	0.0135	UNEF	75
3/4 - 20 UNEF	0.75	20	0.0500	0.7175	0.0271	0.0125	0.7045	1.27°	0.6905	0.0162	UNEF	83
13/16 - 20 UNEF	0.812	20	0.0500	0.7795	0.0271	0.0125	0.7665	1.17°	0.7525	0.0162	UNEF	89
7/8 - 20 UNEF	0.875	20	0.0500	0.8425	0.0271	0.0125	0.8295	1.08°	0.8155	0.0162	UNEF	97
15/16 - 20 UNEF	0.937	20	0.0500	0.9045	0.0271	0.0125	0.8915	1.01°	0.8775	0.0162	UNEF	103
1 - 20 UNEF	1	20	0.0500	0.9675	0.0271	0.0125	0.9545	0.94°	0.9405	0.0162	UNEF	111
1 1/16 - 18 UNEF	1.062	18	0.0556	1.0259	0.0301	0.0139	1.0114	0.99°	0.9958	0.018	UNEF	118
1 1/8 - 18 UNEF	1.125	18	0.0556	1.0889	0.0301	0.0139	1.0744	0.93°	1.0588	0.018	UNEF	126
1 3/16 - 18 UNEF	1.187	18	0.0556	1.1509	0.0301	0.0139	1.1364	0.88°	1.1208	0.018	UNEF	132
1 1/4 - 18 UNEF	1.25	18	0.0556	1.2139	0.0301	0.0139	1.1994	0.83°	1.1838	0.018	UNEF	140
1 5/16 - 18 UNEF	1.312	18	0.0556	1.2759	0.0301	0.0139	1.2614	0.79°	1.2458	0.018	UNEF	146
1 3/8 - 18 UNEF	1.375	18	0.0556	1.3389	0.0301	0.0139	1.3244	0.76°	1.3088	0.018	UNEF	154
1 7/16 - 18 UNEF	1.437	18	0.0556	1.4009	0.0301	0.0139	1.3864	0.72°	1.3708	0.018	UNEF	161
1 1/2 - 18 UNEF	1.5	18	0.0556	1.4639	0.0301	0.0139	1.4494	0.69°	1.4338	0.018	UNEF	170
1 9/16 - 18 UNEF	1.562	18	0.0556	1.5259	0.0301	0.0139	1.5114	0.66°	1.4958	0.018	UNEF	177
1 5/8 - 18 UNEF	1.625	18	0.0556	1.5889	0.0301	0.0139	1.5744	0.64°	1.5588	0.018	UNEF	183
1 11/16 - 18 UNEF	1.687	18	0.0556	1.6509	0.0301	0.0139	1.6364	0.61°	1.6208	0.018	UNEF	189

UN Constant Pitch Series Basic Dimensions chart

Click icon to show Full Thread Data

Thread	Basic Diam	TPI	Pitch	Pitch Diam	Thread Height	Cres/ Root	Tap Drill Size	Lead Angle	Minor Diameter	Thread addendum	series	id
9/16 - 12 12-UN	0.562	12	0.0833	0.5079	0.0451	0.0208	0.4862	2.99°	0.4628	0.0271	12-UN	62
5/8 - 12 12-UN	0.625	12	0.0833	0.5709	0.0451	0.0208	0.5492	2.66°	0.5258	0.0271	12-UN	70
11/16 - 12 12-UN	0.687	12	0.0833	0.6329	0.0451	0.0208	0.6112	2.4°	0.5878	0.0271	12-UN	76
3/4 - 12 12-UN	0.75	12	0.0833	0.6959	0.0451	0.0208	0.6742	2.18°	0.6508	0.0271	12-UN	84
13/16 - 12 12-UN	0.812	12	0.0833	0.7579	0.0451	0.0208	0.7362	2°	0.7128	0.0271	12-UN	90
7/8 - 12 12-UN	0.875	12	0.0833	0.8209	0.0451	0.0208	0.7992	1.85°	0.7758	0.0271	12-UN	98
15/16 - 12 12-UN	0.937	12	0.0833	0.8829	0.0451	0.0208	0.8612	1.72°	0.8378	0.0271	12-UN	104
1 - 12 12-UN	1	12	0.0833	0.9459	0.0451	0.0208	0.9242	1.61°	0.9008	0.0271	12-UN	113
1 1/16 - 12 12-UN	1.062	12	0.0833	1.0079	0.0451	0.0208	0.9862	1.51°	0.9628	0.0271	12-UN	120
1 1/8 - 12 12-UN	1.125	12	0.0833	1.0709	0.0451	0.0208	1.0492	1.42°	1.0258	0.0271	12-UN	128
1 3/16 - 12 12-UN	1.187	12	0.0833	1.1329	0.0451	0.0208	1.1112	1.34°	1.0878	0.0271	12-UN	134
1 1/4 - 12 12-UN	1.25	12	0.0833	1.1959	0.0451	0.0208	1.1742	1.27°	1.1508	0.0271	12-UN	142
1 5/16 - 12 12-UN	1.312	12	0.0833	1.2579	0.0451	0.0208	1.2362	1.21°	1.2128	0.0271	12-UN	148
1 3/8 - 12 12-UN	1.375	12	0.0833	1.3209	0.0451	0.0208	1.2992	1.15°	1.2758	0.0271	12-UN	157
1 7/16 - 12 12-UN	1.437	12	0.0833	1.3829	0.0451	0.0208	1.3612	1.1°	1.3378	0.0271	12-UN	164
1 1/2 - 12 12-UN	1.5	12	0.0833	1.4459	0.0451	0.0208	1.4242	1.05°	1.4008	0.0271	12-UN	173
1 9/16 - 12 12-UN	1.562	12	0.0833	1.5079	0.0451	0.0208	1.4862	1.01°	1.4628	0.0271	12-UN	180
1 5/8 - 12 12-UN	1.625	12	0.0833	1.5709	0.0451	0.0208	1.5492	0.97°	1.5258	0.0271	12-UN	186
1 11/16 - 12 12-UN	1.687	12	0.0833	1.6329	0.0451	0.0208	1.6112	0.93°	1.5878	0.0271	12-UN	192
1 3/4 - 12 12-UN	1.75	12	0.0833	1.6959	0.0451	0.0208	1.6742	0.9°	1.6508	0.0271	12-UN	198
1 13/16 - 12 12-UN	1.812	12	0.0833	1.7579	0.0451	0.0208	1.7362	0.86°	1.7128	0.0271	12-UN	203
1 7/8 - 12 12-UN	1.875	12	0.0833	1.8209	0.0451	0.0208	1.7992	0.83°	1.7758	0.0271	12-UN	208
1 15/16 - 12 12-UN	1.937	12	0.0833	1.8829	0.0451	0.0208	1.8612	0.81°	1.8378	0.0271	12-UN	213
2 - 12 12-UN	2	12	0.0833	1.9459	0.0451	0.0208	1.9242	0.78°	1.9008	0.0271	12-UN	219
2 1/8 - 12 12-UN	2.125	12	0.0833	2.0709	0.0451	0.0208	2.0492	0.73°	2.0258	0.0271	12-UN	224
2 1/4 - 12 12-UN	2.25	12	0.0833	2.1959	0.0451	0.0208	2.1742	0.69°	2.1508	0.0271	12-UN	230
2 3/8 - 12 12-UN	2.375	12	0.0833	2.3209	0.0451	0.0208	2.2992	0.65°	2.2758	0.0271	12-UN	235
2 1/2 - 12 12-UN	2.5	12	0.0833	2.4459	0.0451	0.0208	2.4242	0.62°	2.4008	0.0271	12-UN	242
2 5/8 - 12 12-UN	2.625	12	0.0833	2.5709	0.0451	0.0208	2.5492	0.59°	2.5258	0.0271	12-UN	248
2 3/4 - 12 12-UN	2.75	12	0.0833	2.6959	0.0451	0.0208	2.6742	0.56°	2.6508	0.0271	12-UN	255
2 7/8 - 12 12-UN	2.875	12	0.0833	2.8209	0.0451	0.0208	2.7992	0.54°	2.7758	0.0271	12-UN	261
3 - 12 12-UN	3	12	0.0833	2.9459	0.0451	0.0208	2.9242	0.52°	2.9008	0.0271	12-UN	268
3 1/8 - 12 12-UN	3.125	12	0.0833	3.0709	0.0451	0.0208	3.0492	0.49°	3.0258	0.0271	12-UN	274
3 1/4 - 12 12-UN	3.25	12	0.0833	3.1959	0.0451	0.0208	3.1742	0.48°	3.1508	0.0271	12-UN	280
3 3/8 - 12 12-UN	3.375	12	0.0833	3.3209	0.0451	0.0208	3.2992	0.46°	3.2758	0.0271	12-UN	285
3 1/2 - 12 12-UN	3.5	12	0.0833	3.4459	0.0451	0.0208	3.4242	0.44°	3.4008	0.0271	12-UN	291
3 5/8 - 12 12-UN	3.625	12	0.0833	3.5709	0.0451	0.0208	3.5492	0.43°	3.5258	0.0271	12-UN	296
3 3/4 - 12 12-UN	3.75	12	0.0833	3.6959	0.0451	0.0208	3.6742	0.41°	3.6508	0.0271	12-UN	302
3 7/8 - 12 12-UN	3.875	12	0.0833	3.8209	0.0451	0.0208	3.7992	0.4°	3.7758	0.0271	12-UN	307
4 - 12 12-UN	4	12	0.0833	3.9459	0.0451	0.0208	3.9242	0.39°	3.9008	0.0271	12-UN	313
4 1/8 - 12 12-UN	4.125	12	0.0833	4.0709	0.0451	0.0208	4.0492	0.37°	4.0258	0.0271	12-UN	318
4 1/4 - 12 12-UN	4.25	12	0.0833	4.1959	0.0451	0.0208	4.1742	0.36°	4.1508	0.0271	12-UN	323
4 3/8 - 12 12-UN	4.375	12	0.0833	4.3209	0.0451	0.0208	4.2992	0.35°	4.2758	0.0271	12-UN	328
4 1/2 - 12 12-UN	4.5	12	0.0833	4.4459	0.0451	0.0208	4.4242	0.34°	4.4008	0.0271	12-UN	333
4 5/8 - 12 12-UN	4.625	12	0.0833	4.5709	0.0451	0.0208	4.5492	0.33°	4.5258	0.0271	12-UN	338
4 3/4 - 12 12-UN	4.75	12	0.0833	4.6959	0.0451	0.0208	4.6742	0.32°	4.6508	0.0271	12-UN	344
4 7/8 - 12 12-UN	4.875	12	0.0833	4.8209	0.0451	0.0208	4.7992	0.32°	4.7758	0.0271	12-UN	349
5 - 12 12-UN	5	12	0.0833	4.9459	0.0451	0.0208	4.9242	0.31°	4.9008	0.0271	12-UN	354
5 1/8 - 12 12-UN	5.125	12	0.0833	5.0709	0.0451	0.0208	5.0492	0.3°	5.0258	0.0271	12-UN	359
5 1/4 - 12 12-UN	5.25	12	0.0833	5.1959	0.0451	0.0208	5.1742	0.29°	5.1508	0.0271	12-UN	364
5 3/8 - 12 12-UN	5.375	12	0.0833	5.3209	0.0451	0.0208	5.2992	0.29°	5.2758	0.0271	12-UN	369
5 1/2 - 12 12-UN	5.5	12	0.0833	5.4459	0.0451	0.0208	5.4242	0.28°	5.4008	0.0271	12-UN	374
5 5/8 - 12 12-UN	5.625	12	0.0833	5.5709	0.0451	0.0208	5.5492	0.27°	5.5258	0.0271	12-UN	379
5 3/4 - 12 12-UN	5.75	12	0.0833	5.6959	0.0451	0.0208	5.6742	0.27°	5.6508	0.0271	12-UN	384
5 7/8 - 12 12-UN	5.875	12	0.0833	5.8209	0.0451	0.0208	5.7992	0.26°	5.7758	0.0271	12-UN	389
6 - 12 12-UN	6	12	0.0833	5.9459	0.0451	0.0208	5.9242	0.26°	5.9008	0.0271	12-UN	394
3/8 - 16 16-UN	0.375	16	0.0625	0.3344	0.0338	0.0156	0.3181	3.4°	0.3006	0.0203	16-UN	41
7/16 - 16 16-UN	0.437	16	0.0625	0.3964	0.0338	0.0156	0.3801	2.87°	0.3626	0.0203	16-UN	48
1/2 - 16 16-UN	0.5	16	0.0625	0.4594	0.0338	0.0156	0.4431	2.48°	0.4256	0.0203	16-UN	55
9/16 - 16 16-UN	0.562	16	0.0625	0.5214	0.0338	0.0156	0.5051	2.19°	0.4876	0.0203	16-UN	63
5/8 - 16 16-UN	0.625	16	0.0625	0.5844	0.0338	0.0156	0.5681	1.95°	0.5506	0.0203	16-UN	71
11/16 - 16 16-UN	0.687	16	0.0625	0.6464	0.0338	0.0156	0.6301	1.76°	0.6126	0.0203	16-UN	77
3/4 - 16 16-UN	0.75	16	0.0625	0.7094	0.0338	0.0156	0.6931	1.61°	0.6756	0.0203	16-UN	85
13/16 - 16 16-UN	0.812	16	0.0625	0.7714	0.0338	0.0156	0.7551	1.48°	0.7376	0.0203	16-UN	91
7/8 - 16 16-UN	0.875	16	0.0625	0.8344	0.0338	0.0156	0.8181	1.37°	0.8006	0.0203	16-UN	99
15/16 - 16 16-UN	0.937	16	0.0625	0.8964	0.0338	0.0156	0.8801	1.27°	0.8626	0.0203	16-UN	105
1 - 16 16-UN	1	16	0.0625	0.9594	0.0338	0.0156	0.9431	1.19°	0.9256	0.0203	16-UN	114
1 1/16 - 16 16-UN	1.062	16	0.0625	1.0214	0.0338	0.0156	1.0051	1.12°	0.9876	0.0203	16-UN	121
1 1/8 - 16 16-UN	1.125	16	0.0625	1.0844	0.0338	0.0156	1.0681	1.05°	1.0506	0.0203	16-UN	129
1 3/16 - 16 16-UN	1.187	16	0.0625	1.1464	0.0338	0.0156	1.1301	0.99°	1.1126	0.0203	16-UN	135
1 1/4 - 16 16-UN	1.25	16	0.0625	1.2094	0.0338	0.0156	1.1931	0.94°	1.1756	0.0203	16-UN	143
1 5/16 - 16 16-UN	1.312	16	0.0625	1.2714	0.0338	0.0156	1.2551	0.9°	1.2376	0.0203	16-UN	149
1 3/8 - 16 16-UN	1.375	16	0.0625	1.3344	0.0338	0.0156	1.3181	0.85°	1.3006	0.0203	16-UN	158
1 7/16 - 16 16-UN	1.437	16	0.0625	1.3964	0.0338	0.0156	1.3801	0.82°	1.3626	0.0203	16-UN	165
1 1/2 - 16 16-UN	1.5	16	0.0625	1.4594	0.0338	0.0156	1.4431	0.78°	1.4256	0.0203	16-UN	174
1 9/16 - 16 16-UN	1.562	16	0.0625	1.5214	0.0338	0.0156	1.5051	0.75°	1.4876	0.0203	16-UN	181
1 5/8 - 16 16-UN	1.625	16	0.0625	1.5844	0.0338	0.0156	1.5681	0.72°	1.5506	0.0203	16-UN	187
1 11/16 - 16 16-UN	1.687	16	0.0625	1.6464	0.0338	0.0156	1.6301	0.69°	1.6126	0.0203	16-UN	193
1 3/4 - 16 16-UN	1.75	16	0.0625	1.7094	0.0338	0.0156	1.6931	0.67°	1.6756	0.0203	16-UN	199
1 13/16 - 16 16-UN	1.812	16	0.0625	1.7714	0.0338	0.0156	1.7551	0.64°	1.7376	0.0203	16-UN	204
1 7/8 - 16 16-UN	1.875	16	0.0625	1.8344	0.0338	0.0156	1.8181	0.62°	1.8006	0.0203	16-UN	209
1 15/16 - 16 16-UN	1.937	16	0.0625	1.8964	0.0338	0.0156	1.8801	0.6°	1.8626	0.0203	16-UN	214
2 - 16 16-UN	2	16	0.0625	1.9594	0.0338	0.0156	1.9431	0.58°	1.9256	0.0203	16-UN	220
2 1/8 - 16 16-UN	2.125	16	0.0625	2.0844	0.0338	0.0156	2.0681	0.55°	2.0506	0.0203	16-UN	225
2 1/4 - 16 16-UN	2.25	16	0.0625	2.2094	0.0338	0.0156	2.1931	0.52°	2.1756	0.0203	16-UN	231
2 3/8 - 16 16-UN	2.375	16	0.0625	2.3344	0.0338	0.0156	2.3181	0.49°	2.3006	0.0203	16-UN	236
2 1/2 - 16 16-UN	2.5	16	0.0625	2.4594	0.0338	0.0156	2.4431	0.46°	2.4256	0.0203	16-UN	243
2 5/8 - 16 16-UN	2.625	16	0.0625	2.5844	0.0338	0.0156	2.5681	0.44°	2.5506	0.0203	16-UN	249
2 3/4 - 16 16-UN	2.75	16	0.0625	2.7094	0.0338	0.0156	2.6931	0.42°	2.6756	0.0203	16-UN	256
2 7/8 - 16 16-UN	2.875	16	0.0625	2.8344	0.0338	0.0156	2.8181	0.4°	2.8006	0.0203	16-UN	262
3 - 16 16-UN	3	16	0.0625	2.9594	0.0338	0.0156	2.9431	0.39°	2.9256	0.0203	16-UN	269
3 1/8 - 16 16-UN	3.125	16	0.0625	3.0844	0.0338	0.0156	3.0681	0.37°	3.0506	0.0203	16-UN	275
3 1/4 - 16 16-UN	3.25	16	0.0625	3.2094	0.0338	0.0156	3.1931	0.36°	3.1756	0.0203	16-UN	281
3 3/8 - 16 16-UN	3.375	16	0.0625	3.3344	0.0338	0.0156	3.3181	0.34°	3.3006	0.0203	16-UN	286
3 1/2 - 16 16-UN	3.5	16	0.0625	3.4594	0.0338	0.0156	3.4431	0.33°	3.4256	0.0203	16-UN	292
3 5/8 - 16 16-UN	3.625	16	0.0625	3.5844	0.0338	0.0156	3.5681	0.32°	3.5506	0.0203	16-UN	297
3 3/4 - 16 16-UN	3.75	16	0.0625	3.7094	0.0338	0.0156	3.6931	0.31°	3.6756	0.0203	16-UN	303
3 7/8 - 16 16-UN	3.875	16	0.0625	3.8344	0.0338	0.0156	3.8181	0.3°	3.8006	0.0203	16-UN	308
4 - 16 16-UN	4	16	0.0625	3.9594	0.0338	0.0156	3.9431	0.29°	3.9256	0.0203	16-UN	314
4 1/8 - 16 16-UN	4.125	16	0.0625	4.0844	0.0338	0.0156	4.0681	0.28°	4.0506	0.0203	16-UN	319
4 1/4 - 16 16-UN	4.25	16	0.0625	4.2094	0.0338	0.0156	4.1931	0.27°	4.1756	0.0203	16-UN	324
4 3/8 - 16 16-UN	4.375	16	0.0625	4.3344	0.0338	0.0156	4.3181	0.26°	4.3006	0.0203	16-UN	329
4 1/2 - 16 16-UN	4.5	16	0.0625	4.4594	0.0338	0.0156	4.4431	0.26°	4.4256	0.0203	16-UN	334
4 5/8 - 16 16-UN	4.625	16	0.0625	4.5844	0.0338	0.0156	4.5681	0.25°	4.5506	0.0203	16-UN	339
4 3/4 - 16 16-UN	4.75	16	0.0625	4.7094	0.0338	0.0156	4.6931	0.24°	4.6756	0.0203	16-UN	345
4 7/8 - 16 16-UN	4.875	16	0.0625	4.8344	0.0338	0.0156	4.8181	0.24°	4.8006	0.0203	16-UN	350
5 - 16 16-UN	5	16	0.0625	4.9594	0.0338	0.0156	4.9431	0.23°	4.9256	0.0203	16-UN	355
5 1/8 - 16 16-UN	5.125	16	0.0625	5.0844	0.0338	0.0156	5.0681	0.22°	5.0506	0.0203	16-UN	360
5 1/4 - 16 16-UN	5.25	16	0.0625	5.2094	0.0338	0.0156	5.1931	0.22°	5.1756	0.0203	16-UN	365
5 3/8 - 16 16-UN	5.375	16	0.0625	5.3344	0.0338	0.0156	5.3181	0.21°	5.3006	0.0203	16-UN	370
5 1/2 - 16 16-UN	5.5	16	0.0625	5.4594	0.0338	0.0156	5.4431	0.21°	5.4256	0.0203	16-UN	375
5 5/8 - 16 16-UN	5.625	16	0.0625	5.5844	0.0338	0.0156	5.5681	0.2°	5.5506	0.0203	16-UN	380
5 3/4 - 16 16-UN	5.75	16	0.0625	5.7094	0.0338	0.0156	5.6931	0.2°	5.6756	0.0203	16-UN	385
5 7/8 - 16 16-UN	5.875	16	0.0625	5.8344	0.0338	0.0156	5.8181	0.2°	5.8006	0.0203	16-UN	390
6 - 16 16-UN	6	16	0.0625	5.9594	0.0338	0.0156	5.9431	0.19°	5.9256	0.0203	16-UN	395
1/4 - 20 20-UN	0.25	20	0.0500	0.2175	0.0271	0.0125	0.2045	4.18°	0.1905	0.0162	20-UN	29
5/16 - 20 20-UN	0.312	20	0.0500	0.2795	0.0271	0.0125	0.2665	3.26°	0.2525	0.0162	20-UN	35
3/8 - 20 20-UN	0.375	20	0.0500	0.3425	0.0271	0.0125	0.3295	2.66°	0.3155	0.0162	20-UN	42
7/16 - 20 20-UN	0.437	20	0.0500	0.4045	0.0271	0.0125	0.3915	2.25°	0.3775	0.0162	20-UN	49
1/2 - 20 20-UN	0.5	20	0.0500	0.4675	0.0271	0.0125	0.4545	1.95°	0.4405	0.0162	20-UN	56
9/16 - 20 20-UN	0.562	20	0.0500	0.5295	0.0271	0.0125	0.5165	1.72°	0.5025	0.0162	20-UN	64
5/8 - 20 20-UN	0.625	20	0.0500	0.5925	0.0271	0.0125	0.5795	1.54°	0.5655	0.0162	20-UN	72
11/16 - 20 20-UN	0.687	20	0.0500	0.6545	0.0271	0.0125	0.6415	1.39°	0.6275	0.0162	20-UN	78
3/4 - 20 20-UN	0.75	20	0.0500	0.7175	0.0271	0.0125	0.7045	1.27°	0.6905	0.0162	20-UN	86
13/16 - 20 20-UN	0.812	20	0.0500	0.7795	0.0271	0.0125	0.7665	1.17°	0.7525	0.0162	20-UN	92
7/8 - 20 20-UN	0.875	20	0.0500	0.8425	0.0271	0.0125	0.8295	1.08°	0.8155	0.0162	20-UN	100
15/16 - 20 20-UN	0.937	20	0.0500	0.9045	0.0271	0.0125	0.8915	1.01°	0.8775	0.0162	20-UN	106
1 - 20 20-UN	1	20	0.0500	0.9675	0.0271	0.0125	0.9545	0.94°	0.9405	0.0162	20-UN	115
1 1/16 - 20 20-UN	1.062	20	0.0500	1.0295	0.0271	0.0125	1.0165	0.89°	1.0025	0.0162	20-UN	122
1 1/8 - 20 20-UN	1.125	20	0.0500	1.0925	0.0271	0.0125	1.0795	0.83°	1.0655	0.0162	20-UN	130
1 3/16 - 20 20-UN	1.187	20	0.0500	1.1545	0.0271	0.0125	1.1415	0.79°	1.1275	0.0162	20-UN	136
1 1/4 - 20 20-UN	1.25	20	0.0500	1.2175	0.0271	0.0125	1.2045	0.75°	1.1905	0.0162	20-UN	144
1 5/16 - 20 20-UN	1.312	20	0.0500	1.2795	0.0271	0.0125	1.2665	0.71°	1.2525	0.0162	20-UN	150
1 3/8 - 20 20-UN	1.375	20	0.0500	1.3425	0.0271	0.0125	1.3295	0.68°	1.3155	0.0162	20-UN	159
1 7/16 - 20 20-UN	1.437	20	0.0500	1.4045	0.0271	0.0125	1.3915	0.65°	1.3775	0.0162	20-UN	166
1 1/2 - 20 20-UN	1.5	20	0.0500	1.4675	0.0271	0.0125	1.4545	0.62°	1.4405	0.0162	20-UN	175
1 9/16 - 20 20-UN	1.562	20	0.0500	1.5295	0.0271	0.0125	1.5165	0.6°	1.5025	0.0162	20-UN	182
1 5/8 - 20 20-UN	1.625	20	0.0500	1.5925	0.0271	0.0125	1.5795	0.57°	1.5655	0.0162	20-UN	188
1 11/16 - 20 20-UN	1.687	20	0.0500	1.6545	0.0271	0.0125	1.6415	0.55°	1.6275	0.0162	20-UN	194
1 3/4 - 20 20-UN	1.75	20	0.0500	1.7175	0.0271	0.0125	1.7045	0.53°	1.6905	0.0162	20-UN	200
1 13/16 - 20 20-UN	1.812	20	0.0500	1.7795	0.0271	0.0125	1.7665	0.51°	1.7525	0.0162	20-UN	205
1 7/8 - 20 20-UN	1.875	20	0.0500	1.8425	0.0271	0.0125	1.8295	0.49°	1.8155	0.0162	20-UN	210
1 15/16 - 20 20-UN	1.937	20	0.0500	1.9045	0.0271	0.0125	1.8915	0.48°	1.8775	0.0162	20-UN	215
2 - 20 20-UN	2	20	0.0500	1.9675	0.0271	0.0125	1.9545	0.46°	1.9405	0.0162	20-UN	221
2 1/8 - 20 20-UN	2.125	20	0.0500	2.0925	0.0271	0.0125	2.0795	0.44°	2.0655	0.0162	20-UN	226
2 1/4 - 20 20-UN	2.25	20	0.0500	2.2175	0.0271	0.0125	2.2045	0.41°	2.1905	0.0162	20-UN	232
2 3/8 - 20 20-UN	2.375	20	0.0500	2.3425	0.0271	0.0125	2.3295	0.39°	2.3155	0.0162	20-UN	237
2 1/2 - 20 20-UN	2.5	20	0.0500	2.4675	0.0271	0.0125	2.4545	0.37°	2.4405	0.0162	20-UN	244
2 5/8 - 20 20-UN	2.625	20	0.0500	2.5925	0.0271	0.0125	2.5795	0.35°	2.5655	0.0162	20-UN	250
2 3/4 - 20 20-UN	2.75	20	0.0500	2.7175	0.0271	0.0125	2.7045	0.34°	2.6905	0.0162	20-UN	257
2 7/8 - 20 20-UN	2.875	20	0.0500	2.8425	0.0271	0.0125	2.8295	0.32°	2.8155	0.0162	20-UN	263
3 - 20 20-UN	3	20	0.0500	2.9675	0.0271	0.0125	2.9545	0.31°	2.9405	0.0162	20-UN	270
4 5/8 - 20-UN	4.625	20	0.0500	4.5925	0.0271	0.0125	4.5795	0.2°	4.5655	0.0162	20-UN	340
#12 - 28 28-UN	0.216	28	0.0357	0.1928	0.0193	0.0089	0.1835	3.37°	0.1735	0.0116	28-UN	24
1/4 - 28 28-UN	0.25	28	0.0357	0.2268	0.0193	0.0089	0.2175	2.87°	0.2075	0.0116	28-UN	30
5/16 - 28 28-UN	0.312	28	0.0357	0.2888	0.0193	0.0089	0.2795	2.25°	0.2695	0.0116	28-UN	36
3/8 - 28 28-UN	0.375	28	0.0357	0.3518	0.0193	0.0089	0.3425	1.85°	0.3325	0.0116	28-UN	43
7/16 - 28 28-UN	0.437	28	0.0357	0.4138	0.0193	0.0089	0.4045	1.57°	0.3945	0.0116	28-UN	50
1/2 - 28 28-UN	0.5	28	0.0357	0.4768	0.0193	0.0089	0.4675	1.37°	0.4575	0.0116	28-UN	57
9/16 - 28 28-UN	0.562	28	0.0357	0.5388	0.0193	0.0089	0.5295	1.21°	0.5195	0.0116	28-UN	65
5/8 - 28 28-UN	0.625	28	0.0357	0.6018	0.0193	0.0089	0.5925	1.08°	0.5825	0.0116	28-UN	73
11/16 - 28 28-UN	0.687	28	0.0357	0.6638	0.0193	0.0089	0.6545	0.98°	0.6445	0.0116	28-UN	79
3/4 - 28 28-UN	0.75	28	0.0357	0.7268	0.0193	0.0089	0.7175	0.9°	0.7075	0.0116	28-UN	87
13/16 - 28 28-UN	0.812	28	0.0357	0.7888	0.0193	0.0089	0.7795	0.83°	0.7695	0.0116	28-UN	93
7/8 - 28 28-UN	0.875	28	0.0357	0.8518	0.0193	0.0089	0.8425	0.76°	0.8325	0.0116	28-UN	101
15/16 - 28 28-UN	0.937	28	0.0357	0.9138	0.0193	0.0089	0.9045	0.71°	0.8945	0.0116	28-UN	107
1 - 28 28-UN	1	28	0.0357	0.9768	0.0193	0.0089	0.9675	0.67°	0.9575	0.0116	28-UN	116
1 1/16 - 28 28-UN	1.062	28	0.0357	1.0388	0.0193	0.0089	1.0295	0.63°	1.0195	0.0116	28-UN	123
1 1/8 - 28 28-UN	1.125	28	0.0357	1.1018	0.0193	0.0089	1.0925	0.59°	1.0825	0.0116	28-UN	131
1 3/16 - 28 28-UN	1.187	28	0.0357	1.1638	0.0193	0.0089	1.1545	0.56°	1.1445	0.0116	28-UN	137
1 1/4 - 28 28-UN	1.25	28	0.0357	1.2268	0.0193	0.0089	1.2175	0.53°	1.2075	0.0116	28-UN	145
1 5/16 - 28 28-UN	1.312	28	0.0357	1.2888	0.0193	0.0089	1.2795	0.51°	1.2695	0.0116	28-UN	151
1 3/8 - 28 28-UN	1.375	28	0.0357	1.3518	0.0193	0.0089	1.3425	0.48°	1.3325	0.0116	28-UN	160
1 7/16 - 28 28-UN	1.437	28	0.0357	1.4138	0.0193	0.0089	1.4045	0.46°	1.3945	0.0116	28-UN	167
1 1/2 - 28 28-UN	1.5	28	0.0357	1.4768	0.0193	0.0089	1.4675	0.44°	1.4575	0.0116	28-UN	176
#6 - 32 32-UN	0.138	32	0.0313	0.1177	0.0169	0.0078	0.1096	4.83°	0.1008	0.0101	32-UN	14
#8 - 32 32-UN	0.164	32	0.0313	0.1437	0.0169	0.0078	0.1356	3.96°	0.1268	0.0101	32-UN	17
#10 - 32 32-UN	0.19	32	0.0313	0.1697	0.0169	0.0078	0.1616	3.35°	0.1528	0.0101	32-UN	20
#12 - 32 32-UN	0.216	32	0.0313	0.1957	0.0169	0.0078	0.1876	2.91°	0.1788	0.0101	32-UN	25
1/4 - 32 32-UN	0.25	32	0.0313	0.2297	0.0169	0.0078	0.2216	2.48°	0.2128	0.0101	32-UN	31
5/16 - 32 32-UN	0.312	32	0.0313	0.2917	0.0169	0.0078	0.2836	1.95°	0.2748	0.0101	32-UN	37
3/8 - 32 32-UN	0.375	32	0.0313	0.3547	0.0169	0.0078	0.3466	1.61°	0.3378	0.0101	32-UN	44
7/16 - 32 32-UN	0.437	32	0.0313	0.4167	0.0169	0.0078	0.4086	1.37°	0.3998	0.0101	32-UN	51
1/2 - 32 32-UN	0.5	32	0.0313	0.4797	0.0169	0.0078	0.4716	1.19°	0.4628	0.0101	32-UN	58
9/16 - 32 32-UN	0.562	32	0.0313	0.5417	0.0169	0.0078	0.5336	1.05°	0.5248	0.0101	32-UN	66
5/8 - 32 32-UN	0.625	32	0.0313	0.6047	0.0169	0.0078	0.5966	0.94°	0.5878	0.0101	32-UN	74
11/16 - 32 32-UN	0.687	32	0.0313	0.6667	0.0169	0.0078	0.6586	0.85°	0.6498	0.0101	32-UN	80
3/4 - 32 32-UN	0.75	32	0.0313	0.7297	0.0169	0.0078	0.7216	0.78°	0.7128	0.0101	32-UN	88
13/16 - 32 32-UN	0.812	32	0.0313	0.7917	0.0169	0.0078	0.7836	0.72°	0.7748	0.0101	32-UN	94
7/8 - 32 32-UN	0.875	32	0.0313	0.8547	0.0169	0.0078	0.8466	0.67°	0.8378	0.0101	32-UN	102
15/16 - 32 32-UN	0.937	32	0.0313	0.9167	0.0169	0.0078	0.9086	0.62°	0.8998	0.0101	32-UN	108
1 - 32 32-UN	1	32	0.0313	0.9797	0.0169	0.0078	0.9716	0.58°	0.9628	0.0101	32-UN	117
2 1/2 - 4 4-UN	2.5	4	0.2500	2.3376	0.1353	0.0625	2.2725	1.95°	2.2023	0.0812	4-UN	239
2 5/8 - 4 4-UN	2.625	4	0.2500	2.4626	0.1353	0.0625	2.3975	1.85°	2.3273	0.0812	4-UN	245
2 3/4 - 4 4-UN	2.75	4	0.2500	2.5876	0.1353	0.0625	2.5225	1.76°	2.4523	0.0812	4-UN	252
2 7/8 - 4 4-UN	2.875	4	0.2500	2.7126	0.1353	0.0625	2.6475	1.68°	2.5773	0.0812	4-UN	258
3 - 4 4-UN	3	4	0.2500	2.8376	0.1353	0.0625	2.7725	1.61°	2.7023	0.0812	4-UN	265
3 1/8 - 4 4-UN	3.125	4	0.2500	2.9626	0.1353	0.0625	2.8975	1.54°	2.8273	0.0812	4-UN	271
3 1/4 - 4 4-UN	3.25	4	0.2500	3.0876	0.1353	0.0625	3.0225	1.48°	2.9523	0.0812	4-UN	277
3 3/8 - 4 4-UN	3.375	4	0.2500	3.2126	0.1353	0.0625	3.1475	1.42°	3.0773	0.0812	4-UN	282
3 1/2 - 4 4-UN	3.5	4	0.2500	3.3376	0.1353	0.0625	3.2725	1.37°	3.2023	0.0812	4-UN	288
3 5/8 - 4 4-UN	3.625	4	0.2500	3.4626	0.1353	0.0625	3.3975	1.32°	3.3273	0.0812	4-UN	293
3 3/4 - 4 4-UN	3.75	4	0.2500	3.5876	0.1353	0.0625	3.5225	1.27°	3.4523	0.0812	4-UN	299
3 7/8 - 4 4-UN	3.875	4	0.2500	3.7126	0.1353	0.0625	3.6475	1.23°	3.5773	0.0812	4-UN	304
4 - 4 4-UN	4	4	0.2500	3.8376	0.1353	0.0625	3.7725	1.19°	3.7023	0.0812	4-UN	310
4 1/8 - 4 4-UN	4.125	4	0.2500	3.9626	0.1353	0.0625	3.8975	1.15°	3.8273	0.0812	4-UN	315
4 1/4 - 4 4-UN	4.25	4	0.2500	4.0876	0.1353	0.0625	4.0225	1.12°	3.9523	0.0812	4-UN	320
4 3/8 - 4 4-UN	4.375	4	0.2500	4.2126	0.1353	0.0625	4.1475	1.08°	4.0773	0.0812	4-UN	325
4 1/2 - 4 4-UN	4.5	4	0.2500	4.3376	0.1353	0.0625	4.2725	1.05°	4.2023	0.0812	4-UN	330
4 5/8 - 4 4-UN	4.625	4	0.2500	4.4626	0.1353	0.0625	4.3975	1.02°	4.3273	0.0812	4-UN	335
4 3/4 - 4 4-UN	4.75	4	0.2500	4.5876	0.1353	0.0625	4.5225	0.99°	4.4523	0.0812	4-UN	341
4 7/8 - 4 4-UN	4.875	4	0.2500	4.7126	0.1353	0.0625	4.6475	0.97°	4.5773	0.0812	4-UN	346
5 - 4 4-UN	5	4	0.2500	4.8376	0.1353	0.0625	4.7725	0.94°	4.7023	0.0812	4-UN	351
5 1/8 - 4 4-UN	5.125	4	0.2500	4.9626	0.1353	0.0625	4.8975	0.92°	4.8273	0.0812	4-UN	356
5 1/4 - 4 4-UN	5.25	4	0.2500	5.0876	0.1353	0.0625	5.0225	0.9°	4.9523	0.0812	4-UN	361
5 3/8 - 4 4-UN	5.375	4	0.2500	5.2126	0.1353	0.0625	5.1475	0.87°	5.0773	0.0812	4-UN	366
5 1/2 - 4 4-UN	5.5	4	0.2500	5.3376	0.1353	0.0625	5.2725	0.85°	5.2023	0.0812	4-UN	371
5 5/8 - 4 4-UN	5.625	4	0.2500	5.4626	0.1353	0.0625	5.3975	0.83°	5.3273	0.0812	4-UN	376
5 3/4 - 4 4-UN	5.75	4	0.2500	5.5876	0.1353	0.0625	5.5225	0.82°	5.4523	0.0812	4-UN	381
5 7/8 - 4 4-UN	5.875	4	0.2500	5.7126	0.1353	0.0625	5.6475	0.8°	5.5773	0.0812	4-UN	386
6 - 4 4-UN	6	4	0.2500	5.8376	0.1353	0.0625	5.7725	0.78°	5.7023	0.0812	4-UN	391
1 3/8 - 6 6-UN	1.375	6	0.1667	1.2667	0.0902	0.0417	1.2233	2.4°	1.1765	0.0541	6-UN	155
1 7/16 - 6 6-UN	1.437	6	0.1667	1.3287	0.0902	0.0417	1.2853	2.29°	1.2385	0.0541	6-UN	162
1 1/2 - 6 6-UN	1.5	6	0.1667	1.3917	0.0902	0.0417	1.3483	2.18°	1.3015	0.0541	6-UN	171
1 9/16 - 6 6-UN	1.562	6	0.1667	1.4537	0.0902	0.0417	1.4103	2.09°	1.3635	0.0541	6-UN	178
1 5/8 - 6 6-UN	1.625	6	0.1667	1.5167	0.0902	0.0417	1.4733	2°	1.4265	0.0541	6-UN	184
1 11/16 - 6 6-UN	1.687	6	0.1667	1.5787	0.0902	0.0417	1.5353	1.92°	1.4885	0.0541	6-UN	190
1 3/4 - 6 6-UN	1.75	6	0.1667	1.6417	0.0902	0.0417	1.5983	1.85°	1.5515	0.0541	6-UN	196
1 13/16 - 6 6-UN	1.812	6	0.1667	1.7037	0.0902	0.0417	1.6603	1.78°	1.6135	0.0541	6-UN	201
1 7/8 - 6 6-UN	1.875	6	0.1667	1.7667	0.0902	0.0417	1.7233	1.72°	1.6765	0.0541	6-UN	206
1 15/16 - 6 6-UN	1.937	6	0.1667	1.8287	0.0902	0.0417	1.7853	1.66°	1.7385	0.0541	6-UN	211
2 - 6 6-UN	2	6	0.1667	1.8917	0.0902	0.0417	1.8483	1.61°	1.8015	0.0541	6-UN	217
2 1/8 - 6 6-UN	2.125	6	0.1667	2.0167	0.0902	0.0417	1.9733	1.51°	1.9265	0.0541	6-UN	222
2 1/4 - 6 6-UN	2.25	6	0.1667	2.1417	0.0902	0.0417	2.0983	1.42°	2.0515	0.0541	6-UN	228
2 3/8 - 6 6-UN	2.375	6	0.1667	2.2667	0.0902	0.0417	2.2233	1.34°	2.1765	0.0541	6-UN	233
2 1/2 - 6 6-UN	2.5	6	0.1667	2.3917	0.0902	0.0417	2.3483	1.27°	2.3015	0.0541	6-UN	240
2 5/8 - 6 6-UN	2.625	6	0.1667	2.5167	0.0902	0.0417	2.4733	1.21°	2.4265	0.0541	6-UN	246
2 3/4 - 6 6-UN	2.75	6	0.1667	2.6417	0.0902	0.0417	2.5983	1.15°	2.5515	0.0541	6-UN	253
2 7/8 - 6 6-UN	2.875	6	0.1667	2.7667	0.0902	0.0417	2.7233	1.1°	2.6765	0.0541	6-UN	259
3 - 6 6-UN	3	6	0.1667	2.8917	0.0902	0.0417	2.8483	1.05°	2.8015	0.0541	6-UN	266
3 1/8 - 6 6-UN	3.125	6	0.1667	3.0167	0.0902	0.0417	2.9733	1.01°	2.9265	0.0541	6-UN	272
3 1/4 - 6 6-UN	3.25	6	0.1667	3.1417	0.0902	0.0417	3.0983	0.97°	3.0515	0.0541	6-UN	278
3 3/8 - 6 6-UN	3.375	6	0.1667	3.2667	0.0902	0.0417	3.2233	0.93°	3.1765	0.0541	6-UN	283
3 1/2 - 6 6-UN	3.5	6	0.1667	3.3917	0.0902	0.0417	3.3483	0.9°	3.3015	0.0541	6-UN	289
3 5/8 - 6 6-UN	3.625	6	0.1667	3.5167	0.0902	0.0417	3.4733	0.86°	3.4265	0.0541	6-UN	294
3 3/4 - 6 6-UN	3.75	6	0.1667	3.6417	0.0902	0.0417	3.5983	0.83°	3.5515	0.0541	6-UN	300
3 7/8 - 6 6-UN	3.875	6	0.1667	3.7667	0.0902	0.0417	3.7233	0.81°	3.6765	0.0541	6-UN	305
4 - 6 6-UN	4	6	0.1667	3.8917	0.0902	0.0417	3.8483	0.78°	3.8015	0.0541	6-UN	311
4 1/8 - 6 6-UN	4.125	6	0.1667	4.0167	0.0902	0.0417	3.9733	0.76°	3.9265	0.0541	6-UN	316
4 1/4 - 6 6-UN	4.25	6	0.1667	4.1417	0.0902	0.0417	4.0983	0.73°	4.0515	0.0541	6-UN	321
4 3/8 - 6 6-UN	4.375	6	0.1667	4.2667	0.0902	0.0417	4.2233	0.71°	4.1765	0.0541	6-UN	326
4 1/2 - 6 6-UN	4.5	6	0.1667	4.3917	0.0902	0.0417	4.3483	0.69°	4.3015	0.0541	6-UN	331
4 5/8 - 6 6-UN	4.625	6	0.1667	4.5167	0.0902	0.0417	4.4733	0.67°	4.4265	0.0541	6-UN	336
4 3/4 - 6 6-UN	4.75	6	0.1667	4.6417	0.0902	0.0417	4.5983	0.65°	4.5515	0.0541	6-UN	342
4 7/8 - 6 6-UN	4.875	6	0.1667	4.7667	0.0902	0.0417	4.7233	0.64°	4.6765	0.0541	6-UN	347
5 - 6 6-UN	5	6	0.1667	4.8917	0.0902	0.0417	4.8483	0.62°	4.8015	0.0541	6-UN	352
5 1/8 - 6 6-UN	5.125	6	0.1667	5.0167	0.0902	0.0417	4.9733	0.61°	4.9265	0.0541	6-UN	357
5 1/4 - 6 6-UN	5.25	6	0.1667	5.1417	0.0902	0.0417	5.0983	0.59°	5.0515	0.0541	6-UN	362
5 3/8 - 6 6-UN	5.375	6	0.1667	5.2667	0.0902	0.0417	5.2233	0.58°	5.1765	0.0541	6-UN	367
5 1/2 - 6 6-UN	5.5	6	0.1667	5.3917	0.0902	0.0417	5.3483	0.56°	5.3015	0.0541	6-UN	372
5 5/8 - 6 6-UN	5.625	6	0.1667	5.5167	0.0902	0.0417	5.4733	0.55°	5.4265	0.0541	6-UN	377
5 3/4 - 6 6-UN	5.75	6	0.1667	5.6417	0.0902	0.0417	5.5983	0.54°	5.5515	0.0541	6-UN	382
5 7/8 - 6 6-UN	5.875	6	0.1667	5.7667	0.0902	0.0417	5.7233	0.53°	5.6765	0.0541	6-UN	387
6 - 6 6-UN	6	6	0.1667	5.8917	0.0902	0.0417	5.8483	0.52°	5.8015	0.0541	6-UN	392
1 - 8 8-UN	1	8	0.1250	0.9188	0.0677	0.0313	0.8863	2.48°	0.8512	0.0406	8-UN	112
1 1/16 - 8 8-UN	1.062	8	0.1250	0.9808	0.0677	0.0313	0.9483	2.32°	0.9132	0.0406	8-UN	119
1 1/8 - 8 8-UN	1.125	8	0.1250	1.0438	0.0677	0.0313	1.0113	2.18°	0.9762	0.0406	8-UN	127
1 3/16 - 8 8-UN	1.187	8	0.1250	1.1058	0.0677	0.0313	1.0733	2.06°	1.0382	0.0406	8-UN	133
1 1/4 - 8 8-UN	1.25	8	0.1250	1.1688	0.0677	0.0313	1.1363	1.95°	1.1012	0.0406	8-UN	141
1 5/16 - 8 8-UN	1.312	8	0.1250	1.2308	0.0677	0.0313	1.1983	1.85°	1.1632	0.0406	8-UN	147
1 3/8 - 8 8-UN	1.375	8	0.1250	1.2938	0.0677	0.0313	1.2613	1.76°	1.2262	0.0406	8-UN	156
1 7/16 - 8 8-UN	1.437	8	0.1250	1.3558	0.0677	0.0313	1.3233	1.68°	1.2882	0.0406	8-UN	163
1 1/2 - 8 8-UN	1.5	8	0.1250	1.4188	0.0677	0.0313	1.3863	1.61°	1.3512	0.0406	8-UN	172
1 9/16 - 8 8-UN	1.562	8	0.1250	1.4808	0.0677	0.0313	1.4483	1.54°	1.4132	0.0406	8-UN	179
1 5/8 - 8 8-UN	1.625	8	0.1250	1.5438	0.0677	0.0313	1.5113	1.48°	1.4762	0.0406	8-UN	185
1 11/16 - 8 8-UN	1.687	8	0.1250	1.6058	0.0677	0.0313	1.5733	1.42°	1.5382	0.0406	8-UN	191
1 3/4 - 8 8-UN	1.75	8	0.1250	1.6688	0.0677	0.0313	1.6363	1.37°	1.6012	0.0406	8-UN	197
1 13/16 - 8 8-UN	1.812	8	0.1250	1.7308	0.0677	0.0313	1.6983	1.32°	1.6632	0.0406	8-UN	202
1 7/8 - 8 8-UN	1.875	8	0.1250	1.7938	0.0677	0.0313	1.7613	1.27°	1.7262	0.0406	8-UN	207
1 15/16 - 8 8-UN	1.937	8	0.1250	1.8558	0.0677	0.0313	1.8233	1.23°	1.7882	0.0406	8-UN	212
2 - 8 8-UN	2	8	0.1250	1.9188	0.0677	0.0313	1.8863	1.19°	1.8512	0.0406	8-UN	218
2 1/8 - 8 8-UN	2.125	8	0.1250	2.0438	0.0677	0.0313	2.0113	1.12°	1.9762	0.0406	8-UN	223
2 1/4 - 8 8-UN	2.25	8	0.1250	2.1688	0.0677	0.0313	2.1363	1.05°	2.1012	0.0406	8-UN	229
2 3/8 - 8 8-UN	2.375	8	0.1250	2.2938	0.0677	0.0313	2.2613	0.99°	2.2262	0.0406	8-UN	234
2 1/2 - 8 8-UN	2.5	8	0.1250	2.4188	0.0677	0.0313	2.3863	0.94°	2.3512	0.0406	8-UN	241
2 5/8 - 8 8-UN	2.625	8	0.1250	2.5438	0.0677	0.0313	2.5113	0.9°	2.4762	0.0406	8-UN	247
2 3/4 - 8 8-UN	2.75	8	0.1250	2.6688	0.0677	0.0313	2.6363	0.85°	2.6012	0.0406	8-UN	254
2 7/8 - 8 8-UN	2.875	8	0.1250	2.7938	0.0677	0.0313	2.7613	0.82°	2.7262	0.0406	8-UN	260
3 - 8 8-UN	3	8	0.1250	2.9188	0.0677	0.0313	2.8863	0.78°	2.8512	0.0406	8-UN	267
3 1/8 - 8 8-UN	3.125	8	0.1250	3.0438	0.0677	0.0313	3.0113	0.75°	2.9762	0.0406	8-UN	273
3 1/4 - 8 8-UN	3.25	8	0.1250	3.1688	0.0677	0.0313	3.1363	0.72°	3.1012	0.0406	8-UN	279
3 3/8 - 8 8-UN	3.375	8	0.1250	3.2938	0.0677	0.0313	3.2613	0.69°	3.2262	0.0406	8-UN	284
3 1/2 - 8 8-UN	3.5	8	0.1250	3.4188	0.0677	0.0313	3.3863	0.67°	3.3512	0.0406	8-UN	290
3 5/8 - 8 8-UN	3.625	8	0.1250	3.5438	0.0677	0.0313	3.5113	0.64°	3.4762	0.0406	8-UN	295
3 3/4 - 8 8-UN	3.75	8	0.1250	3.6688	0.0677	0.0313	3.6363	0.62°	3.6012	0.0406	8-UN	301
3 7/8 - 8 8-UN	3.875	8	0.1250	3.7938	0.0677	0.0313	3.7613	0.6°	3.7262	0.0406	8-UN	306
4 - 8 8-UN	4	8	0.1250	3.9188	0.0677	0.0313	3.8863	0.58°	3.8512	0.0406	8-UN	312
4 1/8 - 8 8-UN	4.125	8	0.1250	4.0438	0.0677	0.0313	4.0113	0.56°	3.9762	0.0406	8-UN	317
4 1/4 - 8 8-UN	4.25	8	0.1250	4.1688	0.0677	0.0313	4.1363	0.55°	4.1012	0.0406	8-UN	322
4 3/8 - 8 8-UN	4.375	8	0.1250	4.2938	0.0677	0.0313	4.2613	0.53°	4.2262	0.0406	8-UN	327
4 1/2 - 8 8-UN	4.5	8	0.1250	4.4188	0.0677	0.0313	4.3863	0.52°	4.3512	0.0406	8-UN	332
4 5/8 - 8 8-UN	4.625	8	0.1250	4.5438	0.0677	0.0313	4.5113	0.5°	4.4762	0.0406	8-UN	337
4 3/4 - 8 8-UN	4.75	8	0.1250	4.6688	0.0677	0.0313	4.6363	0.49°	4.6012	0.0406	8-UN	343
4 7/8 - 8 8-UN	4.875	8	0.1250	4.7938	0.0677	0.0313	4.7613	0.48°	4.7262	0.0406	8-UN	348
5 - 8 8-UN	5	8	0.1250	4.9188	0.0677	0.0313	4.8863	0.46°	4.8512	0.0406	8-UN	353
5 1/8 - 8 8-UN	5.125	8	0.1250	5.0438	0.0677	0.0313	5.0113	0.45°	4.9762	0.0406	8-UN	358
5 1/4 - 8 8-UN	5.25	8	0.1250	5.1688	0.0677	0.0313	5.1363	0.44°	5.1012	0.0406	8-UN	363
5 3/8 - 8 8-UN	5.375	8	0.1250	5.2938	0.0677	0.0313	5.2613	0.43°	5.2262	0.0406	8-UN	368
5 1/2 - 8 8-UN	5.5	8	0.1250	5.4188	0.0677	0.0313	5.3863	0.42°	5.3512	0.0406	8-UN	373
5 5/8 - 8 8-UN	5.625	8	0.1250	5.5438	0.0677	0.0313	5.5113	0.41°	5.4762	0.0406	8-UN	378
5 3/4 - 8 8-UN	5.75	8	0.1250	5.6688	0.0677	0.0313	5.6363	0.4°	5.6012	0.0406	8-UN	383
5 7/8 - 8 8-UN	5.875	8	0.1250	5.7938	0.0677	0.0313	5.7613	0.39°	5.7262	0.0406	8-UN	388
6 - 8 8-UN	6	8	0.1250	5.9188	0.0677	0.0313	5.8863	0.39°	5.8512	0.0406	8-UN	393

limits of Thread Dimensions (UNC, UNF & UNEF)

To manufacture or measure a thread, one has to know the maximum and minimum permissible values of the basic dimensions. These values are calculated according to the thread class (See below). To understand classes, you first need to understand the terms Allowance (Sometimes referred to as deviation) and Tolerances.

Definition of terms:

Allowance (Deviation): The minimum permissible distance between the basic and actual profile.
Tolerance: The width of the tolerance field of a diameter on the actual thread profile. (Pitch, Major & Minor diameters)

A small allowance means that the assembly of a male and female thread will be harder, but after assembly, there will be less freedom of movement.
A large allowance means that the assembly of a male and female thread will be easier, but after assembly, there will be more freedom of movement.
The allowance size does not influence a thread’s production difficulty or price.
A wide tolerance is easier and cheaper to produce but yields a larger spread between threads.
A narrow tolerance is challenging to produce and more expensive but yields a smaller spread between threads.

Unified Thread Classes

The class is defined by a two-character code.
- The first character defines is a digit between 1 and 3. 1=Loose fit, 2=Medium fit, and 3=Tight fit.
- The second character is a letter. A=External thread and B=Internal thread.

In the Unified Inch thread system, only classes 1A & 2A have an allowance. The allowance for the two classes is the same.
The other 4 classes have an allowance of Zero.
All the internal thread profiles (B classes) have no allowance.

Classes 1A & 1B: These classes are suitable for applications where a liberal tolerance and allowance are required to permit easy assembly. The maximum diameters of Class 1A threads are smaller than the basic diameter by the allowance amount. The minimum diameters of Class 1B threads are equal to the basic diameters and consequently afford no allowance at maximum material condition.
Classes 2A & 2B: Classes 2A (external) and 2B (internal) are the default classes used for the commercial production of Nut, Bols, and otehr threaded fasteners. They are the default class unless otherwise specified. they have the same allowance as classes 1A/1B. However, they have a narrower tolerance field. The difficulty of assembly is the same, but the spread between different parts in a production batch is smaller.
Classes 3A & 3B: These classes are suitable for applications where tight fit and accuracy of thread elements are essential. The maximum diameters of Class 3A threads and the minimum diameters of Class 3B threads are the same (Both have zero allowance). The accuracy is high, but the assembly is difficult.
Combinations of Classes: The engineer can select any valid class for the male and female threads to achieve his design goals. The valid classes are defined in ASTM B1.1 as follows:
- Classes 2A, 2A, 3B, and 3B are always valid.
- Classes 1A & 1B are valid only for UNC threads with a nominal diameter equal to or larger than 1/4″.

Unified Thread Allowance.

The allowance es should be calculated for external threads with classes 1A and 2A. The allowance of both classes is the same and equals 0.3 times the pitch diameter tolerance of class 2A. It is the function of 3 parameters.

D – Basic (nominal diameter)
P – Pitch (1/TPI)
LE – Length of engagement. If not explicitly specified, the length of engagement is assumed to be 5 pitches. (LE=5*P)
All parameters are in inches

\( \large es = 0.3 \times \left [ 0.0015 \times \sqrt[3]{D} + 0.0015 \times \sqrt{LE} + 0.015 \times \sqrt[3]{P^{2}} \right ] \)

\begin{array} \large \,es& = 0.3 \times\,[\,0.0015 \times \sqrt[3]{D} &\\ & +\,0.0015 \times \sqrt{LE}&\\ & + 0.015 \times \sqrt[3]{P^{2}}\,] \end{array}

The result should be rounded to 6 decimal places.
ASTM B1.1 lists in a long chart the allowance for each thread size. However, the results of this formula are 100% accurate, and there is no need to browse the chart.
You can use our Advanced Threading Calculator to obtain the allowance according to a thread description or use the mini-calculator below.

Unified Thread Allowance Calculator

Unified Thread Tolerances

The tolerances T_D for internal threads and T_d for external threads are derived from the class. The tolerances can be calculated according to the below formulas.

T_d – Tolerance for External Major Diameter
T_d2 – Tolerance for External Pitch Diameter
T_D1 – Tolerance for Internal Minor Diameter
T_D2 – Tolerance for Internal Pitch Diameter
T – Base Tolerance (The tolerance of CLASS 2A pitch diameter is the base tolerance from which other tolerances are derived)
D – Basic thread diameter.
P – Pitch (1/TPI).
LE – Length of engagement. (If unknown, the default is 5 * P)
All input parameters and results are in Inches.

Base Tolerance Formula

\( \large T = 0.0015 \times \sqrt[3]{D} + 0.0015 \times \sqrt{LE} + 0.015 \times \sqrt[3]{P^{2}}\)

\begin{array} \large \,T& = \,0.0015 \times \sqrt[3]{D} &\\ & +\,0.0015 \times \sqrt{LE}&\\ & + 0.015 \times \sqrt[3]{P^{2}} \end{array}

Formulas for External thread
(Classes 1A,2A & 3A)

\( \large T_{d(1A)} = 0.3 \times T \)

\( \large T_{d2(1A)} = 1.5 \times T \)

\( \large T_{d(2A)} = 0.06 \times \sqrt[3]{P^2} \)

\( \large T_{d2(2A)} = T \)

\( \large T_{d(3A)} = 0.06 \times \sqrt[3]{P^2} \)

\( \large T_{d2(3A)} = 0.75 \times T \)

Formulas for Internal Thread
(Classes 1B,2B & 3B)

\( \large T_{d1(1B)} = 0.25 \times P\,-\,0.4 \times P^{2} \)

\( \large T_{d2(1B)} = 1.95 \times T \)

\( \large T_{d1(2B)} = 0.25 \times P\,-\,0.4 \times P^{2} \)

\( \large T_{d2(2B)} = 1.30 \times T \)

\(\begin{array}{ll} \large T_{d1(3B)}=&0.05 \times \sqrt[3]{P} + &\\ &0.003 \times \frac{P}{D}\,-\,0.002 \end{array} \)

\( \large T_{d2(3B)} = 0.975 \times T \)

The above formulas can be used in most cases. However, ASTM B1.1 lists various scenarios where other formulas or quirky rounding rules apply. Use our Advanced Threading Calculator to get exact results for any thread.

Usage notes for the above formulas:

The result should be rounded to 6 decimal places.
Formulas for external threads are valid for all threads.
Formulas for internal threads are valid only for thread diameters above 1/4″, a pitch between 4 and 80 TPI, and engagement lengths up to 1.5 X D.
In some cases, ASTM B1.1 dictates special rounding rules.
You can use the Threading Calculator, which automatically considers all the above rules.

Unified Thread limits Calculations

Once the T_d, T_D, & es values are known, the final limits can be calculated according to the formulas below.

Formulas for Limits of a Unified Inch External Thread

Unified Inch Thread external tolerances sketch

\( \large d_{max}=d-{es} \)
\( \large d_{min}=d_{max}-T_d \)
\( \large d_{2max} = d2 – es \)
\( \large d_{2min}=d_{2max}-T_{d2} \)

Formulas for Limits of a Unified Inch InternalThread

Unified Inch Thread internal tolerances sketch

\( \large D_{1min}=D \)
\( \large D_{1max}=D_{1min}+T_{D1} \)
\( \large D_{2minx} = D_2 \)
\( \large D_{2max}=D_{2min}+ T_{D2} \)

Related Glossary Terms:

SpeeDoctor

ThreaDoctor

Each Data-Sheet Includes:

Convert material standards:

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Each Data-Sheet Includes:

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Unified Screw Threads (UNC/UNF/UNEF): Charts & Formulas

List of Charts

Overview