| Bolt Diameter (mm) |
Head/Wrench Size (mm) |
|||
|---|---|---|---|---|
| ANSI/ISO | DIN | JIS | DIN/ISO Heavy Hex |
|
| 4 | 7 | 7 | 7 | – |
| 5 | 8 | 8 | 8 | – |
| 6 | 10 | 10 | 10 | – |
| 7 | – | 11 | – | – |
| 8 | 13 | 13 | 12 | – |
| 10 | 16 | 17 | 14 | – |
| 12 | 18 | 19 | 17 | 22/21* |
| 14 | 21 | 22 | 19 | – |
| 16 | 24 | 24 | 22 | 27 |
| 18 | – | 27 | – | – |
| 20 | 30 | 30 | – | 34/32* |
| ANSI – American National Standards Institute ISO – International Organization for Standardisation DIN – Deutsches Institut fur Normung JIS – Japanese Industrial Standard * Indicates ISO standard. |
||||
Tag: Threaded Joints
National Pipe Thread (NPT) Sizes / Dimensions
Pipe thread sizes
| Nominal NPT Size |
Outer Diameter inch (mm) |
Threads per inch |
Pitch of Thread inch (mm) |
|---|---|---|---|
| 1/16“ | 0.3125 in (7.94 mm) | 27 | 0.03704 in (0.94082 mm) |
| ⅛” | 0.405 in (10.29 mm) | 27 | 0.03704 in (0.94082 mm) |
| ¼” | 0.540 in (13.72 mm) | 18 | 0.05556 in (1.41122 mm) |
| 3/8″ | 0.675 in (17.15 mm) | 18 | 0.05556 in (1.41122 mm) |
| ½” | 0.840 in (21.34 mm) | 14 | 0.07143 in (1.81432 mm) |
| ¾” | 1.050 in (26.67 mm) | 14 | 0.07143 in (1.81432 mm) |
| 1″ | 1.315 in (33.40 mm) | 11½ | 0.08696 in (2.20878 mm) |
| 1¼” | 1.660 in (42.16 mm) | 11½ | 0.08696 in (2.20878 mm) |
| 1½” | 1.900 in (48.26 mm) | 11½ | 0.08696 in (2.20878 mm) |
| 2″ | 2.375 in (60.33 mm) | 11½ | 0.08696 in (2.20878 mm) |
| 2½” | 2.875 in (73.02 mm) | 8 | 0.12500 in (3.175 mm) |
| 3″ | 3.500 in (88.90 mm) | 8 | 0.12500 in (3.175 mm) |
| 4″ | 4.500 in (114.30 mm) | 8 | 0.12500 in (3.175 mm) |
| 5″ | 5.563 in (141.30 mm) | 8 | 0.12500 in (3.175 mm) |
| 6″ | 6.625 in (168.27 mm) | 8 | 0.12500 in (3.175 mm) |
| 10″ | 10.750 in (273.05 mm) | 8 | 0.12500 in (3.175 mm) |
| 12″ | 12.750 in (323.85 mm) | 8 | 0.12500 in (3.175 mm) |
| 14″ OD | 14 in (355.60 mm) | 8 | 0.12500 in (3.175 mm) |
| 16″ OD | 16 in (406.40 mm) | 8 | 0.12500 in (3.175 mm) |
| 18″ OD | 18 in (457.20 mm) | 8 | 0.12500 in (3.175 mm) |
| 20″ OD | 20 in (508.00 mm) | 8 | 0.12500 in (3.175 mm) |
| 24″ OD | 24 in (609.60 mm) | 8 | 0.12500 in (3.175 mm) |
| Definition of pipe thread acronyms | |
| NPT | National Pipe Thread |
| FPT | Female Pipe Thread |
| MPT | Male Pipe Thread |
| PTF | SAE short taper pipe thread – dryseal |
| NPTF | American National taper pipe thread for dryseal pressure-tight joints |
| NPSM | American National straight pipe thread for mechanical joints |
| NPSI | American National straight intermediate pipe thread |
| GHT | Garden Hose Thread |
| NST | Fire Hose Thread |
| BSPT | British Standard taper pipe thread (metric dimensions) |
Hex Nut Grade Identification and Mechanical Properties
| Grade Identification Marking |
Specification | Material | Nominal Size In. |
Proof Load Stress ksi |
Hardness Rockwell |
See Note |
|
| Min | Max | ||||||
 No Mark |
ASTM A563 – Grade 0 | Carbon Steel | 1/4 thru 1-1/2 | 69 | B55 | C32 | 3,4 |
| ASTM A563 – Grade A | Carbon Steel | 1/4 thru 1-1/2 | 90 | B68 | C32 | 3,4 | |
| ASTM A563 – Grade B | Carbon Steel | 1/4 thru 1 | 120 | B69 | C32 | 3,4 | |
| over 1 thru 1-1/2 | 105 | ||||||
 |
ASTM A563 – Grade C | Carbon Steel May be Quenched and Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5 |
 |
ASTM A563 – Grade C3 | Atmospheric Corrosion Resistant Steel May be Quenched and Tampered |
1/4 thru 4 | 144 | B78 | C38 | 5,9 |
 |
ASTM A563 – Grade D | Carbon Steel May be Quenched and Tampered |
1/4 thru 4 | 150 | B84 | C38 | 6 |
 |
ASTM A563 – Grade DH | Carbon Steel Quenched and Tampered |
1/4 thru 4 | 175 | C24 | C38 | 6 |
 |
ASTM A563 – Grade DH3 | Atmospheric Corrosion Resistant Steel, Quenched and Tampered |
1/4 thru 4 | 175 | C24 | C38 | 5,9 |
 |
ASTM A194 – Grade 1 | Carbon Steel | 1/4 thru 4 | 130 | B70 | — | 7 |
 |
ASTM A194 – Grade 2 | Medium Carbon Steel |
1/4 thru 4 | 150 | 159 | 352 | 7,8 |
 |
ASTM A194 – Grade 2H | Medium Carbon Steel, Quenched and Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 2HM | Medium Carbon Steel, Quenched and Tempered |
1/4 thru 4 | 150 | 159 | 237 | 7,8 |
 |
ASTM A194 – Grade 4 | Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 7 | Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 175 | C24 | C38 | 7 |
 |
ASTM A194 – Grade 7M | Medium Carbon Alloy Steel, Quenched and Tempered |
1/4 thru 4 | 150 | 159 | 237 | 7 |
| See Note 1,2 | 10 | ||||||
Hex Bolt Grade Identification and Mechanical Properties
| Identification Grade Mark |
Specification | Fastener Description |
Material | Nominal Size Range (in.) |
Mechanical Properties | ||
| Proof Load (psi) |
Yield Strength Min (psi) |
Tensile Strength Min (psi) |
|||||
 No Grade Mark |
SAE J429 Grade 1 |
Bolts, Screws, Studs |
Low or Medium Carbon Steel | 1/4 thru 1-1/2 | 33,000 | 36,000 | 60,000 |
| ASTM A307 Grades A&B |
Low Carbon Steel | 1/4 thru 4 | — | — | |||
| SAE J429 Grade 2 |
Low or Medium Carbon Steel | 1/4 thru 3/4 Over 3/4 to 1-1/2 | 55,000 33,000 |
57,000 36,000 |
74,000 60,000 |
||
No Grade Mark |
SAE J429 Grade 4 |
Studs | Medium Carbon Cold Drawn Steel | 1/4 thru 1-1/2 | — | 100,000 | 115,000 |
B5 |
ASTM A193 Grade B5 |
AISI 501 | 1/4 Thru 4 | — | 80,000 | 100,000 | |
B6 |
ASTM A193 Grade B6 |
AISI 410 | 85,000 | 110,000 | |||
B7 |
ASTM A193 Grade B7 |
AISI 4140, 4142, OR 4105 | 1/4 thru 2-1/2 Over 2-1/2 thru 4 Over 4 thru 7 |
— — — |
105,000 95,000 75,000 |
125,000 115,000 100,000 |
|
B16 |
ASTM A193 Grade B16 |
CrMoVa Alloy Steel | 105,000 95,000 85,000 |
125,000 115,000 100,000 |
|||
B8 |
ASTM A193 Grade B8 |
AISI 304 | 1/4 and larger | — | 30,000 | 75,000 | |
B8C |
ASTM A193 Grade B8C |
AISI 347 | |||||
B8M |
ASTM A193 Grade B8M |
AISI 316 | |||||
B8T |
ASTM A193 Grade B8T |
Bolts, Screws, Studs for High-Temperature Service |
AISI 321 | 1/4 and larger | — | 30,000 | 75,000 |
B8 |
ASTM A193 Grade B8 |
AISI 304 Strain Hardened |
1/4 thr 3/4 Over 3/4 thru 1 Over 1 thru 1-1/4 Over 1-1/4 thru 1-1/2 |
— — — — |
100,000 80,000 65,000 50,000 |
125,000 115,000 105,000 100,000 |
|
B8C |
ASTM A193 Grade B8C |
AISI 347 Strain Hardened |
|||||
B8M |
ASTM A193 Grade B8M |
AISI 316 Strain Hardened |
95,000 80,000 65,000 50,000 |
110,000 100,000 95,000 90,000 |
|||
B8T |
ASTM A193 Grade B8T |
AISI 321 Strain Hardened |
100,000 80,000 65,000 50,000 |
125,000 115,000 105,000 100,000 |
|||
L7 |
ASTM A320 Grade L7 |
Bolts, Screws, Studs for Low-Temperature Service |
AISI 4140, 4142 or 4145 |
1/4 thru 2-1/2 | — | 105,000 | 125,000 |
L7A |
ASTM A320 Grade L7A |
AISI 4037 | |||||
L7B |
ASTM A320 Grade L7B |
AISI 4137 | |||||
L7C |
ASTM A320 Grade LC7 |
AISI 8740 | |||||
L43 |
ASTM A320 Grade L43 |
AISI 4340 | 1/4 thru 4 | — | 105,000 | 125,000 | |
B8 |
ASTM A320 Grade B8 |
Bolts, Screws, Studs for Low-Temperature Service |
AISI 304 | 1/4 and larger | — | 30,000 | 75,000 |
B8C |
ASTM A320 Grade B8C |
AISI 347 | |||||
B8T |
ASTM A320 Grade B8T |
AISI 321 | |||||
B8F |
ASTM A320 Grade B8F |
AISI 303 or 303Se |
|||||
B8M |
ASTM A320 Grade B8M |
AISI 316 | |||||
B8 |
ASTM A320 Grade B8 |
AISI 304 | 1/4 thru 3/4 Over 3/4 thru 1 Over 1 thru 1-1/4 Over 1-1/4 thru 1-1/2 |
— — — — |
100,000 80,000 65,00 50,00 |
100,000 80,000 65,00 50,00 |
|
B8C |
ASTM A320 Grade B8C |
AISI 347 | |||||
B8F |
ASTM A320 Grade B8F |
AISI 303 or 303Se |
|||||
B8M |
ASTM A320 Grade B8M |
AISI 316 | |||||
B8T |
ASTM A320 Grade B8T |
AISI 321 | |||||
 |
SAE J429 Grade 5 |
Bolts, Screws, Studs |
Medium Carbon Steel, Quenched and Tempered | 1/4 thru 1 Over 1 to 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
| ASTM A449 | 1/4 thru 1 Over 1 to 1-1/2 Over 1-1/2 thru 3 |
85,000 74,000 55,000 |
92,000 81,000 58,000 |
120,000 105,000 90,000 |
|||
 |
SAE J429 Grade 5.1 |
Sems | Low or Medium Carbon Steel, Quenched and Tempered | No. 6 thru 3/8 |
85,000 | — | 120,000 |
 |
SAE J429 Grade 5.2 |
Bolts, Screws, Studs |
Low Carbon Martensitic Steel, Quenched and Tempered | 1/4 thru 1 | 85,000 | 92,000 | 120,000 |
A325 |
ASTM A325 Type 1 |
High Strength Structural Bolts |
Medium Carbon Steel, Quenched and Tempered | 1/2 thru 1 1-1/8 thru 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
A325 |
ASTM A325 Type 2 |
Low Carbon Martensitic Steel, Quenched and Tempered | 1/2 thru 1 | 85,000 | 92,000 | 120,000 | |
A325 |
ASTM A325 Type 3 |
Atmospheric Corrosion Resisting Steel, Quenched and Tempered | 1/2 thru 1 1-1/8 thru 1-1/2 |
85,000 74,000 |
92,000 81,000 |
120,000 105,000 |
|
 BB |
ASTM A354 Grade BB |
Bolts, Studs |
Alloy Steel, Quenched and Tempered | 1/4 thru 2-1/2 2-3/4 thru 4 |
80,000 75,000 |
83,000 78,000 |
105,000 100,000 |
 BC |
ASTM A354 Grade BC |
105,000 95,000 |
109,000 99,000 |
125,000 115,000 |
|||
 |
SAE J429 Grade 7 |
Bolts, Screws, |
Medium Carbon Alloy Steel, Quenched and Tempered 4 | 1/4 thru 1-1/2 | 105,000 | 115,000 | 133,000 |
 |
SAE J429 Grade 8 |
Bolts, Screws, Studs |
Medium Carbon Alloy Steel, Quenched and Tempered | 1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 |
| ASTM A354 Grade BD |
Alloy Steel, Quenched and Tempered 4 | ||||||
No Grade Mark |
SAE J429 Grade 8.1 |
Studs | Medium Carbon Alloy or SAE 1041 Modified Elevated Temperature Drawn Steel | 1/4 thru 1-1/2 | 120,000 | 130,000 | 150,000 |
A490 |
ASTM A490 | High Strength Structural Bolts | Alloy Steel, Quenched and Tempered | 1/2 thru 1-1/2 | 120,000 | 130,000 | 150,000 min 170,000 max |
No Grade Mark |
ISO R898 Class 4.6 |
Bolts, Screws, Studs |
Medium Carbon Steel, Quenched and Tempered | All Sizes thru 1-1/2 |
33,000 | 36,000 | 60,000 |
No Grade Mark |
ISO R898 Class 5.8 |
55,000 | 57,000 | 74,000 | |||
| 8.8 or 88 |
ISO R898 Class 8.8 |
Alloy Steel, Quenched and Tempered | 85,000 | 92,000 | 120,000 | ||
| 10.9 or 109 |
ISO R898 Class 10.9 |
120,000 | 130,000 | 150,000 | |||
Flat Washer Dimensions (ASME B18.22.1)
| Bolt Size | A | B | C | Weight In Pounds Per 100 Pieces |
|---|---|---|---|---|
| Inside Diameter | Outside Diameter | Thickness | ||
| 3/8 | 7/16 | 1 | 0.083 | 2 |
| 1/2 | 9/16 | 1-3/8 | 0.109 | 4 |
| 5/8 | 11/16 | 1-3/4 | 0.134 | 8 |
| 3/4 | 13/16 | 2 | 0.148 | 11 |
| 7/8 | 15/16 | 2-1/4 | 0.165 | 15 |
| 1 | 1-1/16 | 2-1/2 | 0.165 | 19 |
| 1-1/8 | 1-1/4 | 2-3/4 | 0.165 | 22 |
| 1-1/4 | 1-3/8 | 3 | 0.165 | 26 |
| 1-3/8 | 1-1/2 | 3-1/4 | 0.180 | 33 |
| 1-1/2 | 1-5/8 | 3-1/2 | 0.180 | 38 |
| 1-5/8 | 1-3/4 | 3-3/4 | 0.180 | 43 |
| 1-3/4 | 1-7/8 | 4 | 0.180 | 50 |
| 1-7/8 | 2 | 4-1/4 | 0.180 | 57 |
| 2 | 2-1/8 | 4-1/2 | 0.180 | 63 |
| 2-1/4 | 2-3/8 | 4-3/4 | 0.220 | 83 |
| 2-1/2 | 2-5/8 | 5 | 0.238 | 96 |
| 2-3/4 | 2-7/8 | 5-1/4 | 0.259 | 110 |
| 3 | 3-1/8 | 5-1/2 | 0.284 | 130 |
Hex Nut Dimensions
| Size | Across Flats* | Height | ||||
|---|---|---|---|---|---|---|
| Hex Nut | Machine Screw Nut | Hex Nut | Jam Nut | Nylock Nut | Machine Screw Nut | |
| 0 | – | 5/32 | – | – | – | 3/64 |
| 1 | – | 5/32 | – | – | – | 3/64 |
| 2 | – | 3/16 | – | – | 9/64 | 1/16 |
| 3 | – | 3/16 | – | – | 9/64 | 1/16 |
| 4 | – | 1/4 | – | – | 9/64 | 3/32 |
| 6 | – | 5/16 | – | – | 11/64 | 7/64 |
| 8 | – | 11/32 | – | – | 15/64 | 1/8 |
| 10 | – | 3/8 | – | – | 15/64 | 1/8 |
| 12 | – | 7/16 | – | – | 5/16 | 5/32 |
| 1/4 | 7/16 | 7/16 | 7/32 | 5/32 | 5/16 | 3/16 |
| 5/16 | 1/2 | 9/16 | 17/64 | 3/16 | 11/32 | 7/32 |
| 3/8 | 9/16 | 5/8 | 21/64 | 7/32 | 29/64 | 1/4 |
| 7/16 | 11/16 | – | 3/8 | 1/4 | 29/64 | – |
| 1/2 | 3/4 | – | 7/16 | 5/16 | 19/32 | – |
| 9/16 | 7/8 | – | 31/64 | 5/16 | 41/64 | – |
| 5/8 | 15/16 | – | 35/64 | 3/8 | 3/4 | – |
| 3/4 | 1-1/8 | – | 41/64 | 27/64 | 7/8 | – |
| 7/8 | 1-5/16 | – | 3/4 | 31/64 | 63/64 | – |
| 1 | 1-1/2 | – | 55/64 | 35/64 | 1-3/64 | – |
| * This is also the size of wrench to use. | ||||||
Hex Cap Bolt Dimensions
|
Hex Bolt Dimensions
|
||||||||
|
Basic Product Diameter
|
Full-Size Body Diameter
|
Width Across Flats
|
Width Across Corners
|
Head Height
|
Thread Length
|
Thread Length
|
||
|
Max
|
Min
|
Max
|
Min
|
Up to 6in
|
Over 6 in
|
|||
|
1/4
|
.26
|
.237
|
7/16
|
.505
|
0.484
|
11/64
|
0.75
|
1.00
|
|
5/16
|
.324
|
.298
|
1/2
|
.577
|
0.552
|
7/32
|
0.88
|
1.13
|
|
3/8
|
.388
|
.360
|
9/16
|
.650
|
0.62
|
1/4
|
1.00
|
1.25
|
|
7/16
|
.452
|
.421
|
5/8
|
.722
|
0.687
|
19/64
|
1.13
|
1.38
|
|
1/2
|
.515
|
.482
|
3/4
|
.866
|
0.826
|
11/32
|
1.25
|
1.50
|
|
5/8
|
.642
|
.605
|
15/16
|
1.083
|
1.033
|
27/64
|
1.50
|
1.75
|
|
3/4
|
.768
|
.729
|
1-1/8
|
1.299
|
1.24
|
1/2
|
1.75
|
2.00
|
|
7/8
|
.895
|
.852
|
1-5/16
|
1.516
|
1.447
|
37/64
|
2.00
|
2.25
|
|
1
|
1.022
|
.976
|
1-1/2
|
1.732
|
1.653
|
43/64
|
2.25
|
2.50
|
|
1-1/8
|
1.149
|
1.098
|
1-11/16
|
1.949
|
1.859
|
3/4
|
2.50
|
2.75
|
|
1-1/4
|
1.277
|
1.223
|
1-7/8
|
2.165
|
2.066
|
27/32
|
2.75
|
3.00
|
|
1-3/8
|
1.404
|
1.345
|
2-1/16
|
2.382
|
2.273
|
29/32
|
3.00
|
3.25
|
|
1-1/2
|
1.531
|
1.47
|
2-1/4
|
2.598
|
2.48
|
1
|
3.25
|
3.50
|
|
1-3/4
|
1.785
|
1.716
|
2-5/8
|
3.031
|
2.893
|
1-5/32
|
3.75
|
4.00
|
|
2
|
2.039
|
1.964
|
3
|
3.464
|
3.306
|
1-11/32
|
4.25
|
4.50
|
|
2-1/4
|
2.305
|
2.214
|
3-3/8
|
3.897
|
3.719
|
1-1/2
|
4.75
|
5.00
|
|
2-1/2
|
2.559
|
2.461
|
3-3/4
|
4.33
|
4.133
|
1-21/32
|
5.25
|
5.5
|
|
2-3/4
|
2.827
|
2.711
|
4-1/8
|
4.763
|
4.546
|
1-13/16
|
5.75
|
6.00
|
|
3
|
3.081
|
2.961
|
4-1/2
|
5.196
|
4.959
|
2
|
6.25
|
6.50
|
|
3-1/4
|
3.335
|
3.21
|
4-7/8
|
5.629
|
5.372
|
2-3/16
|
6.75
|
7.00
|
|
3-1/2
|
3.589
|
3.461
|
5-1/4
|
6.062
|
5.786
|
2-5/16
|
7.25
|
7.50
|
|
3-3/4
|
3.858
|
3.726
|
5-5/8
|
6.495
|
6.198
|
2-1/2
|
7.75
|
8.00
|
|
4
|
4.111
|
3.975
|
6
|
6.928
|
6.612
|
2-11/16
|
8.25
|
8.50
|
Metric Thread – Tap Drill / Clearance Drill
| Metric Tap Drill Chart | ||||||
| Tap size | Major Dia (mm) |
Threads per |
Tap Drill (mm) |
Tap Drill (inch) |
Clearance (mm) |
Clearance (inch) |
| M1.6×0.35 | 1.6 | 0.35 | 1.25 | #55 | 1.8 | #49 |
| M2x0.4 | 2.0 | 0.40 | 1.60 | #52 | 2.4 | #41 |
| M2.5×0.45 | 2.5 | 0.45 | 2.05 | #46 | 2.9 | #32 |
| M3x.05 | 3.0 | 0.50 | 2.50 | #39 | 3.4 | #29 |
| M3.5×0.6 | 3.5 | 0.60 | 2.90 | #32 | 3.9 | #23 |
| M4x0.7 | 4.0 | 0.70 | 3.30 | #30 | 4.5 | #16 |
| M5x0.8 | 5.0 | 0.80 | 4.20 | #19 | 5.5 | 7/32 |
| M6x1 | 6.0 | 1.00 | 5.0 | #8 | 6.6 | G |
| M8x1.25 | 8.0 | 1.25 | 6.8 | H | 9.0 | T |
| M8x1 | 8.0 | 1.00 | 7.0 | J | 9.0 | T |
| M10x1.5 | 10.0 | 1.50 | 8.5> | R | 12.0 | 31/64 |
| M10x1.25 | 10.0 | 1.25 | 8.8 | 11/32 | 12.0 | 31/64 |
| M12x1.75 | 12.0 | 1.75 | 10.2 | 13/32 | 14.0 | 35/64 |
| M12x1.25 | 12.0 | 1.25 | 10.8 | 27/64 | 14.0 | 35/64 |
| M14x2 | 14.0 | 2.00 | 12.0 | 15/32 | 16.0 | 5/8 |
| M14x1.5 | 14.0 | 1.5 | 12.5 | 1/2 | 16.0 | 5/8 |
| M16x2 | 16.0 | 2.00 | 14.0 | 35/64 | 18.0 | 45/64 |
| M16x1.5 | 16.0 | 1.50 | 14.5 | 37/64 | 18.0 | 45/64 |
| M18x2.5 | 18.0 | 2.50 | 15.5 | 39/64 | 20.0 | 51/64 |
| M18x1.5 | 18.0 | 1.50 | 16.5 | 21/32 | 20.0 | 51/64 |
| M20x2.5 | 20.0 | 2.50 | 17.5 | 11/16 | 22.0 | 7/8 |
| M20x1.5 | 20.0 | 1.50 | 18.5 | 47/64 | 22.0 | 7/8 |
| M22x2.5 | 22.0 | 2.50 | 19.5 | 49/64 | 25.0 | 1 |
| M22x1.5 | 22.0 | 1.50 | 20.5 | 13/16 | 25.0 | 1 |
| M24x3 | 24.0 | 3.00 | 21.0 | 53/64 | 27.0 | 1-5/64 |
| M24x2 | 24.0 | 2.00 | 22.0 | 7/8 | 27.0 | 1-5/64 |
| M27x3 | 27.0 | 3.00 | 24.0 | 15/16 | 30.0 | 1-3/16 |
| M27x2 | 27.0 | 2.0 | 25.0 | 1 | 30.0 | 1-3/16 |
Standard UNC Tap Drill Sizes
Standard UNF Tap Drill Sizes
Standard NPT Tap Drill Sizes
Unified Screw Threads – Fine (UNF)
| Size | Major Dia | Threads Per Inch | Pitch Dia | Minor Dia External | Minor Dia Internal | Minor Dia Area | Tensile Stress Area |
| # | inch | tpi | inch | inch | inch | sq. inch | sq. inch |
| #0 | 0.06 | 80 | 0.0519 | 0.0451 | 0.0465 | 0.00151 | 0.0018 |
| #1 | 0.073 | 72 | 0.064 | 0.0565 | 0.058 | 0.00237 | 0.00278 |
| #2 | 0.086 | 64 | 0.0759 | 0.0674 | 0.0691 | 0.00339 | 0.00394 |
| #3 | 0.099 | 56 | 0.0874 | 0.0778 | 0.0797 | 0.00451 | 0.00523 |
| #4 | 0.112 | 48 | 0.0985 | 0.0871 | 0.0894 | 0.00566 | 0.00661 |
| #5 | 0.125 | 44 | 0.1102 | 0.0979 | 0.1004 | 0.00716 | 0.0083 |
| #6 | 0.138 | 40 | 0.1218 | 0.1082 | 0.1109 | 0.00874 | 0.01015 |
| #8 | 0.164 | 36 | 0.146 | 0.1309 | 0.1339 | 0.01285 | 0.01474 |
| #10 | 0.19 | 32 | 0.1697 | 0.1528 | 0.1562 | 0.0175 | 0.02 |
| #12 | 0.216 | 28 | 0.1928 | 0.1734 | 0.1773 | 0.0226 | 0.0258 |
| 1/4 | 0.25 | 28 | 0.2268 | 0.2074 | 0.2113 | 0.0326 | 0.0364 |
| 5/16 | 0.3125 | 24 | 0.2854 | 0.2629 | 0.2674 | 0.0524 | 0.058 |
| 3/8 | 0.375 | 24 | 0.3479 | 0.3254 | 0.3299 | 0.0809 | 0.0878 |
| 7/16 | 0.4375 | 20 | 0.405 | 0.378 | 0.3834 | 0.109 | 0.1187 |
| 1/2 | 0.5 | 20 | 0.4675 | 0.4405 | 0.4459 | 0.1486 | 0.1599 |
| 9/16 | 0.5625 | 18 | 0.5264 | 0.4964 | 0.5024 | 0.189 | 0.203 |
| 5/8 | 0.625 | 18 | 0.5889 | 0.5589 | 0.5649 | 0.24 | 0.256 |
| 3/4 | 0.75 | 16 | 0.7094 | 0.6763 | 0.6823 | 0.351 | 0.373 |
| 7/8 | 0.875 | 14 | 0.8286 | 0.79 | 0.7977 | 0.48 | 0.509 |
| 1 | 1 | 12 | 0.9459 | 0.9001 | 0.9098 | 0.625 | 0.663 |
| 1-1/8 | 1.125 | 12 | 1.0709 | 1.0258 | 1.0348 | 0.812 | 0.856 |
| 1¼ | 1.25 | 12 | 1.1959 | 1.1508 | 1.1598 | 1.024 | 1.073 |
| 1-3/8 | 1.375 | 12 | 1.3209 | 1.2758 | 1.2848 | 1.26 | 1.315 |
| 1½ | 1.5 | 12 | 1.4459 | 1.4008 | 1.4098 | 1.521 | 1.581 |
Unified Screw Threads – Course (UNC)
| Size | Major Dia | Threads Per Inch | Pitch Dia | Minor Dia External | Minor Dia Internal | Minor Dia Area | Tensile Stress Area |
| # | inch | tpi | inch | inch | inch | sq. inch | sq. inch |
| #1 | 0.073 | 64 | 0.0629 | 0.0544 | 0.0561 | 0.00218 | 0.00263 |
| #2 | 0.086 | 56 | 0.0744 | 0.0648 | 0.0667 | 0.0031 | 0.0037 |
| #3 | 0.099 | 48 | 0.0855 | 0.0741 | 0.0764 | 0.00406 | 0.00487 |
| #4 | 0.112 | 40 | 0.0958 | 0.0822 | 0.0849 | 0.00496 | 0.00604 |
| #5 | 0.125 | 40 | 0.1088 | 0.0952 | 0.0979 | 0.00672 | 0.00796 |
| #6 | 0.138 | 32 | 0.1177 | 0.1008 | 0.1042 | 0.00745 | 0.00909 |
| #8 | 0.164 | 32 | 0.1437 | 0.1268 | 0.1302 | 0.01196 | 0.014 |
| #10 | 0.19 | 24 | 0.1629 | 0.1404 | 0.1449 | 0.0145 | 0.0175 |
| #12 | 0.216 | 24 | 0.1889 | 0.1664 | 0.1709 | 0.0206 | 0.0242 |
| ¼ | 0.25 | 20 | 0.2175 | 0.1905 | 0.1959 | 0.0269 | 0.0318 |
| 5/16 | 0.3125 | 18 | 0.2764 | 0.2464 | 0.2524 | 0.0454 | 0.0524 |
| 3/8 | 0.375 | 16 | 0.3344 | 0.3005 | 0.3073 | 0.0678 | 0.0775 |
| 7/16 | 0.4375 | 14 | 0.3911 | 0.3525 | 0.3602 | 0.0933 | 0.1063 |
| ½ | 0.5 | 13 | 0.45 | 0.4084 | 0.4167 | 0.1257 | 0.1419 |
| 9/16 | 0.5625 | 12 | 0.5084 | 0.4633 | 0.4723 | 0.162 | 0.182 |
| 5/8 | 0.625 | 11 | 0.566 | 0.5168 | 0.5266 | 0.202 | 0.226 |
| ¾ | 0.75 | 10 | 0.685 | 0.6309 | 0.6417 | 0.302 | 0.334 |
| 7/8 | 0.875 | 9 | 0.8028 | 0.7427 | 0.7547 | 0.419 | 0.462 |
| 1 | 1 | 8 | 0.9188 | 0.8512 | 0.8647 | 0.551 | 0.606 |
| 1-1/8 | 1.125 | 7 | 1.0322 | 0.9549 | 0.9704 | 0.693 | 0.763 |
| 1¼ | 1.25 | 7 | 1.1572 | 1.0799 | 1.0954 | 0.89 | 0.969 |
| 1-3/8 | 1.375 | 6 | 1.2667 | 1.1766 | 1.1946 | 1.054 | 1.155 |
| 1½ | 1.5 | 6 | 1.3917 | 1.3016 | 1.3196 | 1.294 | 1.405 |
| 1¾ | 1.75 | 5 | 1.6201 | 1.5119 | 1.5335 | 1.74 | 1.9 |
| 2 | 2 | 4.5 | 1.8557 | 1.7353 | 1.7594 | 2.3 | 2.5 |
| 2¼ | 2.25 | 4.5 | 2.1057 | 1.9853 | 2.0094 | 3.02 | 3.25 |
| 2½ | 2.5 | 4 | 2.3376 | 2.2023 | 2.2294 | 3.72 | 4 |
| 2¾ | 2.75 | 4 | 2.5876 | 2.4523 | 2.4794 | 4.62 | 4.93 |
| 3 | 3 | 4 | 2.8376 | 2.7023 | 2.7294 | 5.62 | 5.97 |
| 3¼ | 3.25 | 4 | 3.0876 | 2.9523 | 2.9794 | 6.72 | 7.1 |
| 3½ | 3.5 | 4 | 3.3376 | 3.2023 | 3.2294 | 7.92 | 8.33 |
| 3¾ | 3.75 | 4 | 3.5876 | 3.4523 | 3.4794 | 9.21 | 9.66 |
| 4 | 4 | 4 | 3.8376 | 3.7023 | 3.7294 | 10.61 | 11.08 |