Q: Is a bolt stronger because it is made of stainless steel?
A: No, stainless steel bolts are rated for corrosion resistance. Bolt strength is rated in PSI (pounds per square inch). A stainless steel bolt has the same PSI rating as a grade 5 bolt (125,000 PSI). A grade 8 bolt has a stronger rating with a PSI of 150,000.


Q: Is a hex cap screw (bolt) partially threaded or fully threaded?
A: The ISO standard for hex cap screw thread length is 2 times the diameter plus 1/2 inch. Fully threaded bolts are called "tap bolts". Tap bolts are not found on our website, you need to call us direct at 800-872-5557.


Q: What does ISO stand for?
A: ISO stands for International Organization for Standardization. A link to their website can be found here: ISO


Q: What is the difference between a hex head cap screw and a socket screw?
A: A socket screw is driven down with an "Allen Key". A hex head cap screw is driven down with a socket.


Q: Do you have a catalog?
A: No. We are concentrating on putting our products on the web through NutsandBolts.com as an alternative to a catalog.

Screw Thread Tables
Coarse Thread Table


Basic Dimensions for Coarse Thread Series Parts (UNC/UNRC)

(measured in inches)

Nominal Size

Major Diameter

Threads/inch

Basic Pitch Diameter

Minor Diameter

Lead Angle
at Basic Pitch Diameter

Height of Fundamental Triangle

Tensile Stress Area

 

 

 

 

 

(Degrees)

(Min)

 

(square inches)

#1

0.073

64

0.063

0.056

4

31

0.01353

0.003

#2

0.086

56

0.074

0.067

4

22

0.01547

0.004

#3

0.099

48

0.086

0.076

4

26

0.01804

0.005

#4

0.112

40

0.096

0.085

4

45

0.02165

0.006

#5

0.125

40

0.109

0.098

4

11

0.02165

0.008

#6

0.138

32

0.118

0.104

4

50

0.02706

0.009

#8

0.164

32

0.144

0.130

3

58

0.02706

0.014

#10

0.190

24

0.163

0.145

4

39

0.03608

0.018

#12

0.216

24

0.189

0.171

4

1

0.03608

0.024

1/4

0.250

20

0.218

0.196

4

11

0.04330

0.032

5/16

0.313

18

0.276

0.252

3

40

0.04811

0.052

3/8

0.375

16

0.334

0.307

3

24

0.05413

0.078

7/16

0.438

14

0.391

0.360

3

20

0.06186

0.106

1/2

0.500

13

0.450

0.417

3

7

0.06662

0.142

9/16

0.563

12

0.508

0.472

2

59

0.07217

0.182

5/8

0.625

11

0.566

0.527

2

56

0.07873

0.226

3/4

0.750

10

0.685

0.642

2

40

0.08660

0.334

7/8

0.875

9

0.803

0.755

2

31

0.09623

0.462

1

1.000

8

0.919

0.865

2

29

0.10825

0.606

1 1/8

1.125

7

1.032

0.941

2

31

0.12372

0.763

1 1/4

1.250

7

1.157

1.095

2

15

0.12372

0.969

1 3/8

1.375

6

1.267

1.195

2

24

0.14434

1.155

1 1/2

1.500

6

1.392

1.320

2

11

0.14434

1.405

1 3/4

1.750

5

1.620

1.534

2

15

0.17321

1.900

2

2.000

4 1/2

1.856

1.759

2

11

0.19245

2.500

2 1/4

2.250

4 1/2

2.106

2.009

1

55

0.19245

3.250

2 1/2

2.500

4

2.338

2.229

1

57

0.21651

4.000

2 3/4

2.750

4

2.588

2.479

1

46

0.21651

4.930

3

3.000

4

2.838

2.729

1

36

0.21651

5.970

3 1/4

3.250

4

3.088

2.979

1

29

0.21651

7.100

3 1/2

3.500

4

3.338

3.229

1

22

0.21651

8.330

3 3/4

3.750

4

3.588

3.479

1

16

0.21651

9.660

4

4.000

4

3.838

3.729

1

11

0.21651

11.080

(standards set by American Society of Mechanical Engineers)

 

Fine Thread Table


Basic Dimensions for Fine Thread Series Parts (UNF/UNRF)

(measured in inches)

Nominal Size

Major Diameter

Threads/inch

Basic Pitch Diameter

Minor Diameter

Lead Angle
at Basic Pitch Diameter

Height of Fundamental Triangle

Tensile Stress Area

 

 

 

 

 

(Degrees)

(Min)

 

(square inches)

#0

0.060

80

0.052

0.047

4

23

0.01083

0.002

#1

0.073

72

0.064

0.058

3

57

0.01203

0.003

#2

0.086

64

0.076

0.069

3

45

0.01353

0.004

#3

0.099

56

0.087

0.080

3

43

0.01547

0.005

#4

0.112

48

0.099

0.089

3

51

0.01804

0.007

#5

0.125

44

0.110

0.100

3

45

0.01968

0.008

#6

0.138

40

0.122

0.111

3

44

0.02165

0.010

#8

0.164

36

0.146

0.134

3

28

0.02406

0.015

#10

0.190

32

0.170

0.156

3

21

0.02706

0.020

#12

0.216

28

0.193

0.177

3

22

0.03093

0.026

1/4

0.250

28

0.227

0.211

2

52

0.03093

0.036

5/16

0.313

24

0.285

0.267

2

40

0.03608

0.058

3/8

0.375

24

0.348

0.330

2

11

0.03608

0.088

7/16

0.438

20

0.405

0.383

2

15

0.04330

0.119

1/2

0.500

20

0.468

0.446

1

57

0.04330

0.160

9/16

0.563

18

0.526

0.502

1

55

0.04811

0.203

5/8

0.625

18

0.589

0.565

1

43

0.04811

0.256

3/4

0.750

16

0.709

0.682

1

36

0.05413

0.373

7/8

0.875

14

0.829

0.798

1

34

0.06186

0.509

1

1.000

14

0.946

0.903

1

36

0.07217

0.663

1 1/8

1.125

12

1.071

1.035

1

25

0.07217

0.856

1 1/4

1.250

12

1.196

1.160

1

16

0.07217

1.073

1 3/8

1.375

12

1.321

1.285

1

9

0.07217

1.315

1 1/2

1.500

12

1.446

1.410

1

3

0.07217

1.581

(standards set by American Society of Mechanical Engineers)

Guide to Fastener Sizes


Understanding Standard Size Dimensions
The Size Dimension pertains to diameter of screws, bolts, & pins and inner diameter of nuts and washers. You may search for your product based on diameter by selecting a measurement on the Size dropdown. Other size measurements, such as screw, bolts, pin length, the outer diameters of nuts & washers, etc., appear on the search result itself.
A. Parts that Require Matching with a Mating Item
For example: Screws or bolts that drill through nuts, washers
Those parts that require matching with a mating item - screws or bolts with nuts or washers - have diameters that are denominated in actual inches or fractions thereof, followed by the number of threads per inch.
Screws and bolts that mate with a nut, as well as the nuts themselves, are denominated as such. Washers are not.
It is important to note that when matching a washer with a screw or a bolt, the diameter of the shaft of the screw or bolt should be matched to the inner diameter of the washer. For example, a ¾-16 bolt should be matched with a ¾ washer. The inner diameter of the ¾” washer will, in fact, be slightly larger than ¾” thereby enabling the washer to fit around the bolt. Consequently, when ordering a washer for a use other than matching it to a screw or a bolt, one should determine the actual inner iameter of the washer before placing an order.
Examples:
1. A fraction followed by a hyphen, followed by a number:
The fraction is the diameter of the shaft, in fraction of an inch. The number following the hyphen is the number of threads per inch, that is, the number of threads on the shaft itself, per inch of shaft length.
1/4-20: One quarter inch shaft diameter, 20 threads per inch
3/4-16: Three quarter inch shaft diameter, 16 threads per inch
2. For parts 1 inch or larger:
A number 1 or number larger than one, or number one or number larger than one followed by a fraction, then followed by a hyphen then a fraction or whole number:
The number 1 or number larger than one, or number one or number larger than one followed by a fraction, is the diameter of the shaft. The number following the hyphen is the number of threads per inch; that is, the number of threads on the shaft itself, per inch of shaft length. Same as for smaller parts.
1-12: One inch shaft diameter, 12 threads per inch
2-1/4-4-1/2: Two and one quarter inch shaft diameter, four and a half threads per inch
Note: The diameters of some smaller machine screws (though they may take a mating part), are denominated with the industry Numeric Size system described below. See section C below for clarification.
B. Parts that do not Require Matching with a Mating Item
Those parts that do not require matching with a mating item - screws or bolts that simply drill into or through a surface - are often denominated by industry Numeric Sizes preceded by a # sign. These do not show a number of threads-per-inch designation. These industry Numeric Sizes run from #0 through #15, with #0 the smallest and #15 the largest.
These Numeric Sizes are shaft diameters (and inner diameters of some washers) that were standardized years ago by the American Society of Mechanical Engineers (ASME), American Society of Testing & Materials (ASTM), and other standards bodies. These sizes were standardized based on sizes already commonly in use in the market.
1. Examples:
An industry Numeric Size, preceded by a # sign:
#6: A Number 6 size (sheet metal screws, Teks screws, drywall screws, particle board screws, wood screws, U-drive screws)
#8: A Number 8 size (sheet metal screws, Teks screws, drywall screws, particle board screws, wood screws, U-drive screws)
#14: A Number 14 size (sheet metal screws, Teks screws, wood screws)
2. Basic Major Diameters of industry Numeric Size-denominated screws:
(in inches)
#0: 0.0600 or 3/50 in
#1: 0.0730 or 73/1000 in
#2: 0.0860 or 43/500 in
#3: 0.0990 or 99/1000 in
#4: 0.1120 or 14/125 in
#5: 0.1250 or 1/8 in
#6: 0.1380 or 69/500 in
#7: 0.151 or 77/512
#8: 0.1640 or 41/250 in
#9: 0.1770 or 11/64 in
#10: 0.1900 or 19/100 in
#12: 0.2160 or 27/125 in
#14: 0.2500 or 1/4 in
#15: 0.3120 or 5/16 in
#16: 0.3750 or 3/8 in
Numeric Size denominations larger than #16 are uncommon.
Diameters are based on ASME Coarse Thread Series (UNC/UNRC) and ASME Fine Thread Series (UNF/UNRF)
C. Machine Screw Diameters denominated with the industry Numeric Size system
The diameters of smaller machine screws are denominated with the same Basic Major Diameters of industry Numeric Size-denominated screws noted in section B. 2. above, but with a number of threads per inch count as well. Here follows a list, in inches:
2-56: 0.0860 or 43/500 in diameter; 56 threads per inch
4-40: 0.1120 or 14/125 in diameter; 40 threads per inch
5-40: 0.1250 or 1/8 in diameter; 40 threads per inch
6-32: 0.1380 or 69/500 in diameter; 32 threads per inch
8-32: 0.1640 or 41/250 in diameter; 32 threads per inch
10-32: 0.1900 or 19/100 in diameter; 32 threads per inch
10-24: 0.1900 or 19/100 in diameter; 24 threads per inch
12-24: 0.2160 or 27/125 in diameter; 24 threads per inch

 

Guide to Fastener Materials


Note: Steel low-carbon is generally the default steel selection when no other steel grade is specified, or when no higher grade steel is required. Please check your application needs if you are not certain.
Mechanical Guidelines for Fasteners - Screws, Nuts, Bolts, Washers, Pins

Steel Grade

Material & Treatment

Proof Load Stress

Yield Strength

Tensile Strength

Core Hardness, Rockwell

Standards Authority

 

 

ksi (1000 lbs/sq inch) Min.

ksi (1000 lbs/sq inch) Min.

ksi (1000 lbs/sq inch) Min.

 

 

Low-carbon grade 2

Low/medium carbon steel, cold-forged

55

57

74

B70-B100

Society of Automotive Engineers

Grade A

Low/medium carbon steel

90-100

95-105

60

B69-B100

American Society for Testing & Materials

Grade B

Low/medium carbon steel

70-133

76-139

60-100

B69-B95

American Society for Testing & Materials

Grade 5

Medium carbon steel, quenched & tempered

74-85

81-82

105-120

C19-C34

Society of Automotive Engineers

Grade 8

Medium carbon alloy steel, quenched & tempered

120

130

150

C33-C39

Society of Automotive Engineers

Grade C

Medium carbon steel

144

154

N/A

B78-C38

American Society for Testing & Materials

2-H

Medium carbon steel

144

154

N/A

B78-C38

Society of Automotive Engineers

Strength guidelines may vary by part thickness, number of threads/inch, finish, and other design or production factors.

InStock Fasteners publishes this list to serve as a guideline to the materials we market. InStock Fasteners makes no warranty of any kind as to the certification of parts sold meeting these specifications.

Guide to Screw Points


Type A: Found on Sheet Metal (Tapping) Screws
http://www.instockfasteners.com/GRAPHICS/TypeA.gif
Type A tapping screws have coarse threads and gimlet points. They are used in thin metal, resinous plywood, and various composite boards.
Type AB: Found on Sheet Metal (Tapping) Screws
http://www.instockfasteners.com/GRAPHICS/TypeAB.gif
Type AB tapping screws have spaced threads and gimlet points. Like the Type A, they are used in thin metal, resinous plywood, and various composite boards. Type AB screws offer a wider range of applications over Type A screws.
Type B: Found on Sheet Metal (Tapping) Screws
http://www.instockfasteners.com/GRAPHICS/TypeB.gif
Type B tapping screws have spaced threads and a blunt point with incomplete entering threads. They are used in thin metal, nonferrous castings, resinous plywood, plastics, and various composite boards.
Type 25: Found on Thread Cutting Screws
http://www.instockfasteners.com/GRAPHICS/Type25.gif
Also known as Type BT, Type 25 screws have spaced, incomplete tapered threads with a blunt point and tapered entering edges, with one or more cutting edges and chip removal indentations. They are used in plastic, asbestos compositions, and other composites.
Type F: Found on Thread Cutting Screws
http://www.instockfasteners.com/GRAPHICS/TypeF.gif
Type F screws have machine screw threads with a blunt point and tapered entering edges, with one or more cutting edges and chip removal indentations. They are used in nonferrous castings, steel sheets, plastics, brass, cast iron, etc.
Type 23: Found on Thread Cutting Screws
http://www.instockfasteners.com/GRAPHICS/Type23.gif
Also known as Type T, Type 23 screws have machine screw threads with a blunt point and tapered entering edges, with one or more cutting edges and chip removal indentations. In this sense they are similar to Type F screws. The cutting edge on the point, however, is broader and deeper than that of the Type F. Type 23 screws are also used in nonferrous castings, steel sheets, plastics, brass, cast iron, etc.
Type 17: Found on Thread Cutting Screws
http://www.instockfasteners.com/GRAPHICS/Type17.gif
A thread cutting screw especially for wood, with a coarse tapping screw thread and a special long sharp point fluted to capture chips.


Teks screw (Self-Drilling Screw)

http://www.instockfasteners.com/GRAPHICS/Type2.gif

http://www.instockfasteners.com/GRAPHICS/Type3.gif

Type 2

Type 3

Teks screws, also known as self drilling screws, drill their own hole in thin sheet metal, heavier gauge metals and other materials, then form close mating threads in the hole. The Teks screw is ideal for automated assembly and reduces or eliminates the need for drill bits or taps. Once the hole is drilled, Teks screws (self drilling screws) tap the hole in the same way as thread forming or thread cutting screws do in a pre-drilled hole. They are also designed to eliminate paint build-up, weld flash, or foreign material that may occur in pre-drilled or pre-punched holes.
Type U-drive:
http://www.instockfasteners.com/GRAPHICS/TypeU.gif
U-Drive screws are round head metallic drive screws having multiple start threads of large helix angle, with a pivot. Featuring case-hardened threads, designed to be harder than the mating part. The Type U-Drive Screw is used when an attachment is not meant to be removed. It is driven into an undersized hole for great adherence, usually in metals or plastics. U-Drive Screws also have a round, unslotted head, again intended for a permanent fixture.

 

Fasteners' Inches to Metric Conversion Chart

 

 

Inches

Inches

Millimeters

Centimeters

Meters

 

Fractional

Decimal

 

 

 

 

1/64

0.0156

0.3969

0.03969

0.000397

 

1/32

0.0312

0.7925

0.07925

0.000793

 

3/64

0.0469

1.1906

0.11906

0.001191

1/16

1/16

0.0625

1.5875

0.15875

0.001588

 

5/64

0.0781

1.9844

0.19844

0.001984

 

3/32

0.0938

2.3813

0.23813

0.002381

 

7/64

0.1094

2.7781

0.27781

0.002778

1/8

1/8

0.1250

3.1750

0.3175

0.003175

 

9/64

0.1406

3.5719

0.35719

0.003572

 

5/32

0.1562

3.9675

0.39675

0.003968

 

11/64

0.1719

4.3656

0.43656

0.004366

3/16

3/16

0.1875

4.7625

0.47625

0.004763

 

13/64

0.2031

5.1594

0.51594

0.005159

 

7/32

0.2188

5.5563

0.55563

0.005556

 

15/64

0.2344

5.9531

0.59531

0.005953

1/4

1/4

0.2500

6.3500

0.635

0.00635

 

17/64

0.2656

6.7469

0.67469

0.006747

 

9/32

0.2812

7.1425

0.71425

0.007143

 

19/64

0.2969

7.5406

0.75406

0.007541

5/16

5/16

0.3125

7.9375

0.79375

0.007938

 

21/64

0.3281

8.3344

0.83344

0.008334

 

11/32

0.3438

8.7313

0.87313

0.008731

 

23/64

0.3594

9.1281

0.91281

0.009128

3/8

3/8

0.3750

9.5250

0.9525

0.009525

 

25/64

0.3906

9.9219

0.99219

0.009922

 

13/32

0.4062

10.3175

1.03175

0.010318

 

27/64

0.4219

10.7156

1.07156

0.010716

7/16

7/16

0.4375

11.1125

1.11125

0.011113

 

29/64

0.4531

11.5094

1.15094

0.011509

 

15/32

0.4688

11.9063

1.19063

0.011906

 

31/64

0.4844

12.3031

1.23031

0.012303

1/2

1/2

0.5000

12.7000

1.27

0.0127

 

33/64

0.5156

13.0969

1.30969

0.013097

 

17/32

0.5312

13.4925

1.34925

0.013493

 

35/64

0.5469

13.8906

1.38906

0.013891

9/16

9/16

0.5625

14.2875

1.42875

0.014288

 

37/64

0.5781

14.6844

1.46844

0.014684

 

19/32

0.5938

15.0813

1.50813

0.015081

 

39/64

0.6094

15.4781

1.54781

0.015478

5/8

5/8

0.6250

15.8750

1.5875

0.015875

 

41/64

0.6406

16.2719

1.62719

0.016272

 

21/32

0.6562

16.6675

1.66675

0.016668

 

43/64

0.6719

17.0656

1.70656

0.017066

11/16

11/16

0.6875

17.4625

1.74625

0.017463

 

45/64

0.7031

17.8594

1.78594

0.017859

 

23/32

0.7188

18.2563

1.82563

0.018256

 

47/64

0.7344

18.6531

1.86531

0.018653

3/4

3/4

0.7500

19.0500

1.905

0.01905

 

49/64

0.7656

19.4469

1.94469

0.019447

 

25/32

0.7812

19.8425

1.98425

0.019843

 

51/64

0.7969

20.2406

2.02406

0.020241

13/16

13/16

0.8125

20.6375

2.06375

0.020638

 

53/64

0.8281

21.0344

2.10344

0.021034

 

27/32

0.8438

21.4313

2.14313

0.021431

 

55/64

0.8594

21.8281

2.18281

0.021828

7/8

7/8

0.8750

22.2250

2.2225

0.022225

 

57/64

0.8906

22.6219

2.26219

0.022622

 

29/32

0.9062

23.0175

2.30175

0.023018

 

59/64

0.9219

23.4156

2.34156

0.023416

15/16

15/16

0.9375

23.8125

2.38125

0.023813

 

61/64

0.9531

24.2094

2.42094

0.024209

 

31/32

0.9688

24.6063

2.46063

0.024606

 

63/64

0.9844

25.0031

2.50031

0.025003

1 inch

1

1.0000

25.4000

2.54

0.0254

6 inches

6

6.0000

152.4000

15.24

0.1524

12 inches

12

12.0000

304.8000

30.48

0.3048

24 inches

24

24.0000

609.6000

60.96

0.6096

36 inches

36

36.0000

914.4000

91.44

0.9144

 

Fasteners' Metric to Inches Conversion Chart

 

Millimeters

Inches

Inches

Centimeters

Meters

 

Decimal

Fractional

 

 

0.3969

0.0156

1/64

0.04

0.0004

0.7925

0.0312

1/32

0.08

0.0008

1.0000

0.0394

 

0.10

0.0010

1.5875

0.0625

1/16

0.16

0.0016

2.0000

0.0788

 

0.20

0.0020

3.1750

0.1251

1/8

0.32

0.0032

3.0000

0.1182

 

0.30

0.0030

4.0000

0.1576

 

0.40

0.0040

5.0000

0.1970

 

0.50

0.0050

6.3500

0.2502

1/4

0.64

0.0064

7.0000

0.2758

 

0.70

0.0070

8.0000

0.3152

 

0.80

0.0080

9.0000

0.3546

 

0.90

0.0090

9.5250

0.3753

3/8

0.95

0.0095

10.0000

0.3940

 

1.00

0.0100

11.0000

0.4334

 

1.10

0.0110

12.0000

0.4728

 

1.20

0.0120

12.7000

0.5004

1/2

1.27

0.0127

13.0000

0.5122

 

1.30

0.0130

14.0000

0.5516

 

1.40

0.0140

15.0000

0.5910

 

1.50

0.0150

15.8750

0.6255

5/8

1.59

0.0159

16.0000

0.6304

 

1.60

0.0160

17.0000

0.6698

 

1.70

0.0170

18.0000

0.7092

 

1.80

0.0180

19.0500

0.7506

3/4

1.91

0.0191

20.0000

0.7880

 

2.00

0.0200

22.2250

0.8757

7/8

2.22

0.0222

25.4000

1.0000

1 inch

2.54

0.0254

30.0000

1.1820

 

3.00

0.0300

35.0000

1.3790

 

3.50

0.0350

40.0000

1.5760

 

4.00

0.0400

45.0000

1.7730

 

4.50

0.0450

50.0000

1.9700

 

5.00

0.0500

60.0000

2.3640

 

6.00

0.0600

70.0000

2.7580

 

7.00

0.0700

80.0000

3.1520

 

8.00

0.0800

90.0000

3.5460

 

9.00

0.0900

100.0000

3.9400

 

10.00

0.1000

110.0000

4.3340

 

11.00

0.1100

120.0000

4.7280

 

12.00

0.1200

130.0000

5.1220

 

13.00

0.1300

140.0000

5.5160

 

14.00

0.1400

150.0000

5.9100

 

15.00

0.1500

160.0000

6.3040

 

16.00

0.1600

170.0000

6.6980

 

17.00

0.1700

180.0000

7.0920

 

18.00

0.1800

190.0000

7.4860

 

19.00

0.1900

200.0000

7.8800

 

20.00

0.2000

220.0000

8.6680

 

22.00

0.2200

240.0000

9.4560

 

24.00

0.2400

260.0000

10.2440

 

26.00

0.2600

280.0000

11.0320

 

28.00

0.2800

300.0000

11.8200

 

30.00

0.3000

320.0000

12.6080

 

32.00

0.3200

340.0000

13.3960

 

34.00

0.3400

360.0000

14.1840

 

36.00

0.3600

400.0000

15.7600

 

40.00

0.4000

440.0000

17.3360

 

44.00

0.4400

480.0000

18.9120

 

48.00

0.4800

500.0000

19.7000

 

50.00

0.5000

750.0000

29.5500

 

75.00

0.7500

1000.0000

39.4000

 

100.00

1.0000