A cap screw is a screw that has a thick wide head and a flat bottom toward the thread facing site. The hex head cap screw is the most common cap screw and is also the most common fastener in construction and machine assembly.
Our cap screws can be customized to your application and industry. Please review all of our standard cap screw charts below and download the size charts.
Basic Product Diameter | Threads per Inch | E | F | G | H | S | ||||||||||||
Body or Shoulder Diameter |
Width Across Flats |
Hex Lag Screws |
Shoulder Length | |||||||||||||||
Width Across Corners |
Head Height |
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Max. | Min. | Basic | Max. | Min. | Max. | Min. | Basic | Max. | Min. | Min. | ||||||||
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10 9 |
0.260 0.324 |
0.237 0.298 |
7/16 1/2 |
0.438 0.500 |
0.425 0.484 |
0.505 0.577 |
0.484 0.552 |
11/64 7/32 |
0.188 0.235 |
0.150 0.195 |
0.094 0.125 |
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7 7 6 |
0.388 0.452 0.515 |
0.360 0.421 0.482 |
9/16 5/8 3/4 |
0.562 0.625 0.750 |
0.544 0.603 0.725 |
0.650 0.722 0.866 |
0.620 0.687 0.826 |
1/4 19/64 11/32 |
0.268 0.316 0.364 |
0.226 0.272 0.302 |
0.125 0.156 0.156 |
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5 4-1/2 |
0.642 0.768 |
0.605 0.729 |
15/16 1-1/8 |
0.938 1.125 |
0.906 1.088 |
1.083 1.299 |
1.033 1.240 |
27/64 1/2 |
0.444 0.524 |
0.378 0.455 |
0.312 0.375 |
Basic Bolt Diameter |
E | A | H | 0 | P | |||||||||||||
Body Diameter |
Head Diameter |
Head Height |
Square Width |
Square Depth |
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Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | |||||||||
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0.199 0.260 0.324 0.388 |
0.182 0.237 0.298 0.360 |
0.469 0.594 0.719 0.844 |
0.438 0.563 0.688 0.782 |
0.114 0.145 0.176 0.208 |
0.094 0.125 0.156 0.188 |
0.199 0.260 0.324 0.388 |
0.185 0.245 0.307 0.368 |
0.125 0.156 0.187 0.219 |
0.094 0.125 0.156 0.188 |
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0.452 0.515 0.642 0.768 |
0.421 0.483 0.605 0.729 |
0.969 1.094 1.344 1.594 |
0.907 1.032 1.219 1.469 |
0.239 0.270 0.344 0.406 |
0.219 0.250 0.313 0.375 |
0.452 0.515 0.642 0.768 |
0.431 0.492 0.616 0.741 |
0.250 0.281 0.344 0.406 |
0.219 0.250 0.313 0.375 |
Size | A | B | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Thread Length | Collar Length | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Nominal Size or Basic Bolt Diameter |
EBody Diameter |
A | HHead Height |
0 | P | |||||||||||||
Head Diameter | Square Width |
Square Depth |
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Max. Edge Sharp |
Min. Edge Sharp |
Min. Edge Flat |
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Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | |||||||||||
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0.260 0.324 0.388 |
0.237 0.298 0.360 |
1.008 1.227 1.352 |
0.969 1.188 1.312 |
0.938 1.157 1.272 |
0.098 0.114 0.145 |
0.087 0.094 0.125 |
0.280 0.342 0.405 |
0.245 0.307 0.368 |
0.219 0.250 0.250 | 0.188 0.219 0.219 |
Nominal Or Basic |
E | F | G | H | ||||||||||||||
Body | Diameter | Width Across Flats | Width Across Corners | Head Height |
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Product Diam. | Max. | Min. | Basic | Max. | Min. | Max. | Min. | Basic | Max. | Min. | ||||||||
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0.2500 0.3125 0.3750 0.4375 |
0.2450 0.3065 0.3690 0.4305 |
7/16 1/2 9/16 5/8 |
0.438 0.500 0.562 0.625 |
0.428 0.489 0.551 0.612 |
0.505 0.577 0.650 0.722 |
0.488 0.557 0.628 0.698 |
5/32 13/64 15/64 9/32 |
0.163 0.211 0.243 0.291 |
0.150 0.195 0.226 0.272 |
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0.5000 0.5625 0.6250 0.7500 |
0.4930 0.5545 0.6170 0.7410 |
3/4 13/16 15/16 1-1/8 |
0.750 0.812 0.938 1.125 |
0.736 0.798 0.922 1.100 |
0.866 0.938 1.083 1.299 |
0.840 0.910 1.051 1.254 |
5/16 23/64 25/64 15/32 |
0.323 0.371 0.403 0.483 |
0.302 0.348 0.378 0.455 |
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0.8750 1.0000 1.1250 1.2500 |
0.8660 0.9900 1.1140 1.2390 |
1-5116 1-1/2 1-11/16 1-7/8 |
1.312 1.500 1.688 1.875 |
1.285 1.469 1.631 1.812 |
1.516 1.732 1.949 2.165 |
1.465 1.675 1.859 2.066 |
35/64 39/64 11/16 25/32 |
0.563 0.627 0.718 0.813 |
0.531 0.591 0.658 0.749 |
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1.3750 1.5000 |
1.3630 1.4880 |
2-1/6 2-1/4 |
2.062 2.250 |
1.994 2.175 |
2.382 2.598 |
2.273 2.480 |
27/32 15/16 |
0.878 0.974 |
0.810 0.902 |
D | A | L | S | B | ||||
Nominal Diameter of Bolt |
Diameter of Head | Feed Thickness | Depth of Square and Head | Width of Square | ||||
Max. | Min. Sharp |
Abs. Min. With Flat | Max. | Max. | Min. | Max. | Min. (Basic) |
|
3/8 7/16 |
0.708 0.826 |
0.671 0.781 |
0.656 0.766 |
0.031 0.036 |
0.312 0.364 |
0.281 0.328 |
0.387 0.450 |
0.375 0.438 |
1/2 5/8 3/4 |
0.945 1.147 1.303 |
0.890 1.094 1.250 |
0.875 1.063 1.219 |
0.042 0.050 0.050 |
0.417 0.506 0.541 |
0.375 0.456 0.491 |
0.515 0.640 0.765 |
0.500 0.625 0.750 |
Table 1 Dimensions of Slotted Flat Countersunk Head Cap Screws
Nominal Size orBasic Screw Diameter |
F | A | H | J | T | R | C | B | |||||||||||||
Body Diameter | Head Diameter | Head Height | Slot Width | Slot Depth | Fillet Radius | Protrusion Above Gaging Diameter |
Gaging Dia. | ||||||||||||||
Max, EdgeSharp | Min, Edge Rounded or Flat |
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Max | Min | Ref | Max | Min | Max | Min | Max | Max | Min | ||||||||||||
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0.2500 0.3125 0.3750 0.4375 |
0.2450 0.3070 0.3690 0.4310 |
0.500 0.625 0.750 0.812 |
0.452 0.567 0.682 0.736 |
0.140 0.177 0.210 0.210 |
0.075 0.084 0.094 0.094 |
0.064 0.072 0.081 0.081 |
.0.68 0.086 0.103 0.103 |
0.045 0.057 0.068 0.068 |
0.100 0.125 0.150 0.175 |
0.046 0.053 0.060 0.065 |
0.030 0.035 0.040 0.044 |
0.424 0.538 0.651 0.703 |
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0.5000 0.5625 0.6250 |
0.4930 0.5550 0.6170 |
0.875 1.000 1.125 |
0.791 0.906 1.020 |
0.210 0.244 0.281 |
0.106 0.118 0.133 |
0.091 0.102 0.116 |
0.103 0.120 0.137 |
0.068 0.080 0.091 |
0.200 0.225 0.250 |
0.071 0.078 0.085 |
0.049 0.054 0.058 |
0.756 0.869 0.982 |
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0.7500 0.8750 1.0000 |
0.7420 0.8660 0.9900 |
1.375 1.625 1.875 |
1.251 1.480 1.711 |
0.352 0.423 0.494 |
0.149 0.167 0.188 |
0.131 0.147 0.166 |
0.171 0.206 0.240 |
0.115 0.138 0.162 |
0.300 0.350 0.400 |
0.099 0.113 0.127 |
0.068 0.077 0.087 |
1.208 1.435 1.661 |
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1.1250 1.2500 1.3750 1.5000 |
1.1140 1.2390 1.3630 1.4880 |
2.062 2.312 2.562 2.812 |
1.880 2.110 2.340 2.570 |
0.529 0.600 0.665 0.742 |
0.196 0.211 0.226 0.258 |
0.178 0.193 0.208 0.240 |
0.257 0.291 0.326 0.360 |
0.173 0.197 0.220 0.244 |
0.450 0.500 0.550 0.600 |
0.141 0.155 0.169 0.183 |
0.096 0.105 0.115 0.124 |
1.826 2.052 2.279 2.505 |
Nominal Size Or Basic Major Dia. Of Thread |
E | F | G | B | U | H | LT | ||||||||||||||
Body Dia. | Width Across Flats | Width Across Corners |
Flange Dia. |
Flange Thickness | Head Height | Thread Lngth. | |||||||||||||||
L<6 In. | L>6 In. | ||||||||||||||||||||
Max. | Min. | Basic | Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | Basic | ||||||||||
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0.3750 0.5000 0.6250 0.7500 |
0.3690 0.4930 0.6170 0.7410 |
9/16 3/4 15/16 1-1/8 |
0.5625 0.7500 0.9375 1.1250 |
0.551 0.736 0.922 1.100 |
0.650 0.866 1.083 1.299 |
0.618 0.825 1.034 1.234 |
0.81 1.07 1.33 1.59 |
0.06 0.08 0.10 0.11 |
0.39 0.51 0.62 0.73 |
0.25 0.34 0.42 0.51 |
1.000 1.250 1.500 1.750 |
1.250 1.500 1.750 2.000 |
Nominal Or Basic Product Dia. |
E | F | G | H | R | LT | |||||||||||||||
Body Diameter | Width Across Flats | Width Across Corners |
Head Height | Radius of Fillet | Thread | Lngth. | |||||||||||||||
For Screw Lengths< 6 In. | For Screw Lengths > 6 In. | ||||||||||||||||||||
Max. | Min. | Basic | Max. | Min. | Max. | Min. | Basic | Max. | Min | Min. | Basic | Basic | |||||||||
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0.2500 0.3125 0.3750 0.4375 |
0.2450 0.3065 0.3690 0.4305 |
7/16 1/2 9/16 5/8 |
0.438 0.500 0.562 0.625 |
0.428 0.489 0.551 0.612 |
0.505 0.577 0.650 0.722 |
0.488 0.557 0.628 0.698 |
5/32 13/64 15/64 9/32 |
0.163 0.211 0.243 0.291 |
0.150 0.195 0.226 0.272 |
0.015 0.015 0.015 0.015 |
0.750 0.875 1.000 1.125 |
1.000 1.125 1.250 1.375 |
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0.5000 0.5625 0.6250 0.7500 |
0.4930 0.5545 0.6170 0.7410 |
3/4 13/16 15/16 1-1/8 |
0.750 0.812 0.938 1.125 |
0.736 0.798 0.922 1.100 |
0.866 0.938 1.083 1.299 |
0.840 0.910 1.051 1.254 |
5/16 23/64 25/64 15/32 |
0.323 0.371 0.403 0.483 |
0.302 0.348 0.378 0.455 |
0.015 0.020 0.020 0.020 |
1.250 1.375 1.500 1.750 |
1.500 1.625 1.750 2.000 |
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0.8750 1.0000 1.1250 1.2500 |
0.8660 0.9900 1.1140 1.2390 |
1-5/16 1-1/2 1-11/16 1-7/8 |
1.312 1.500 1.688 1.875 |
1.285 1.469 1.631 1.812 |
1.516 1.732 1.949 2.165 |
1.465 1.675 1.859 2.066 |
35/64 39/64 11/16 25/32 |
0.563 0.627 0.718 0.813 |
0.531 0.591 0.658 0.749 |
0.040 0.060 0.060 0.060 |
2.000 2.250 2.500 2.750 |
2.250 2.500 2.750 3.000 |
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1.3750 1.5000 |
1.3630 1.4880 |
2-1/6 2-1/4 |
2.062 2.250 |
1.994 2.175 |
2.382 2.598 |
2.273 2.480 |
27/32 15/16 |
0.878 0.974 |
0.810 0.902 |
0.060 0.060 |
3.000 3.250 |
3.250 3.500 |
Abstract of SAE J429 1985
Grade Designa tion |
Products | Nominal Size Dia., In. |
Full Size Bolts, Screws Studs, Sems |
Machine Test Specimens of Bolts, Screws and Studs |
Surface Hardness |
Core Hardness |
Grade Identification Marking L |
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Proof Load (Stress) psi |
Tensile Strength (Stress) Min.,psi |
Yield Strength (Stress) Min.,psi |
Tensile Strength (Stress) Min.,psi |
Elonga- tion Min., % |
Reduction of Area Min, % |
Rockwell 30N Max. |
Rockwell | |||||
Min. | Max. | |||||||||||
2 | Bolts, Screws, Studs |
1/4 thru 3/4 Over 3/4 to 1-1/2 |
55,000
33,000 |
74,000
60,000 |
57,000
36,000 |
74,000
60,000 |
18
18 |
35
35 |
—
— |
B80
B70 |
B100
B100 |
None |
5 | Bolts, Screws, Studs |
1/4 thru 3/4 Over 3/4 to 1-1/2 |
85,000
74,000 |
120,000
105,000 |
92,000
81,000 |
120,000
105,000 |
14
14 |
35
35 |
54
50 |
C25
C19 |
C34
C30 |
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8 | Bolts, Screws, Studs |
1/4 thru 1-1/2 | 120,000 | 150,000 | 130,000 | 150,000 | 12 | 35 | 58.6 | C33 | C39 |
Nominal Size or Basic Bolt Diameter |
E | A | H | O | P | |||||||||
Body Diameter |
Head Diameter |
Head Height |
Square Width |
Square Depth |
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Max. | Min. | Max. | Min | Max. | Min | Max. | Min | Max. | Min | |||||
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0.199 0.260 |
0.182 0.237 |
0.656 0.844 |
0.625 0.813 |
0.114 0.145 |
0.094 0.125 |
0.199 0.260 |
0.185 0.245 |
0.125 0.156 |
0.094 0.125 |
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0.324 0.388 |
0.298 0.360 |
1.031 1.219 |
1.000 1.188 |
0.176 0.208 |
0.156 0.188 |
0.324 0.388 |
0.307 0.368 |
0.187 0.219 |
0.156 0.188 |
Size | A | B | C | D | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Standard Length |
Machine Length |
Lag Thread Length |
Center Space |
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®Whiz-Lock is a registered trademark of the MacLean-Fogg Co.
Size | W | F |
Width Across Flats |
Flange Data |
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6 8 10 1/4 5/16 3/8 |
.187 .250 .312 .375 .500 .562 |
.260 .348 .433 .522 .696 .782 |