Hex Head Cap Screws
Grade-2 Hex Cap Screw Mechanicals & Performance DataStainless Hex Cap Screw Mechanicals & Performance Data
Grades 5 and 8 Hex Cap Screw Information
Hex Head Cap Screws Grade-2 & Stainless ASME B18.2.1 1996
| Nominal or Basic Product Diameter |
E | F | G | H | J | LT | Y | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Body Diameter | Width Across Flats | Width Across Corners |
Head Height | Wren- ching Height |
Thread Length | Transi- tion Thread Length |
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| Screws Less or Equal to 6 inch |
Screws More Than 6 inch |
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| Max | Min | Basic | Max | Min | Max | Min | Basic | Max | Min | Min | Ref | Ref | Max | ||
| 1/4 | .250 | .250 | .245 | 7/16 | .438 | .428 | .505 | .488 | 5/32 | .163 | .150 | .106 | .750 | 1.000 | .250 |
| 5/16 | .3125 | .3125 | .3065 | 1/2 | .500 | .489 | .577 | .557 | 16/64 | .211 | .0195 | .140 | .875 | 1.125 | .278 |
| 3/8 | .375 | .375 | .369 | 9/16 | .562 | .551 | .650 | .628 | 15/64 | .243 | .226 | .160 | 1.000 | 1.250 | .312 |
| 7/16 | .4375 | .4375 | .4305 | 5/8 | .625 | .612 | .722 | .698 | 9/32 | .291 | .272 | .195 | 1.125 | 1.375 | .357 |
| 1/2 | .500 | .500 | .493 | 3/4 | .750 | .736 | .866 | .840 | 5/16 | .323 | .302 | .215 | 1.250 | 1.500 | .385 |
| 9/16 | .5625 | .5625 | .5545 | 13/16 | .812 | .798 | .938 | .910 | 23/64 | .371 | .348 | .250 | 1.375 | 1.625 | .417 |
| 5/8 | .625 | .625 | .617 | 15/16 | .938 | .922 | 1.083 | 1.051 | 25/64 | .403 | .378 | .269 | 1.500 | 1.750 | .455 |
| 3/4 | .750 | .750 | .741 | 1-1/8 | 1.125 | 1.100 | 1.299 | 1.254 | 15/32 | .483 | .455 | .324 | 1.750 | 2.000 | .500 |
| 7/8 | .875 | .875 | .866 | 1-5/16 | 1.312 | 1.285 | 1.516 | 1.465 | 35/64 | .563 | .531 | .378 | 2.000 | 2.250 | .556 |
| 1 | 1.000 | 1.000 | .990 | 1-1/2 | 1.500 | 1.469 | 1.732 | 1.675 | 39/64 | .627 | .591 | .416 | 2.250 | 2.500 | .625 |
| 1-1/8 | 1.125 | 1.125 | 1.114 | 1-11/16 | 1.688 | 1.631 | 1.949 | 1.859 | 11/16 | .718 | .658 | .461 | 2.500 | 2.750 | .714 |
| 1-1/4 | 1.250 | 1.250 | 1.239 | 1-7/8 | 1.875 | 1.812 | 2.165 | 2.066 | 25/32 | .813 | .749 | .530 | 2.750 | 3.000 | .714 |
| 1-1/2 | 1.500 | 1.500 | 1.488 | 2-1/4 | 2.250 | 2.175 | 2.598 | 2.480 | 1-5/16 | .974 | .902 | .640 | 3.250 | 3.500 | .833 |
| Tolerance on Length | Nominal Screw Size | Nominal Screw Length | ||||
|---|---|---|---|---|---|---|
| Up to 1 in. Inclusive |
Over 1 in. to 2-1/2 in. Incl. |
Over 2-1/2 in. to 4 in. Incl. |
Over 4 in. to 6 in. Incl. |
Longer than 6 inch. |
||
| 1/4 to 3/8 | -.03 | -.04 | -.06 | -.10 | -.18 | |
| 7/16 to 1/2 | -.03 | -.06 | -.08 | -.10 | -.18 | |
| 9/16 to 3/4 | -.03 | -.08 | -.10 | -.10 | -.18 | |
| 7/8 to 1 | - | -.10 | -.14 | -.16 | -.20 | |
| 1-1/8 to 1-1/2 | - | -.12 | -.16 | -.18 | -.22 | |
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Mechanical & Performance Data for Grade-2 Hex Head Cap Screws |
| Description | A low or medium carbon steel, externally threaded mechanical device 1/4 inch or larger, with a trimmed hex head and a washer face on the bearing surface. |
|---|---|
| Applications and Advantages |
Economical for use in non-critical applications where the fastener is not subject to extreme temperatures or stress beyond the limits listed here. |
| Material | AISI 1006 - 1050 or equivalent steel |
| Hardness | 1/4 thru 3/4 in. diameter, 6 in. and shorter: Rockwell B80 - B100 1/4 thru 3/4 in. diameter, over 6 in. in length: Rockwell B70 - B100 7/8 thru 1-1/2 in. diameter: Rockwell B70 - B100 |
| Proof Load | 1/4 thru 3/4 in. diameter, 6 in. and shorter: 55,000 psi 1/4 thru 3/4 in. diameter, over 6 in. in length: 33,000 psi 7/8 thru 1-1/2 in. diameter: 33,000 psi |
| Tensile Strength |
1/4 thru 3/4 in. diameter, 6 in. and shorter: 74,000 psi minimum 1/4 thru 3/4 in. diameter, over 6 in. in length: 60,000 psi minimum 7/8 thru 1-1/2 in. diameter: 60,000 psi minimum |
| Yield Strength |
1/4 thru 3/4 in. diameter, 6 in. and shorter: 57,000 psi minimum 1/4 thru 3/4 in. diameter, over 6 in. in length: 36,000 psi minimum 7/8 thru 1-1/2 in. diameter: 36,000 psi minimum |
| Elongation* | 18% minimum |
| Reduction of Area |
35% minimum |
| Plating | See plating page for plating information |
| * These properties are tested only on machined specimens when the testing machine cannot provide for full testing of the parts. Note: Product standards require the manufacturer's head marking to appear on the top of all cap screws 1/4 inch diameter and larger. The X on the head image above represents a location that such marking may appear. Note: The length (L) of a cap screw is measured from the under-head bearing area to the extreme end of the screw. |
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Mechanical & Performance Data for 18-8 & 316 Stainless Hex Head Cap Screws |
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| Description | 18-8 & 316 stainless steel cap screws are both manufactured from austenitic alloys as described below. |
|---|---|
| Applications and Advantages |
18-8: Used in products that require general atmospheric corrosion resistance, such as chemical and food processing equipment. Some chemical environments may require special corrosion resistant material and precautions. 316: The molybdenum content gives this type of stainless even greater corrosion resistance than 18-8 as well as superior strength at high temperatures. |
| Material | 18-8: A cap screw made from one of the following austenitic alloys: 303, 303Se, XM&, all of which are characterized as having a chromium content of 17-19% and nickel content of 8-10%. 316: A cap screw made from 316 stainless steel, an austenitic alloy which differs from 18-8 by its molybdenum content (2-3%) and a higher nickel content (10-14%). |
| Heat Treatment | The austenitic alloys develop their strength through work hardening during the fastener manufacturing process, as seen from the hardness properties below. The only heat treatment normally available on austenitic stainless alloys is annealing, which is done at approximately 1900°F to a dead soft condition and is normally not thermally reversible. |
| Hardness | 1/4 thru 3/4 in. diameter, 6 in. and shorter: Rockwell B80 - B100 1/4 thru 3/4 in. diameter, over 6 in. in length: Rockwell B70 - B100 7/8 thru 1-1/2 in. diameter: Rockwell B70 - B100 |
| Proof Load | 1/4 thru 5/8 in. diameter: Rockwell B95 - C32 3/4 thru 1 in. diameter: Rockwell B80 - C32 |
| Tensile Strength |
1/4 thru 5/8 in. diameter, 2.25N in. and longer: 100,000 - 150,000 psi 3/4 (2.25N & longer)' & 7/8 thru 1 in, diameter (3N & longer): 85,000 - 140,000 psi |
| Yield Strength* |
1/4 thru 5/8 in. diameter, 2.25N and longer: 65,000 psi minimum 3/4 (2.25N & longer) & 7/8 thru 1 in. diameter (3N & longer): 45,000 psi minimum |
| Elongation in 4N* | 1.4 thru 5/8 in. diameter: 20% minimum 3/4 thru 1 in. diameter: 25% minimum |
| * These properties are tested only on machined specimens when the testing machine cannot provide for full testing of the parts. Note: Product standards require the manufacturer's head marking to appear on the top of all cap screws 1/4 inch diameter and larger. The X on the head images above represents a location that such marking may appear. Note: The length (L) of a cap screw is measured from the under-head bearing area to the extreme end of the screw. N = Nominal diameter of the screw in inches |
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Smith Fastener Company • 3613 East Florence Avenue, Bell, California, 90201 Phone: ( 323 ) 587-0382 • FAX: ( 323 ) 587-8712 • E-mail: sales@smithfast.com Copyright © 2009 by Smith Fastener Company |
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