Hex Head Cap Screws Grades 5 and 8

Grade-5 & Grade-8 Hex Head Cap Screws ASME B18.2.1 1996
Nominal or Basic Product Diameter		E		F			G		H			J	L_T		Y
		Body Diameter		Width Across Flats			Width Across Corners		Head Height			Wren- ching Height	Thread Length		Transi- tion Thread Length
		Body Diameter		Width Across Flats			Width Across Corners		Head Height			Wren- ching Height	Screws Less or Equal to 6 inch	Screws More Than 6 inch	Transi- tion Thread Length
		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

Nominal Screw Size	Nominal Screw Length
Nominal Screw Size	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

Mechanical & Performance Data
for Grade-5 Hex Head Cap Screws

Description	A cap screw made from medium carbon steel and heat treated.
Applications and Advantages	Has greater tensile strength than a Grade-2. Yield-to-tensile ratio is the lowest of all heat treated steels.
Material	Medium carbon steel. Use of an alloy steel is acceptable.
Heat Treatment	Grade-5 cap screws shall be heat treated, oil or water quenched, at manufacturers option, and tempered at a minimum tempering temperature of 800°F.
Core Hardness	1/4 thru 1 inch diameter: Rockwell C25 - C34 1-1/8 thru 1-1/2 in. diameter: Rockwell C19 - C30
Surface Hardness	1/4 thru 1 inch diameter: Rockwell 30N54 maximum 1-1/8 thru 1-1/2 in. diameter: Rockwell 30N50 maximum
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
Yield Strength	1/4 thru 1 inch diameter: 92,000 psi 1-1/8 thru 1-1/2 inch diameter: 81,000 psi
Tensile Strength	1/4 thru 1 inch diameter: 120,000 psi 1-1/8 thru 1-1/2 inch diameter: 105,000 psi
Elongation*	14% 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 Grade-8 Hex Head Cap Screws

Description	A cap screw made from medium carbon alloy steel and heat treated.
Applications and Advantages	Has a greater tensile strength tha a Grade-5. designed for use in high stress applications where strength or safety is an issue. See specs below for more info on how the Grade-8 exceeds the strength of a Grade-5.
Material	Medium carbon alloy steel. Note: For diameters 1/4 thru 7/16 inch, it is permissible to use AISI 1541 steel.
Heat Treatment	Grade-8 cap screws shall be heat treated, oil quenched and tempered at a minimum of 800°F.
Surface Hardness	1/4 thru 1-1/2 inch diameter: Rochwell 30N58.6 maximum
Core Hardness	1/4 thru 1-1/2 inch diameter: Rockwell C33 - C39
Yield Strength*	1/4 thru 1-1/2 diameter: 130,000 psi minimum
Tensil Strength*	1/4 thru 1-1/2 diameter: 150,000 psi minimum
Elongation*	12% minimum
Reduction of Area	35% minimum
Proof Load	1/4 thru 1-1/2 inch diameter: 120,000 psi
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 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.

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