Socket Products

Socket products feature a hexagonal recess that requires a hex key (Allen wrench) for installation, making them ideal for tight spaces while providing a clean, low-profile look. These high-strength fasteners come in two main materials: heat-treated alloy steel (available in black oxide or zinc plating) and cold-worked stainless steel (in both 18-8 and 316 grades). All our socket products meet ASTM and ANSI standards with full traceability, and they’re commonly used in industrial machinery assembly and maintenance where superior strength and vibration resistance are essential.

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Socket Types

Socket Head Cap Screws

Socket Head Cap screws are commonly used in industrial and manufacturing applications that require high strength and durability, like machine parts and removable panels. They are ideal for assembly work that requires close tolerances and have a greater tensile strength than Grade 5 or Grade 8 Hex head cap screws. This type of screw is often counterbored.

US-Inch standard dimensional specifications meet ASME B18.3 specifications. The mechanical specifications for alloy follow ASTM F574, and stainless follows ASTM F837.

Metric specifications match ISO 4762 standards. Metric Socket Head Cap Screws are available in alloy Grade 12.9 and stainless 18-8 (A2) or 316 stainless (A4).

ASTM F574 (Alloy)

Hardness	0 thru 1/2” diameter: Rockwell C39 minimum 5/8” diameter and larger: Rockwell C37 minimum
Yield Strength	0 thru 1/2” diameter: 162,000 psi 5/8” diameter and larger: 153,000 psi
Tensile Strength	0 thru 1/2” diameter: 180,000 psi 5/8” diameter and larger: 170,000 psi
Elongation	10% minimum
Reduction of Area	33% minimum

ASTM F837 (Stainless)

Type	Nominal Size	Condition	Tensile Strength Min. PSI	Hardness Min. HRA	Grade Marking
304 (18-8)	0 to 3/4"	CW	80,000	50	F837B
304 (18-8)	0 to 3/4"	CW1	102,000	59	F837C
316	0 to 3/4"	CW	80,000	50	F837E
316	0 to 3/4"	CW1	102,000	59	F837F

Socket Head Cap Screws ASME B18.3

	D		A		H		J	T	Lt
Size	Body Diameter		Head Diameter		Head Height		Hex Size	Key Engagement	Thread Length
Size	Max	Min	Max	Min	Max	Min	Hex Size	Min	Thread Length
0	0.0600	0.0568	0.096	0.091	0.060	0.057	0.050	0.025	0.500
1	0.0730	0.0695	0.118	0.112	0.073	0.070	1/16	0.031	0.625
2	0.0860	0.0822	0.140	0.134	0.086	0.083	5/64	0.038	0.625
3	0.0990	0.0949	0.161	0.154	0.099	0.095	5/64	0.044	0.625
4	0.1120	0.1075	0.183	0.176	0.112	0.108	3/32	0.051	0.750
5	0.1250	0.1202	0.205	0.198	0.125	0.121	3/32	0.057	0.750
6	0.1380	0.1329	0.226	0.218	0.138	0.134	7/64	0.064	0.750
8	0.1640	0.1585	0.270	0.262	0.164	0.159	9/64	0.077	0.875
10	0.1900	0.1840	0.312	0.303	0.190	0.185	5/32	0.090	0.875
1/4	0.2500	0.2435	0.375	0.365	0.250	0.244	3/16	0.120	1.000
5/16	0.3125	0.3053	0.469	0.457	0.312	0.306	1/4	0.151	1.125
3/8	0.3750	0.3678	0.562	0.550	0.375	0.368	5/16	0.182	1.250
7/16	0.4375	0.4294	0.656	0.642	0.438	0.430	3/8	0.213	1.375
1/2	0.5000	0.4919	0.750	0.735	0.500	0.492	3/8	0.245	1.500
5/8	0.6250	0.6163	0.938	0.921	0.625	0.616	1/2	0.307	1.750
3/4	0.7500	0.7406	1.125	1.107	0.750	0.740	5/8	0.370	2.000
7/8	0.8750	0.8647	1.312	1.293	0.875	0.864	3/4	0.432	2.250
1	1.0000	0.9886	1.500	1.479	1.000	0.988	3/4	0.495	2.500
1-1/4	1.2500	1.2336	1.875	1.852	1.250	1.236	7/8	0.620
1-1/2	1.5000	1.4818	2.250	2.224	1.500	1.485	1	0.745

Metric Socket Head Cap Screws ISO 4762

Hardness	Grade 12.9: Rockwell C39-44 (Vickers HV 385-435)
Proof Load	1,100 N/mm² minimum
Tensile Strength	1,220 N/mm² minimum
Elongation	8% minimum

Dimensions in mm

Size	Body Dia Max	Body Dia Min	Thread Pitch	Thread Length is Min	Head Diameter	Head Height	Key Size	Socket Depth
Size	M1.6	1.60	1.46	0.35	15	3	1.7	1.5	0.7
M2	2.00	1.86	0.4	16	3.8	2	1.5	1
M2.5	2.50	2.36	0.45	17	4.5	2.5	2	1.1
M3	3.00	2.86	0.5	18	5.5	3	2.5	1.3
M4	4.00	3.82	0.7	20	7	4	3	2
M5	5.00	4.82	0.8	22	8.5	5	4	2.5
M6	6.00	5.82	1.0	24	10	6	5	3
M8	8.00	7.78	1.25	28	13	8	6	4
M10	10.00	9.78	1.5	32	16	10	8	5
M12	12.00	11.73	1.75	36	18	12	10	6
M14	14.00	13.73	2.0	40	21	14	12	7
M16	16.00	15.73	2.0	44	24	16	14	8
M20	20.00	19.67	2.5	52	30	20	17	10
M24	24.00	23.67	3	60	36	24	19	12
M27	27.00	26.48	3	66	40	27	19	13.5
M30	30.00	29.67	3.5	72	45	30	22	15.5

Button Socket Head Cap Screws

Button Socket Head Cap Screws are low-profile screws typically used when aesthetics are a concern. This is because the domed head provides a lower profile and smoother surface than a traditional socket head cap screw. The screw comes alloy steel or stainless steel, both of which are incredibly durable and resistant to wear and tear.

Specifications on dimensions for inch sizes are found within ASME B18.3 and ASTM F835 and stainless steel can be found in ASTM F879. Metric size specifications follow ISO 7380.

Button Socket Head Cap Screw ASME B18.3

	A		H		J
Size	Head Diameter		Head Height		Hex Key Size	Max Standard Length
Size	Max	Min	Max	Min	Hex Key Size	Nominal
4	0.213	0.201	0.059	0.051	1/16	0.50
6	0.262	0.250	0.073	0.063	5/64	0.63
8	0.312	0.298	0.087	0.077	3/32	0.75
10	0.361	0.347	0.101	0.091	1/8	1.00
1/4	0.437	0.419	0.132	0.122	5/32	1.00
5/16	0.547	0.527	0.166	0.152	3/16	1.00
3/8	0.656	0.636	0.199	0.185	7/32	1.25
1/2	0.875	0.851	0.265	0.245	5/16	2.00
5/8	1.000	0.970	0.331	0.311	3/8	2.00

ASTM F835

Hardness	4 thru 1/2” diameter: Rockwell C39 - 44 5/8” diameter: Rockwell C37 - 44
Tensile Strength	4 thru 1/2” diameter: 145,000 psi 5/8” diameter: 135,000 psi
Elongation	8% minimum
Reduction of Area	35% minimum

Metric Button Socket Head Cap ISO 7380

	A		H		J
Size	Head Diameter		Head Height		Hex Key Size
Size	Max	Min	Max	Min	Hex Key Size
M2	3.50	3.25	1.30	1.10	1.3
M2.5	4.50	4.25	1.50	1.24	1.5
M3	5.70	5.40	1.65	1.40	2.0
M4	7.60	7.24	2.20	1.95	2.5
M5	9.50	9.14	2.75	2.50	3.0
M6	10.70	10.50	3.30	3.00	4.0
M8	14.00	13.57	4.40	4.10	5.0
M10	17.50	17.07	5.50	5.20	6.0
M12	21.00	20.48	6.60	6.25	8.0

Tensile Strength 10.9	150,800 psi
Tensile Strength 12.9	172,000 psi
Tensile Strength A2 (304 Stainless)	100,000 psi
Tensile Strength A4 (316 Stainless )	100,000 psi

Flat Socket Head Cap Screws

Flat Socket head cap screws are perfect for jobs that require strong, flush-mounted fasteners. The countersunk head means the screw sits flush with the surface, so it won’t catch on objects or interfere with moving parts. In addition, flat socket heads offer high tensile strength and strong clamping force.

These socket screws are available in both alloy steel and stainless steel, with inch size specifications in accordance with ASME B18.3. Mechanical specifications for alloy follow ASTM F835 and stainless follows ASTM F879. Metric size dimensions conform to DIN 7991 and are available in alloy and stainless steel.

Metric Button Socket Head Cap ISO 7380

	D		A		H	J
Size	Body Diameter		Head Diameter		Head Height	Hex Key Size
Size	Max	Min	Sharp Max	Abs. min.	Head Height	Hex Key Size
4	0.1120	0.1075	0.255	0.218	0.083	1/16
6	0.1380	0.1329	0.307	0.263	0.097	5/64
8	0.1640	0.1585	0.359	0.311	0.112	3/32
10	0.1900	0.1840	0.411	0.359	0.127	1/8
1/4	0.2500	0.2435	0.531	0.480	0.161	5/32
5/16	0.3125	0.3053	0.656	0.600	0.198	3/16
3/8	0.3750	0.3678	0.781	0.720	0.234	7/32
1/2	0.5000	0.4919	0.938	0.872	0.251	5/16
5/8	0.6250	0.6163	1.188	1.112	0.324	3/8
3/4	0.7500	0.7406	1.438	1.355	0.396	1/2
Tolerance on Length		Screw Size		Screw Length
		Screw Size		Up to 1"	Over 1"-2-1/2	Over 2-1/2"
		4 thru 3/8		-0.030	-0.040	-0.06
		1/2 thru 3/4		-0.030	-0.060	-0.08

ASTM F835

Hardness	4 thru 1/2” diameter: Rockwell C39 - C44 5/8” diameter and larger: Rockwell C37 – C44
Yield Strength	5/8” diameter and larger: 153,000 psi
Tensile Strength	4 thru 1/2” diameter: 145,000 psi 5/8” diameter and larger: 135,000 psi
Elongation	8% minimum (over 1/2” diameter)
Reduction of Area	35% minimum (over 1/2” diameter)

Flat Socket Head Cap Screw DIN 7991

	A	H
Size	Head Diameter	Head Height	Countersunk Angle	Thread Length	Hex Key Size
Size	Max	Max	Countersunk Angle	Thread Length	Hex Key Size
M3	6	1.7	90°		2.0
M4	8	2.3	90°		2.5
M5	10	2.8	90°		3.0
M6	12	3.3	90°	24	4.0
M8	16	4.4	90°	28	5.0
M10	20	5.5	90°	32	6.0
M12	24	6.5	90°	36	8.0
M16	30	7.5	90°	44	10.0
M20	36	8.5	90°	52	12.0

Tensile Strength 10.9	150,800 psi
Tensile Strength 12.9	172,000 psi
Tensile Strength A2 (304 Stainless)	100,000 psi
Tensile Strength A4 (304 Stainless)	100,000 psi

Socket Set Screws

Socket Set screws feature a headless design and are tightened with Hex Keys (Allen wrenches). They’re typically used to prevent relative motion or rotation between parts, making them the ideal solution for securing shafts, pulleys, and gears.

Socket Set Screws ASME B18.3

	C		Half Dog Point				R	Y	J
Size	Cup & Flat Pt. Dia		P Dia		Q Len		Oval Pt Radius	Cone Pt. 90° at this Length	Hex Key Size
Size	Max	Min	Max	Min	Max	Min	Oval Pt Radius	Cone Pt. 90° at this Length	Hex Key Size
4	0.061	0.059	0.075	0.070	0.048	0.026	0.094	0.19	0.05
6	0.074	0.064	0.092	0.087	0.038	0.032	0.104	0.19	1/16
8	0.087	0.076	0.109	0.103	0.043	0.037	0.123	0.25	5/64
10	0.102	0.088	0.127	0.120	0.049	0.041	0.142	0.25	3/32
1/4	0.132	0.118	0.156	0.149	0.067	0.059	0.188	0.31	1/8
5/16	0.172	0.156	0.203	0.195	0.082	0.074	0.234	0.38	5/32
3/8	0.212	0.194	0.250	0.241	0.099	0.089	0.281	0.44	3/16
7/16	0.252	0.232	0.297	0.287	0.114	0.104	0.328	0.5	7/32
1/2	0.291	0.270	0.344	0.334	0.130	0.120	0.375	0.57	1/4
5/8	0.371	0.347	0.469	0.456	0.164	0.148	0.469	0.75	5/16
3/4	0.450	0.425	0.562	0.549	0.196	0.180	0.562	0.88	3/8
Tolerance on Length				Nominal Screw Length
				Up to 0.63, incl.		Over 0.63 to 2, incl.		Over 2 to 6, incl.
				+/-0.01		+/-0.02		+/-0.03

ASTM F880

Condition	Cold Worked
Hardness	Rockwell B96-C33

ASTM F912

Heat Treatment	Screws shall be heat-treated by oil quenching from above the transformation temperature and then tempered at a temperature sufficient to meet the hardness requirements listed below
Hardness	Rockwell C45-53

Points

Cup Point

Cup points are the most common type of point. When a point isn’t specified, you can assume it’s a cup point. They are utilized against hardened shafts or when frequent adjustments are needed but no locking mechanism is required.

Knurl Point

Knurl points are set screws that are similiar to cup point, but they’re used when vibration might be an issue. Knurls lock onto the seating material to prevent the screws from loosening.

Cone Point

Cone points set screws are used to secure components in a fixed position. They can also be used for pivots and fine adjustments.

Oval Point

Oval points are frequently used when a project may require adjustments. They’re also ideal in applications where the point meets the mating part at an angle.

Dog Point

Marshall Sales offers two different dog points: Half Dog and Full Dog. Half Dogs are more common but both can be used to permanently secure parts together. Dog points are often set into drilled holes and can be used instead of a dowel pin.

Flat Point

Flat Point set screws are a great choice when parts may frequently need to be reset. This is because the screw causes very minor damage to the part it seats against.
Dimensional specifications for inch-socket set screws follow ASME B18.3 standards. Please note the length of the socket set screw referred to in the chart is the overall length, including the tip. The mechanical properties for alloy follow ASTM F912 and stainless follows ASTM F880.

Brass & Nylon Tip

Brass and nylon tip set screws are specifically designed for applications where it’s crucial to protect surfaces. These screws are ideal for securing components or parts to a shaft or other surface without causing damage or leaving a mark.

Find the Right Part

Our knowledgeable staff is readily available for questions, concerns, and to help you find the right sockets and points for your project.