Guide to Socket Head Cap Screw Fasteners

A socket head cap screw is used to fasten two objects together when there is limited clearance between the two materials or in the assembly. These cap screws feature a hexagonal-shaped recess in the head for tightening with a hex key or Allen wrench. The advantages of socket head cap screws include high tensile strength and yield strength as well as greater shear strength when compared to hex head bolts and screws.

What Are Typical Socket Head Cap Screw Dimensions?
Typical diameters of socket head cap screws range from 0.096 inches to 0.345 inches and head heights of 0.060 inches to 0.216 inches. The range of countersink diameters is 0.074 inches to 0.218 inches. Counter-bore measurement ranges include diameters of 0.125 inches to 0.406 inches and depths of 0.060 inches to 0.216 inches.

How to Select the Correct Size of Metric Socket Head Cap Screws
Standard socket head cap screws are measured in sizes 0 through 12. When converted into metric measurements, the socket head cap screws are available in sizes ranging from 0.400 millimeters in diameter to 2.6 millimeters in diameter for the heads and lengths of 6 millimeters to 45 millimeters. You will need a corresponding metric-sized wrench for tightening these fasteners.

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What Materials are Socket Head Cap Screws Made of?
Socket head cap screws are available in a wide variety of materials. Our 18-8, 316 and traditional stainless steel socket head cap screws are the most popular options for this type of fastener as the stainless steel confers a high resistance to corrosion, moisture and wear. Other materials that socket head cap screws are commonly made of include alloy steel, which offers the option for heat treatments; and plain steel, which is highly malleable.

Head Sub-types for Socket Head Cap Screws
In addition to the typical standard head for socket head cap screws, there are some specialty heads that are also available for this type of fastener. These specialty heads include button heads, which are dome-shaped and offer a recessed hexagonal fitting; flange heads, which offer a protruding edge that acts like a washer; flat heads, which are countersunk; low heads, which have head heights that are 50 percent shorter than standard; self-locking heads, which prevent turning of the screw in the presence of vibration; and vented heads, which allow gasses and liquids to ventilate through the screw.

Uses for Socket Head Cap Screws
Socket head cap screws are used for fastening together machine parts, home appliances and consumer electronics. They are used without a nut and in situations where a high amount of clamping force is required due to vibrations and motion between two parts.

We offer a wide range of sizes and materials for socket head cap screws. Our technical sales team is always available to assist you in selecting the English or metric size and ideal socket head cap screw material based on your application.