STS Industrial - Bolts & Screws

 

FLAT SOCKET HEAD CAP SCREWS

GOVERNING STANDARDS:
ASTM F835 Covers the mechanical and material requirements for alloy steel button and flat socket head cap screws.
ASME B18.3 Covers the complete general and dimensional data for various types of hexagon socket cap screws, shoulder screws and set screws.
ASME B1.1 UNRC & UNRF Class 3A (Class 2A above 1″) Specifies the thread form, series, class, allowance, tolerance, and designation for unified rounded root screw threads.

 

APPLICATIONS:

Flat socket head cap screws (also known as flat head Allen screws) have a countersunk head with a flat top surface and hexagon recess. Flat socket head cap screws are commonly used in applications in which it is necessary to recess the head of the fastener flush with the surface. The hex recess, or Allen drive is more robust than many other drive types. 

 Flat Socket Head Cap Screw Head

MATERIAL PROPERTIES:
Alloy Steel, Quenched and Tempered

DIAMETER

PROOF LOAD

YIELD STRENGTH

TENSILE STRENGTH

CORE HARDNESS

Through 1/2″ 145,000 psi C39 to C44
5/8″ and Larger 135,000 psi C37 to C44
Elongation 8% Minimum (Applies to machined specimens over 1/2″ diameter of length at least 4 X Diameter)
Reduction of Area 35% Minimum (Applies to machined specimens over 1/2″)
Material strengths listed are minimum acceptable per governing standard. Core hardness based on Rockwell scale.
DIMENSIONAL SPECIFICATIONS:

 

Flat Socket Head Cap Screw Dimensional Data

Flat Socket Head Cap Screws Length Specifications

 

Sources: ASTM Standards for Mechanical Fasteners and Related Processes 2nd Edition, Inch Fastener Standards 8th Edition, Kanebridge Fastener Reference Guide 4th Edition

Note: All material included on this page is informational only, and should not be used as one’s sole source for design purposes. STS Industrial, Inc. and its affiliates do not guarantee the accuracy of the information on this site, and retain no liability for the use or misuse of the information contained on this site.