Product Description
Black oxide steel socket head shoulder screws are considered grade 12 (12.9). The socket head shoulder screws offer a very high tensile strength of 170,000 psi when tested lengthwise.
The shoulder screws are offered in both black oxide and stainless steel. The steel screws are mildly corrosion resistant in dry environments as the screws are covered with a light protective oil coating.
Stainless steel offers the best protection against deterioration but has caveats. The tensile strength of type 316 stainless steel is only slightly stronger than un-hardened grade 2 ferrous steel. Also, please be aware that when combining stainless steel fasteners; especially stainless lock nuts regardless the thread type or bolt diameter, it's recommended to coat the male bolt threads in never-seez before assembly as galling can occur and cause the nut to fuse to the bolt during installation/disassembly, leaving the threads looking melted as the nut seizes in place and any further turning of the wrench just shears the bolt in half.
To correctly identify/specify the length "L" of a socket head shoulder screw, measure under the head like a standard head screw but only include the shoulders length, not the threaded portion as it is not added to the screws overall length when describing them.
When selecting inch threads, thread pitch is measured by counting every thread contained within 1" and is spoken as "threads per inch" (i.e. 3/8"-16 TPI)
When selecting metric threads, thread pitch is measured from one thread peak to the next in millimeters (i.e. M10-1.25mm). Many metric threaded bolts are cut with fine and extra-fine threads which further necessitate the need for proper thread identification before ordering. Vernier calipers and thread gauges proove invaluable for this task.
Click this link for a detailed Wiki explanation on the Unified Thread Standard
Click this link for a detailed Wiki explanation on the Metric Thread Standard
Fasteners meet ISO 7379 comply with specifications and testing requirements for material quality.
Brighton Best General Catalog
Box quantity shown in drop down
Box quantity shown in drop down Sold as each
Grade 12.9
Class Fit 3A
Head type Shoulder
Hardness range Rockwell 32-43
Standard ISO 7379
Standard ASME/ANSI B18.3-1986 & ASTM A574-92A
