Product Description
Black oxide steel socket head cap screws are considered grade 12 (12.9) and are much stronger than the flexible grade 5 (8.8) preferred for shear pins and general use or the stiffness of grade 8 (10.9) fasteners commonly deployed as frame bolts on semi trucks. For specific socket head tensile strengths, please refer to the chart in the image carousel.
Black oxide steel screws are mildly corrosion resistant in dry environments as the screws are covered with a light protective oil coating.
Baked zinc plated screws aid in the resistance to corrosion and are an economical substitute to stainless while still maintaing the high tensile strength of steel.
Stainless steel offers the best protection against deterioration among the three fasteners 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 measure the length "L" of any socket head cap screw, you must measure under the head on standard/button/low head screws and include the head when measuring flat head (countersunk) screws.
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 A2 (18-8) ASME B18.3-2003 ASTM F837-02a (CW1) and comply with specifications for dimensional standards.
Brighton Best General Catalog
Box quantity shown in drop down
Box quantity shown in drop down Sold as each
Class Fit 3A
Head type Standard
Standard A2 (18-8) ASME B18.3-2003 ASTM F837-02a (CW1)
