Zinc Plated Hexagonal Socket Head Cap Screw, UNC 1/2-13 x 1.75 for SAE 4 Bolt Flange

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.