1/4-20 Hex Socket Shoulder Bolts BS 2470 Black Oxide Grade 12.9

Description

1/4-20 hex socket shoulder bolts are cost-saving construction elements for a wide variety of different uses. The maximum tightening torque must not be defined by strength class 12.9, it is instead limited by the relatively small bearing points (shoulders) and by the recesses at the transition point from the diameter of the shoulder to the thread diameter and the diameter of the shoulder to the head diameter. Ever Hardware provides custom-made fasteners and customizable packaging.

1/4-20 hex socket shoulder bolts are a screw with an unthreaded shoulder that is larger in diameter than the 1/4 imperial threads. Also known as stripper bolt. The cylindrical shoulder that allows for the rotation of attached parts like pulleys, gears, moving parts of engines and mechanical assemblies, and rolling wheels. Shoulder bolt also used to attach stripper plates. The socket head enables high torque fastening with limited clearance.

Black oxide or blackening is a conversion coating for ferrous materials, stainless steel, copper and copper-based alloys, zinc, powdered metals, and silver solder. It is used to add mild corrosion resistance, for appearance and to minimize light reflection. To achieve maximum corrosion resistance the black oxide must be impregnated with oil or wax. One of its advantages over other coatings is its minimal buildup.
The five basic steps for the black oxide conversion coating are clean; rinse; black oxide; rinse; supplementary coating (after-finish). If rust or scale is present on the part, additional steps such as acid pickling or alkaline de-scaling may have to be added before oxidising. Neutralizing and/or further rinsing may be necessary on assemblies and parts with blind holes to eliminate “flowering” or bleed-out. Black oxide cannot be produced over plated parts (zinc, nickel, chromium, cadmium, phosphate). This plating must be stripped prior to the black oxide process.