Wing nut is a nut with a metal wing on each side, which can be tightened by hand instead of tools. HCH Fasteners. Various types of wing nuts are available. We offer the following types of wing nuts: Type A: They are also called cold forged butterfly nuts. They are available in light, regular and heavy series. HCH Fasteners. 18-8 stainless steel (300 series), 316 stainless steel, aluminum, brass, silicon bronze, and steel (zinc and nickel plated) are available. We can also provide various types of coatings, such as black zinc, black oxide, zinc yellow, etc. Type C: also known as die cast wing nut. They are galvanized. They are stronger than stainless steel butterfly nuts, but they are corrosion resistant. We provide standard washer bases that need to be mounted on larger bearing surfaces. Type D: They are also called wing nuts. HCH Fasteners, Inc., has options for steel zinc, black oxide, and washer seats. They are similar to cold forged butterfly nuts, but their strength is not high. Metric butterfly nut: HCH Fasteners, metric DIN 315 butterfly nut is also available. We offer stainless steel (A2 and A4) and forged steel zinc.