Machine Screw Hex Nuts 316 Stainless Steel Smallest Size: #4-40 Largest Size: #12-24 Available in UNC Coarse or UNF Fine thread Known as machine screw nuts, ms nuts, or machine nuts 316 Stainless steel is corrosion resistant and well suited for applications in severe, harsh, or marine environments Machine nuts are used with machine screws to mechanically connect materials together. This type of nut is used with smaller machine screw sizes under 1/4". Hex machine nuts are used for many fastening applications. Machine screw nuts are often used with hex cap screws, socket screws, and bolts.