4-40 x 5/16 Flat Point Alloy Steel Socket Set Screw with Nylon Insert combines a flat bearing point, internal hex drive, and nylon locking pellet for adjustable machine settings. The flat point clamps by friction, so it is commonly chosen for shafts that should not be intentionally marked by a biting point. Use the heat-treated alloy steel body with the nylon locking pellet where the application calls for mechanical fastening rather than stainless material.

Machine rebuilds use this family when the service record calls for alloy steel, a flat point, and a nylon insert.

The catalog keeps this family separate from plain flat point screws so the nylon insert requirement remains visible. Check thread size, length, socket size, pellet dimensions, shaft-flat condition, and surface-marking tolerance before substitution.

Technical Highlights

• Point: Flat (full bearing face)
• Material: Alloy Steel
• Thread Size: 4-40
• Length: 5/16 in.
• Drive: Internal Hex
• Hex Key Size: 0.050 in.
• Locking Feature: Nylon insert providing prevailing torque
• Nylon Insert Diameter (P): 1/16 in.
• Nylon Insert Location (N): 3/32 in., +/-1/2 pitch
• Dimensional Standard: ASME B18.3

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.