4-40 x 1 18-8 Stainless Steel Button Head Socket Cap Screw with Nylon Insert provides a broad bearing face and smooth exposed dome for thin covers or frequently handled surfaces. The locking pellet adds a prevailing-torque feature while the internal hex drive keeps installation compact from the top side.

The low-dome head is not a countersunk style; seating and clearance should be checked against the mating surface and surrounding equipment. This size is often reviewed for cleaning-cycle equipment, stainless guards, and fixture hardware when stainless material, a button head, and a locking pellet are all specified.

18-8 stainless is practical for washdown-adjacent machinery, packaging equipment, and outdoor or high-touch hardware where the service environment is not chloride-critical. If strength matters more than stainless material, Alloy Steel Button Head Socket Cap Screws with Nylon Insert may be the better route. Since 1962, Cold Headers has helped industrial buyers locate specialty socket products for production, repair, and replacement requirements.

Technical Highlights

• Material: 18-8 Stainless Steel
• Thread Size: 4-40
• Length: 1 in.
• Head Style: Button Head
• Drive Type: Internal Hex
• Locking Feature: Nylon insert providing prevailing torque
• Nylon Insert Diameter (P): 1/16 in.
• Nylon Insert Location (N): 7/64 in. +/-1/2 pitch
• Head Dimensions: ASME B18.3

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