4-40 x 1 1/2 18-8 Stainless Steel Flat Head Cap Screw with Nylon Insert helps avoid length-selection errors common when switching from socket head cap screws. For example, a 1/4-20 x 1 flat head screw fits within one inch overall because the head is included in that length. When installed in the correct countersink, the flat head leaves little exposed hardware for covers, panels, or moving material to catch.

For display faces, fixture panels, or visible stainless hardware, confirm countersink geometry, thread engagement, and whether the nylon insert suits the service conditions. For higher preload potential and a deeper socket, review 1960 Series 18-8 SHCS with Nylon Insert.

The nylon pellet presses against the mating thread to provide prevailing torque without changing the countersunk head geometry. The locking pellet is installed in-house on supported socket-cap sizes, with unusual requests handled through quoting.

Technical Highlights

• Material: 18-8 Stainless Steel
• Thread Size: 4-40
• Length (overall - includes head): 1 1/2 in.
• Head Style: 82° Countersunk Flat
• 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.