The MS51959-5 is a military-standard precision machine screw used in aircraft and aerospace assemblies where small-diameter, lightweight, and corrosion-resistant fastening is required. It features a flat (countersunk) head with Phillips drive, designed to sit flush within countersunk surfaces for smooth aerodynamic or finished panel applications.

This screw is commonly used in aircraft interior structures, fairings, access panels, instrumentation, and lightweight airframe assemblies. It provides reliable fastening in low-to-medium load applications where flush mounting and vibration resistance are important.

Manufactured to MS specifications, it is typically made from 18-8 or 300-series stainless steel with passivated corrosion protection, ensuring durability in aviation environments exposed to moisture, vibration, and temperature variation.

The MS51959 series is widely used in aerospace maintenance and OEM production as a standard fastener family for flush-mounted machine screw applications.

Key features include:

MS51959-5 aerospace machine screw
Flat countersunk head (82°)
Phillips drive for standard tooling
Thread: #2-56 UNF fine thread
Stainless steel (18-8 / 300-series) construction
Passivated corrosion-resistant finish
Designed for flush installation in panels
Used in aircraft interior and light structures
Suitable for vibration and cyclic load environments
Direct replacement per MS aircraft hardware standards