MS35206-280 – Pan Head Phillips Aerospace Machine Screw
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The MS35206-280 is a high-strength, precision-engineered aerospace machine screw designed for structural and non-structural fastening in both civilian and military aircraft. Part of the MIL-DTL-32258 (formerly MS35206) specification, this fastener features a pan head design with a Phillips recessed drive, providing a low-profile finish with a wide bearing surface. This specific dash number (-280) denotes a #10-32 fine-thread screw with a nominal length of 1.000 inch, manufactured from carbon steel and treated with a cadmium plating for superior corrosion resistance and lubricity.
In the aerospace environment, the MS35206-280 is prized for its versatility. It is frequently used in avionics rack mounting, interior cabin assembly, and secondary structural attachments where a protruding head is permissible. Unlike commercial-grade screws, the MS35206 series undergoes rigorous quality control to ensure consistent grain flow in the forged head and precise thread tolerances (Class 2A fit), preventing failure under the high-vibration and thermal-cycling conditions characteristic of flight operations.
Key Features
Cold-Headed Forged Construction: The screw head and shank are forged as a single unit, ensuring continuous grain flow that maximizes resistance to fatigue cracking at the head-to-shank junction.
Cadmium Plate (Type II, Class 3): Coated with a gold-colored chromate finish (Cadmium) which provides an exceptional sacrificial barrier against corrosion and prevents galvanic reaction when mated with aluminum airframe components.
Pan Head Geometry: Provides a flat bearing surface for even load distribution, making it ideal for securing thin-gauge sheet metal or composite panels without the need for a separate washer in low-stress applications.
Precision Fine Threads (Class 2A): Features #10-32 UNF threads, offering higher vibration resistance and finer adjustment capabilities than coarse-thread equivalents.
Phillips Recess Drive: Designed for compatibility with standard aerospace torque-limiting drivers, allowing for rapid installation and removal during routine maintenance.
Technical Specifications
Part Number: MS35206-280
Specification: MIL-DTL-32258 (Superseding MS35206)
Thread Size: #10-32 (0.1900-32 UNF-2A)
Length: 1.000 Inch (measured from under the head to the tip)
Head Type: Pan Head
Drive Type: Phillips Recess
Material: Carbon Steel (Minimum tensile strength of 60,000 PSI)
Finish: Cadmium Plate per QQ-P-416, Type II, Class 3 (Gold/Yellow Chromate)
Thread Direction: Right-Hand
Point Style: Plain (Flat or slightly chamfered)
Aircraft Compatibility
Cessna, Beechcraft, & Piper: Widely used in airframe interior panels, cowling attachments, and fairings.
Boeing & Airbus: Common in cabin monuments, stowage bins, and non-pressurized secondary structures.
General Dynamics / Lockheed Martin: Standard hardware for various military GSE and avionics bay doors.
Note: Always refer to the Illustrated Parts Catalog (IPC) or the specific Engineering Drawing for your aircraft to ensure the correct fastener length and material grade are utilized.
Applications
The MS35206-280 is primarily used in Shear and Light-Tension Joints. Common applications include:
Avionics Mounting: Securing trays and units within a radio rack or instrument panel.
Interior Assemblies: Fastening floor boards, sidewall panels, and overhead bins.
Electrical System: Mounting terminal strips, junction boxes, and wire harness clamps (Adel clamps).
Why Choose MS35206-280?
Choosing a genuine MIL-SPEC fastener like the MS35206-280 is critical for maintaining type certification. Commercial "big-box" hardware lacks the metallurgical traceability and plating thickness required to survive the aerospace environment. Use of non-certified fasteners can lead to hydrogen embrittlement or rapid oxidation, potentially causing the screw to shear under vibration—leading to loose panels or localized structural failure.
The mechanical integrity of the MS35206-280 is governed by the relationship between its tensile stress area and its installation torque. As a fine-thread (#10-32) fastener, it possesses a larger minor diameter compared to coarse threads, granting it superior shear strength. The Cadmium Type II finish is not merely for aesthetics; it provides a low coefficient of friction, allowing for a more predictable torque-tension relationship. This ensures that when the screw is torqued to its nominal value, the resulting preload (clamping force) is sufficient to prevent the joint from undergoing fretting wear under cyclic aerodynamic loading. Furthermore, the Phillips drive design is engineered to "cam-out" at extreme torque levels, acting as a secondary safeguard to prevent the over-tensioning and subsequent necking of the steel shank.
Note: This is a standard aerospace fastener. Ensure that the mating nut-plate or tapped hole is clean and free of debris before installation. Do not reuse screws that show signs of thread galling or drive recess deformation. Installation must be performed in accordance with the standard torque tables found in FAA AC 43.13-1B, Chapter 7, unless otherwise specified by the airframe manufacturer.