S1021Z10-8 - Textron Aviation OEM Steel Self Tapping Screw

S1021Z10-8 – Textron Aviation OEM #10 x 1/2" Self-Tapping Screw (Pan Head)

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Overview

The S1021Z10-8 is a genuine Textron Aviation Original Equipment Manufacturer (OEM) self-tapping screw, manufactured to a proprietary Cessna design standard. This fastener is engineered to create its own threads when driven into a pre-drilled pilot hole in thin-gauge sheet metal structures. It is a Type A thread-forming screw, characterized by its coarse threads and sharp point, and is widely used for attaching non-structural and lightly loaded components throughout the airframe.

This screw is fabricated from zinc-plated steel for corrosion resistance and features a Pan Head with a Phillips drive. As a genuine Textron OEM part, the S1021Z10-8 is guaranteed to have the precise diameter, thread pitch, point style, and material properties required for its intended applications on Cessna aircraft, ensuring a secure and reliable fit without damaging the underlying structure.

Key Features

• Genuine Textron Aviation OEM Part: Guarantees the part is fabricated to the exact Textron engineering drawing for material, dimensions, and performance.

• Type A Thread-Forming Design: The screw plastically deforms the material of a pilot hole to form a perfectly mated thread, creating a tight, vibration-resistant joint without producing metal chips (FOD).

• Pan Head Phillips Drive: The Pan Head provides a low-profile, clean appearance with a large bearing surface, while the Phillips drive is the standard for general aviation assembly and maintenance.

• Zinc-Plated Steel: The steel body provides strength, and the zinc plating offers effective corrosion protection for interior and other protected applications.

• Designed for Thin-Gauge Sheet Metal: The Type A point and thread pitch are specifically engineered for optimal performance in thin aluminum or steel sheet (typically 0.015" to 0.050" thick).

• Standard #10 x 1/2" Size: A common size used for a multitude of attachment applications.

Technical Specifications

• Part Number: S1021Z10-8

• Component Type: Self-Tapping Screw, Type A, Pan Head, Phillips

• OEM Authority: Textron Aviation (Cessna)

• Material: Steel

• Finish: Zinc Plated

• Head Style: Pan Head

• Drive Type: Phillips

• Size: #10 (0.190 inch nominal diameter)

• Length (under head to point): 1/2 inch (0.500 inches)

• Governing Specification: Textron Aviation Engineering Drawing S1021.

Aircraft Compatibility

This OEM self-tapping screw is a standard hardware item used extensively on a vast range of Textron Aviation aircraft, particularly the Cessna piston fleet.

• Primary Textron Aviation Platforms:

  • Cessna Piston Aircraft (100, 200, 300, 400 Series)

  • Cessna Caravan Series

  • Certain non-structural applications in Cessna Citation business jets.

Note: Verification of applicability is the absolute responsibility of the installer. The aircraft's current Illustrated Parts Catalog (IPC) for its specific serial number is the final authority for confirming part number eligibility.

Applications

• Attaching interior plastic trim panels, moldings, and upholstery components.

• Securing lightweight instrument panel covers and placards.

• Fastening small, non-structural fairings, gap seals, and inspection covers to the airframe.

• Mounting lightweight brackets, clips, and clamps to sheet metal ribs and bulkheads.

• WARNING: Not for use in primary or major secondary structural applications.

Why Choose S1021Z10-8?

While seemingly a simple screw, the S1021Z10-8 is an engineered fastener. The integrity of the joint depends on the screw's ability to form threads without stripping the hole. Only the genuine Textron OEM part is guaranteed to be manufactured with the correct thread profile, hardness, and point geometry to perform this function reliably in the specified material and thickness. Using a generic, commercial-grade self-tapping screw can easily result in a stripped hole, a loose component, and potential damage to the airframe structure, creating a source of vibration and fretting.

The S1021Z10-8 is a thread-forming screw, and its function is based on the principle of cold working the parent material. Unlike a thread-cutting screw that acts like a tap to remove material, the Type A screw's tapered, widely spaced threads are designed to plastically deform the metal surrounding the pilot hole. As the screw is driven, its threads displace and extrude the sheet metal into the thread roots, forming a perfectly mated, zero-clearance internal thread. This process of cold work significantly increases the hardness and strength of the formed threads in the sheet metal. The resulting joint is exceptionally resistant to vibrational loosening because of the tight interference fit and the high residual stresses in the formed material that create a natural locking action. This method also has the critical advantage of producing no cutting debris (chips), eliminating a potential source of Foreign Object Debris (FOD) in the airframe.

Note: This is a non-structural fastener. It must be installed in a correctly sized pilot hole as specified by the maintenance or structural repair manual. Use of the correct size Phillips driver bit is required to prevent cam-out and damage to the drive recess. The screw should be driven with a low-torque, speed-controlled tool. Over-torquing will permanently strip the formed threads in the sheet metal, requiring an oversized screw or other repair. While sometimes reusable in the same hole, repeated removal and installation will degrade the holding strength.

Documentation

All technical data, including pilot hole sizes and recommended installation practices for the S1021Z10-8 screw, are proprietary to Textron Aviation. This information is contained within the official Maintenance Manual and Standard Practices documents for the applicable aircraft model. No public-facing documentation is available.