AS85049 Backshells: Technical Specifications, Part Numbering, and Selection Guide
Note: AS85049 backshells were formerly known under the military specification M85049. The AS85049 standard has replaced M85049 and is maintained by SAE International. Both designations are often used interchangeably, and understanding the correlation is important for proper component selection.
Understanding AS85049/M85049 Backshells
AS85049/M85049 backshells are critical components used in conjunction with circular connectors to provide strain relief, environmental sealing, and electromagnetic interference (EMI) shielding. They are extensively used in military, aerospace, and industrial applications where reliability and durability are paramount.
This guide provides detailed information to assist engineers and technicians in selecting the appropriate backshells for their specific applications.
Interactive Backshell Selector
Use our backshell selector tool to build complete AS85049 part numbers based on your requirements:
- Backshell Styles: Straight, 45°, and 90° configurations
- Environmental Options: Environmental sealing or non-environmental
- EMI/RFI Shielding: Shielded or unshielded options
- Materials and Finishes: Select based on environmental conditions and compatibility
- Cable Support: Strain relief types and accessories
The selector simplifies identifying the right backshell for your application, ensuring compatibility and compliance with standards.
AS85049/M85049 Part Numbering System
The AS85049 (formerly M85049) part numbering system encodes critical information about the backshell's characteristics. Understanding this system is essential for selecting the correct component.
Part Number Format
The general format is:
AS85049/XXX - XX - X - XX - X
- AS85049/XXX: Basic specification number with slash sheet detail (e.g., AS85049/1). Formerly M85049/1.
- Designator Code: Indicates backshell design characteristics.
- Material Code: Specifies the construction material.
- Finish Code: Indicates plating or finish applied.
- Shell Size Code: Corresponds to connector shell size.
- Option Codes: Additional features or modifications.
Example Part Number Breakdown
Example: AS85049/1 - A - W - 20 (formerly M85049/1 - A - W - 20)
- AS85049/1: Backshell per slash sheet 1 (e.g., straight, non-environmental).
- A: Material code ("A" for aluminum alloy).
- W: Finish code ("W" for cadmium over nickel with olive drab chromate).
- 20: Shell size code (compatible with size 20 connectors).
Backshell Styles (Slash Sheets)
The slash sheet number defines the backshell style. The AS85049 slash sheets correspond directly to the former M85049 slash sheets.
| AS85049 Slash Sheet | M85049 Slash Sheet | Description |
|---|---|---|
| AS85049/1 | M85049/1 | Straight, Non-Environmental |
| AS85049/2 | M85049/2 | 45°, Non-Environmental |
| AS85049/3 | M85049/3 | 90°, Non-Environmental |
| AS85049/31 | M85049/31 | Straight, Environmental |
| AS85049/32 | M85049/32 | 45°, Environmental |
| AS85049/33 | M85049/33 | 90°, Environmental |
Material Codes
| Code | Material | Description |
|---|---|---|
| A | Aluminum Alloy | Lightweight, corrosion-resistant |
| B | Brass | Good mechanical strength |
| C | Stainless Steel | High strength, corrosion-resistant |
| D | Aluminum Bronze | Excellent corrosion resistance in marine environments |
| K | Composite | Non-metallic, lightweight |
Finish Codes
| Code | Finish | Description |
|---|---|---|
| N | Anodize (Non-conductive) | Enhanced corrosion resistance |
| F | Electroless Nickel | Corrosion-resistant, EMI shielding |
| W | Cadmium Olive Drab over Nickel | Excellent corrosion resistance, military standard |
| M | Nickel Fluorocarbon Polymer | Corrosion-resistant, low friction |
| Z | Zinc Nickel Black | Non-reflective, high corrosion resistance |
Shell Size Codes
Shell sizes correspond to standard connector sizes:
| Code | Shell Size |
|---|---|
| 08 | Size 8 |
| 10 | Size 10 |
| 12 | Size 12 |
| 14 | Size 14 |
| 16 | Size 16 |
| 18 | Size 18 |
| 20 | Size 20 |
| 22 | Size 22 |
| 24 | Size 24 |
Technical Resources and Documentation
Access official specifications, technical manuals, and catalogs:
Important Documentation
- Backshell Style Definitions and Part Numbering Guides
- Material and Plating Specifications
- Environmental Sealing Guidelines
- Installation and Assembly Instructions
- Performance and Testing Standards
These resources are essential for ensuring proper selection and adherence to industry standards.
Selection Guide and Best Practices
Backshell Selection Process
When selecting a backshell, consider the following factors:
- Connector Compatibility: Ensure the backshell matches the connector's shell size and coupling thread.
- Environmental Conditions: Determine if environmental sealing is required based on exposure to moisture, dust, or chemicals.
- EMI/RFI Requirements: Assess the need for shielding to maintain signal integrity.
- Mechanical Stress: Evaluate the need for strain relief to protect cable integrity.
- Material Compatibility: Select materials and finishes compatible with the operational environment to prevent corrosion.
Installation Best Practices
Proper installation ensures optimal performance:
- Follow Manufacturer Guidelines: Adhere to specific installation instructions provided by the manufacturer.
- Use Appropriate Tools: Utilize the correct tools for assembly, such as torque wrenches and banding tools.
- Inspect Components: Check for defects or damage before installation.
- Cable Preparation: Prepare cables according to specifications, ensuring proper shielding and insulation.
- Verify Sealing: Confirm that environmental seals are properly seated and intact.
Maintenance and Inspection
Regular maintenance extends the service life:
- Periodic Inspection: Regularly inspect backshells for signs of wear, corrosion, or damage.
- Environmental Seals: Check seals for degradation and replace as necessary.
- Secure Connections: Ensure all coupling mechanisms remain tight and secure.
- Cleaning: Clean with appropriate solvents that do not harm materials or finishes.
Compliance and Standards
AS85049/M85049 backshells comply with key industry and military standards:
- SAE AS85049: Governs design, materials, and performance requirements.
- MIL-DTL-M85049: Legacy military specification for backshells.
- MIL-DTL-38999: Ensures compatibility with military-grade connectors.
- MIL-STD-202: Defines test methods for electronic components.
- MIL-STD-1344: Specifies test methods for electrical connectors.
- RoHS Compliance: Many backshells meet restrictions on hazardous substances.
Contact Information
If you require further assistance or have specific inquiries:
Email: [Email Protected]
Our technical support team is available to help with your AS85049/M85049 backshell needs.