Bending Aircraft Metal

Introduction

• Part of Vancouver Community College's Provincial Instructor Diploma Program (Spring 2012).
• Focus on bending sheet metal, specifically aluminum, over 90 degrees using a bending brake.

Key Information Before Bending

1. Grain Direction
   • Aluminum has a visible grain, crucial for bending direction.
   • Information printed along the grain line for reference.
2. Material Thickness
   • Essential for calculating bend allowances and setbacks.
3. Bending Radius
   • Nose bar with a built-in radius used (e.g., 1/8 inch radius).

Specifications and Measurements

• Drawings specify lengths for both legs of the bend (e.g., 6 inches and 8 inches).
• Use a bend allowance chart to determine material usage in bends.
• Bend Allowance: Amount of material used in the bend, calculated based on radius and thickness (e.g., 0.224 for 90-degree angle).

Calculating Setback and Developed Length

• Setback (Sb): Formula = Bend radius + Material thickness (e.g., 0.165 total).
• Subtract setback from drawing length to find developed lengths of legs:
  • E.g., 6 inches - 0.165 = 5.835.
• Developed Length: Total material length needed = Sum of both leg lengths plus bend allowance.
  • E.g., 5.835 + 7.835 + 0.224 = 13.894 (less than 14 inches).

Sight Line

• Used to ensure accurate placement in the bending brake.
• Sight line positioned one radius away from bend allowance edge.
• Place an arrow to indicate the side to insert into the brake.

Bending Process

• Insert material into the brake, align with sight line.
• Bend beyond 90 degrees to account for aluminum's springiness.
• Aim for around 10% past 90 degrees to achieve the perfect bend.

Review and Conclusion

• Important factors: Material thickness, Bend radius, Grain direction.
• Follow steps to ensure accurate bending of aircraft aluminum.
• Emphasize the skill and precision required in metal bending.