Aeronautical Standard Plain Castle Nut | AN310-4

• Thread Direction: Right-hand
  
• Thread Class: 3b
  
• Surface Treatment Specification: Qq-p-416 type 2 class 3 federal specification single treatment response
  
• Surface Treatment: Cadmium
  
• Nut Style: Hexagon castellated
  
• Nut Height: Between 0.265 inches and 0.297 inches
  
• Material: Steel
  
• Surface Type: Chamfered or washer faced
  
• Thread Qty Per Inch (tpi): 28
  
• Thread Series: Unf (fine thread)
  
• Thread Size: 0.250 inches
  
• Width Across Flats: Between 0.428 inches and 0.440 inches