Customized Bonnell Coil Spring Unit with High Carbon Steel Wire, 4-8 Turns, and 60-90mm Spring Height for Mattress

Bonnell coil spring units are manufactured from high-carbon steel wire, offering excellent tensile strength and hardness for durable mattress support systems.

Bonnell coils represent the oldest and most traditional type of mattress spring system. These hourglass-shaped, knotted wire springs are connected in a continuous grid by helical wires (strings of smaller coils). Known for their firm support and cost-effectiveness, Bonnell springs remain a popular choice for innerspring mattress construction.

• Wire Gauge (Thickness): The most critical factor determining firmness
  • Lower gauge number = thicker wire = firmer feel (e.g., 12.5 gauge)
  • Higher gauge number = thinner wire = softer feel (e.g., 15 gauge)
  • Common range: 12.5 ga (~1.7mm) to 15 ga (~1.4mm)
• Wire Material: High-carbon steel for strength and resilience, with optional powder coating or electrogalvanizing for rust prevention

• Spring Height: Individual coil height
  • Common heights: 5", 6", 7", 8" (10-inch less common but available)
  • Taller springs provide softer feel and suit thicker mattresses
• Coil Count: Total number of springs in the unit
  • Queen size (60"x80") typically contains 250-350 Bonnell coils
  • Higher coil count offers more precise support and firmer feel
• Tempering (Heat Treatment): Standard process that increases durability and prevents sagging