Wing Nut (Butterfly Nut)
Direct Answer
The Wing Nut (Butterfly Nut, standardized under DIN 315 and ASME B18.6.9) features two large ergonomic metallic side projections ('wings') extending vertically from the central threaded boss. Designed for rapid, tool-free tightening and loosening by hand, it is the standard fastener on stage lighting C-clamps, drum set cymbal stands, and battery terminals.
Source: DIN 315 (German Form / American Form) / ASME B18.6.9
Specs
| Standard Specifications | DIN 315 (Type D ductile cast / Type F forged) / ASME B18.6.9 (Type A/B/C) |
| Wing Geometry | Two opposing curved radial wings for manual two-finger leverage |
| Tightening Method | 100% Tool-free manual finger tightening |
| Common Materials | Stainless steel (A2/A4), zinc-plated malleable iron, brass, nylon plastic |
| Clamping Torque Limitation | Low manual torque (~1.5 to 5 N·m depending on finger grip strength) |
| Primary Applications | Drum kits (cymbal stands), stage theatrical lighting clamps, air filter covers, marine battery terminals |
Tool-Free Field Adjustment
Wing nuts are engineered specifically for assemblies that require frequent disassembly or positioning adjustments without tools. In theatrical and concert stage lighting, technicians adjust heavy spotlight angles and focus barrels suspended high overhead on lighting trusses using M8 or M10 DIN 315 wing nuts.
DIN 315 German vs American Style Wings
- German Form (DIN 315): Features rounded, gracefully curved wing contours with smooth radiuses.
- American Form (ASME Type A): Features taller, squarer wings with flat top ridges providing slightly higher finger purchase.