UNF
Science & Engineering abbreviation · Engineering
| Stands for | Unified National Fine (thread) |
|---|---|
| Categories | Science & Engineering |
UNF stands for Unified National Fine (thread), an engineering abbreviation.
Inch-based screw thread series with more threads per inch than UNC, giving greater tensile strength for a given diameter and finer adjustment. UNF fasteners are common in aerospace, automotive and precision equipment; a 1/4-28 UNF bolt has 28 threads per inch.
Example: The brake caliper bolts are 3/8-24 UNF, so do not substitute coarse-thread hardware.
Usage notes
Fine threads resist loosening from vibration better than coarse threads but are more prone to galling and damage. An even finer series, UNEF (extra fine), is used for thin-walled parts. Metric threads are specified differently, such as M8 x 1.25.
Related abbreviations
More engineering abbreviations
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- AFUE – Annual Fuel Utilization Efficiency
- AHU – Air handling unit
- ASME – American Society of Mechanical Engineers
- ASTM – ASTM International
- BIM – Building information modeling
- BOM – Bill of materials
- CAD – Computer-aided design
- CAE – Computer-aided engineering
- CAM – Computer-aided manufacturing
- CFD – Computational fluid dynamics
- CNC – Computer numerical control