How to Calculate Screw Thread Converter
What is Screw Thread Converter?
Screw thread converters translate between different thread designations: UNC, UNF, metric (M), BSW, etc.
Formula
Inch: #10-24 UNC = 10 size, 24 threads/inch
- UNC
- 10 size — 10 size
Step-by-Step Guide
- 1Metric: M10 = 10 mm diameter, coarse (1.5 mm pitch) or fine (1.25 mm)
- 2Inch: #10-24 UNC = 10 size, 24 threads/inch
- 3Non-interchangeable between systems (need washers, adapters)
Worked Examples
Input
M8 metric thread
Result
8 mm diameter, UNC equivalent #5-40, similar size
Not exactly interchangeable
Common Mistakes to Avoid
- ✕Assuming metric and inch are compatible (they're not)
- ✕Not checking thread pitch (critical for alignment)
Frequently Asked Questions
Can metric and inch threads be used interchangeably?
No, slightly different pitch and angle. Using wrong thread can damage equipment.
What's the difference between coarse and fine pitch?
Fine pitch holds tighter, suits thin walls, vibration-resistant. Coarse easier to assemble, stronger.
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