Nominal Diameter
The nominal diameter is the diameter specified as the standard dimension for a thread – for metric threads, "M8" means a nominal diameter of 8 mm.
Significance:
- Decisive for the selection of nuts, bolts, thread inserts, etc.
- Not always equal to the minor or outer diameter – these are often larger or smaller.
Practical example:
For an M10 thread insert, "M10" is the nominal diameter – the matching screw, nut, etc. also has a nominal diameter of 10 mm.