The name Edison thread for the socket of lamps traces back to Thomas Alva Edison.
| Thread Size | Major Diameter | Tapping | Pitch |
| mm | Drill Size | mm | |
| mm | |||
| E 5.5 | 5.5 | 4.9 | 1.00 |
| E 10 | 10 | 8.8 | 1.81 |
| E 14 | 14 | 12.5 | 2.82 |
| E 16 | 16 | 14.7 | 2.50 |
| E 18 | 18 | 17.0 | 3.00 |
| E 27 | 27 | 24.5 | 3.62 |
| E 33 | 33 | 30.8 | 4.23 |
| E 40 | 40 | 36.3 | 6.35 |