| Tube O.D. | Pipe O.D. | Metric | Male Thread O.D. | Female Thread I.D. | ||||
| MM | (In.) | MM | (In.) | Thread Size | MM | Frac. | MM | Frac. |
| 14 | .55 | 13.25 | .52 | M20 x 1.5 | 20 | 25/32 | 18.5 | 23/32 |
| 16 | .63 | 16.75 | .66 | M24 x 1.5 | 24 | 15/16 | 22.5 | 7/8 |
| 22 | .87 | 21.25 | .83 | M30 x 1.5 | 30 | 1 3/16 | 28.5 | 1 1/8 |
| 28 | 1.10 | 26.75 | 1.05 | M36 x 1.5 | 36 | 1 13/32 | 34.5 | 1 11/32 |
| 35 | 1.38 | 33.50 | 1.32 | M45 x 1.5 | 45 | 1 3/4 | 43.5 | 1 23/32 |
| 40 | 1.57 | 42.25 | 1.66 | M52 x 1.5 | 52 | 2 1/32 | 50.5 | 2 |
| The threads retain the connection. | ||||||||