Steel take-off per 45 degree elbow
Take-off here is the center to end dimension of an ASME B16.9 long radius 45 degree elbow, measured to the weld end.
| Pipe size | Take-off (in) | Decimal |
|---|---|---|
| 1" | 7/8 | 0.875 |
| 1 1/4" | 1 | 1.000 |
| 1 1/2" | 1 1/8 | 1.125 |
| 2" | 1 3/8 | 1.375 |
| 2 1/2" | 1 3/4 | 1.750 |
| 3" | 2 | 2.000 |
| 4" | 2 1/2 | 2.500 |
| 6" | 3 3/4 | 3.750 |
Source
The two tables agree.
Worked example
Rise 12 inches, roll 9 inches, 2 inch steel. Travel is 21 3/16". Take-off is 1 3/8 inch per elbow. Cut length = 21.21 - 2 x 1.375 = 18.46 inches, about 18 7/16".
Root gap and other angles
A butt weld needs a root gap, often about 1/8 inch per joint. The tool does not include it in the cut length, so subtract it yourself. Steel at an angle other than 45 degrees is scaled from the 45 degree value. Treat that result as approximate and check it against your fitting.
Questions
What is the take-off of a 2 inch steel 45 degree long radius elbow?
1 3/8 inch (1.375), center to end, from ASME B16.9 dimension tables.
Do I subtract the weld gap?
Yes, if your procedure leaves a gap. The tool shows the cut length without it.