16 inch class 300 flange: dimensions, bolt circle and drilling (ASME B16.5)
The 16 inch class 300 flange to ASME B16.5 is 25.5 in (647.7 mm) across, with 20 holes of 1.38 in (34.9 mm) on a 22.5 in (571.5 mm) bolt circle, for 1-1/4 in bolts; the pipe is 16 in (406.4 mm) outside. The holes straddle the centre lines, the first one 9° off, and the chord between neighbouring holes, which is the divider setting for stepping the drilling out, is 3.52 in (89.4 mm).
Dimensions
| Outside diameter | 25.5 in (647.7 mm) |
|---|---|
| Bolt circle (PCD) | 22.5 in (571.5 mm) |
| Number of holes | 20 |
| Hole diameter | 1.38 in (34.9 mm) |
| Bolts | 1-1/4 in |
| Pipe outside diameter | 16 in (406.4 mm) |
| Angle between holes | 18° |
| First hole from the centre line | 9° |
| Chord between neighbouring holes | 3.52 in (89.4 mm) |
Draw this flange: 1:1 template and DXF
Hole coordinates
From the centre of the flange, in mm, with the first hole 9° off the horizontal axis and the others counter-clockwise, as the standards lay the drilling out.
| Hole | Angle | x (mm) | y (mm) |
|---|---|---|---|
| 1 | 9° | 282.2 | 44.7 |
| 2 | 27° | 254.6 | 129.7 |
| 3 | 45° | 202.1 | 202.1 |
| 4 | 63° | 129.7 | 254.6 |
| 5 | 81° | 44.7 | 282.2 |
| 6 | 99° | -44.7 | 282.2 |
| 7 | 117° | -129.7 | 254.6 |
| 8 | 135° | -202.1 | 202.1 |
| 9 | 153° | -254.6 | 129.7 |
| 10 | 171° | -282.2 | 44.7 |
| 11 | 189° | -282.2 | -44.7 |
| 12 | 207° | -254.6 | -129.7 |
| 13 | 225° | -202.1 | -202.1 |
| 14 | 243° | -129.7 | -254.6 |
| 15 | 261° | -44.7 | -282.2 |
| 16 | 279° | 44.7 | -282.2 |
| 17 | 297° | 129.7 | -254.6 |
| 18 | 315° | 202.1 | -202.1 |
| 19 | 333° | 254.6 | -129.7 |
| 20 | 351° | 282.2 | -44.7 |
Questions
- How many bolts does a %{size} %{class} flange have?
- %{holes}, of %{bolt}, through holes of %{hole} on a %{circle} bolt circle.
- What is the bolt circle of a %{size} %{class} flange?
- %{circle}. The holes are %{angle}° apart, and the first one sits %{half}° off the centre line, so that two flanges mate in any symmetric position. The chord between neighbouring holes is %{chord}.
- Can a %{size} %{class} flange be cut from plate?
- As a plate flange, for low pressure: ducts, tanks, water lines. The outline and the drilling above are what the flange calculator draws, with the 1:1 template and the DXF for plasma or laser. A pressure flange to %{standard} is forged, with a hub and a raised face, and its thickness and facing come from the standard.