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.

DN 65 PN 16 flange: dimensions, bolt circle and drilling (EN 1092-1)

The DN 65 PN 16 flange to EN 1092-1 is 185 mm (7.28 in) across, with 8 holes of 18 mm (0.71 in) on a 145 mm (5.71 in) bolt circle, for M16 bolts; the pipe is 76.1 mm (3 in) outside. The holes straddle the centre lines, the first one 22.5° off, and the chord between neighbouring holes, which is the divider setting for stepping the drilling out, is 55.5 mm (2.18 in).

The DN 65 PN 16 flange as the calculator draws it: the outline, the bore at the pipe outside diameter and the 8 holes.

Dimensions

Outside diameter	185 mm (7.28 in)
Bolt circle (PCD)	145 mm (5.71 in)
Number of holes	8
Hole diameter	18 mm (0.71 in)
Bolts	M16
Pipe outside diameter	76.1 mm (3 in)
Angle between holes	45°
First hole from the centre line	22.5°
Chord between neighbouring holes	55.5 mm (2.18 in)

Draw this flange: 1:1 template and DXF

Hole coordinates

From the centre of the flange, in in, with the first hole 22.5° off the horizontal axis and the others counter-clockwise, as the standards lay the drilling out.

Hole	Angle	x (in)	y (in)
1	22.5°	2-5/8"	1-1/16"
2	67.5°	1-1/16"	2-5/8"
3	112.5°	-1-1/16"	2-5/8"
4	157.5°	-2-5/8"	1-1/16"
5	202.5°	-2-5/8"	-1-1/16"
6	247.5°	-1-1/16"	-2-5/8"
7	292.5°	1-1/16"	-2-5/8"
8	337.5°	2-5/8"	-1-1/16"

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.