How many bolts does a 250A JIS 10K flange have?

12, of M22, through holes of 25 mm (0.98 in) on a 355 mm (13.98 in) bolt circle.

What is the bolt circle of a 250A JIS 10K flange?

355 mm (13.98 in). The holes are 30° apart, and the first one sits 15° off the centre line, so that two flanges mate in any symmetric position. The chord between neighbouring holes is 91.9 mm (3.62 in).

Can a 250A JIS 10K 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. For pressure service, the flange takes the material, thickness and facing that JIS B 2220 sets for its class.

In what order are the bolts of a 250A JIS 10K flange tightened?

In a cross pattern, with the holes numbered round the flange: 1, 7, 4, 10, 2, 8, 5, 11, 3, 9, 6, 12. In at least three passes, raising the torque each time, and then round in order until no nut turns.

250A JIS 10K flange: dimensions, bolt circle and drilling (JIS B 2220)

The 250A JIS 10K flange to JIS B 2220 is 400 mm (15.75 in) across, with 12 holes of 25 mm (0.98 in) on a 355 mm (13.98 in) bolt circle, for M22 bolts; the pipe is 267.4 mm (10.53 in) outside. The holes straddle the centre lines, the first one 15° off, and the chord between neighbouring holes, which is the divider setting for stepping the drilling out, is 91.9 mm (3.62 in).

The 250A JIS 10K flange as the calculator draws it: the outline, the bore at the pipe outside diameter and the 12 holes.

Download the 1:1 drilling template (free PDF) Open in the generator: DXF for plasma and laser

On A4 or Letter sheets to tape together, with a check ruler on every sheet: print at actual size, 100 %. No account needed.

Dimensions

Outside diameter	400 mm (15.75 in)
Flange thickness (t)	24 mm (0.94 in)
Bolt circle (PCD)	355 mm (13.98 in)
Number of holes	12
Hole diameter	25 mm (0.98 in)
Bolts	M22
Pipe outside diameter	267.4 mm (10.53 in)
Angle between holes	30°
First hole from the centre line	15°
Chord between neighbouring holes	91.9 mm (3.62 in)

The thickness of the steel flange in JIS B 2220; cast iron flanges are thicker. The bolts are metric, M22, and their length depends on the gasket and the type of flange.

Hole coordinates

From the centre of the flange, in mm, with the first hole 15° off the horizontal axis and the others counter-clockwise, as the standards lay the drilling out.

Hole	Angle	x (mm)	y (mm)
1	15°	171.0	45.8
2	45°	125.2	125.2
3	75°	45.8	171.0
4	105°	-45.8	171.0
5	135°	-125.2	125.2
6	165°	-171.0	45.8
7	195°	-171.0	-45.8
8	225°	-125.2	-125.2
9	255°	-45.8	-171.0
10	285°	45.8	-171.0
11	315°	125.2	-125.2
12	345°	171.0	-45.8

Bolt tightening order

1 – 7 – 4 – 10 → 2 – 8 – 5 – 11 → 3 – 9 – 6 – 12

The cross pattern of ASME PCC-1, with the holes numbered as in the table above, so that the gasket is pulled down evenly. Go round in at least three passes, raising the torque each time (about 30 %, 60 % and 100 %), then go round in order until no nut turns. The torque itself depends on the bolt, the gasket and the lubricant: it comes from the gasket or bolt supplier.

Questions

How many bolts does a 250A JIS 10K flange have?: 12, of M22, through holes of 25 mm (0.98 in) on a 355 mm (13.98 in) bolt circle.
What is the bolt circle of a 250A JIS 10K flange?: 355 mm (13.98 in). The holes are 30° apart, and the first one sits 15° off the centre line, so that two flanges mate in any symmetric position. The chord between neighbouring holes is 91.9 mm (3.62 in).
Can a 250A JIS 10K 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. For pressure service, the flange takes the material, thickness and facing that JIS B 2220 sets for its class.
In what order are the bolts of a 250A JIS 10K flange tightened?: In a cross pattern, with the holes numbered round the flange: 1, 7, 4, 10, 2, 8, 5, 11, 3, 9, 6, 12. In at least three passes, raising the torque each time, and then round in order until no nut turns.

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