How many bolts does a 20A JIS 10K flange have?

4, of M12, through holes of 15 mm (0.59 in) on a 75 mm (2.95 in) bolt circle.

What is the bolt circle of a 20A JIS 10K flange?

75 mm (2.95 in). The holes are 90° apart, and the first one sits 45° off the centre line, so that two flanges mate in any symmetric position. The chord between neighbouring holes is 53 mm (2.09 in).

Can a 20A 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 20A JIS 10K flange tightened?

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

20A JIS 10K flange: dimensions, bolt circle and drilling (JIS B 2220)

The 20A JIS 10K flange to JIS B 2220 is 100 mm (3.94 in) across, with 4 holes of 15 mm (0.59 in) on a 75 mm (2.95 in) bolt circle, for M12 bolts; the pipe is 27.2 mm (1.07 in) outside. The holes straddle the centre lines, the first one 45° off, and the chord between neighbouring holes, which is the divider setting for stepping the drilling out, is 53 mm (2.09 in).

The 20A JIS 10K flange as the calculator draws it: the outline, the bore at the pipe outside diameter and the 4 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	100 mm (3.94 in)
Flange thickness (t)	14 mm (0.55 in)
Bolt circle (PCD)	75 mm (2.95 in)
Number of holes	4
Hole diameter	15 mm (0.59 in)
Bolts	M12
Pipe outside diameter	27.2 mm (1.07 in)
Angle between holes	90°
First hole from the centre line	45°
Chord between neighbouring holes	53 mm (2.09 in)

The thickness of the steel flange in JIS B 2220; cast iron flanges are thicker. The bolts are metric, M12, 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 45° off the horizontal axis and the others counter-clockwise, as the standards lay the drilling out.

Hole	Angle	x (mm)	y (mm)
1	45°	26.2	26.2
2	135°	-26.2	26.2
3	225°	-26.2	-26.2
4	315°	26.2	-26.2

Bolt tightening order

1 – 3 – 2 – 4

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 20A JIS 10K flange have?: 4, of M12, through holes of 15 mm (0.59 in) on a 75 mm (2.95 in) bolt circle.
What is the bolt circle of a 20A JIS 10K flange?: 75 mm (2.95 in). The holes are 90° apart, and the first one sits 45° off the centre line, so that two flanges mate in any symmetric position. The chord between neighbouring holes is 53 mm (2.09 in).
Can a 20A 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 20A JIS 10K flange tightened?: In a cross pattern, with the holes numbered round the flange: 1, 3, 2, 4. In at least three passes, raising the torque each time, and then round in order until no nut turns.

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