SMC Networks KQ2 Series, Instruction Manual

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Counterbore diameter ø

D3

Seal bearing surface diameter ø

D2

Rz 25

(Sealing face)

Chamfer dimension

ø

D1

Female thread

inclination angle: 

1  or less

Thread

Proper thickness

Proper
coating 
range

Non-coating
range

With sealant

For Pneumatic Piping/Fittings & Tubing

Prior to Use

Fittings with Sealant

Seal material (fluororesin) is coated on the thread part with the proper thickness and range, that reduces the piping work, such as coating the seal 
on the thread.

Female Thread Conditions Applicable to Face Seal

1. Surface roughness of bearing surface: Rz 25 or less
2. Chamfer dimension: ø

D1

, Seal bearing surface diameter: ø

D2

 (Refer to the table below.)

3. Female thread inclination angle: 1  or less
4. Counterbore diameter when the female thread is counterbored.: ø

D3

· Models with width across flats: Body width across flats x 1.1 or more
· Models other than hexagon (Hexagon socket head male connector etc.): Body dime 0.2 mm or more

  The width across flats and the body dimensions differ depending on the model even when the same thread size is used. 

Refer to the dimensions in the catalog.

5. If oil content or sealant is sticking to the female thread, this may cause damage of the product. Remove it before piping.

Table 1

Precautions

For products that do not satisfy the female thread conditions shown above and the piping with a piping pitch narrower than the product dimension, 
use the current sealant type.

  The rubber parts of the face seal cannot be replaced.
  The rubber parts of the face seal may fall off by the air blow and they cannot be mounted again. Be careful not to perform the air blow.

Connection 

thread size

Chamfer dimension

ø

D1

 [mm]

Seal bearing surface diameter 

ø

D2

 [mm]

R1/8

10.2 to 10.4

12 or more

R1/4

13.6 to 13.8

17 or more

R3/8

17.1 to 17.3

21 or more

R1/2

21.4 to 21.6

27 or more

NPT1/16

8.2 to 8.4

11.11 or more

NPT1/8

10.5 to 10.7

12.7 or more

NPT1/4

14.1 to 14.3

17.46 or more

NPT3/8

17.4 to 17.6

22 or more

NPT1/2

21.7 to 21.9

28.7 or more

G1/8

10.2 to 10.6

12 or more

G1/4

13.6 to 14.0

17 or more

G3/8

17.1 to 17.5

21 or more

G1/2

21.4 to 21.8

27 or more

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