Datasheet

Connection thread size
(R, NPT)
1/16, 1/8
1/4
3/8
1/2
7 to 9
12 to 14
22 to 24
28 to 30
Proper tightening torque
[N·m]
Fittings & Tubing
Precautions 3
Be sure to read this before handling.
Maintenance Tightening the threaded portion of the connection thread
Caution
1. Installation and removal of tubing for One-touch
fittings
1) Installation of tubing
(1) Cut the tubing perpendicularly, being careful not to damage
the outside surface. Use an SMC tube cutter “TK-1”, “TK-2”
or “TK-3”. Do not cut the tubing with pliers, nippers,
scissors, etc., otherwise, the tubing will be deformed and
trouble may result.
(2) The outside diameter of the polyurethane tubing swells when
internal pressure is applied to it. Therefore, it may be possible
that the tubing cannot be re-inserted into the One-touch
fitting. Check the tubing outside diameter, and when the
accuracy of the outside diameter is +0.07 mm or larger for ø2,
+0.15 mm or larger for other sizes, insert into the One-touch
fitting again, without cutting the tubing to use it. When the
tubing is re-inserted into the One-touch fitting, confirm that
the tubing goes through the release button smoothly.
(3) Grasp the tubing, slowly push it into the One-touch fitting
until it comes to a stop.
(4) Pull the tubing back gently to make sure it has a positive
seal. Insufficient installation may cause air to leak or the
tubing to release.
2) Removal of tubing
(1) Push the release button flange evenly and sufficiently to
release the tube.
(2) Pull out the tubing while keeping the release button
depressed. If the release button is not held down
sufficiently, the tubing cannot be withdrawn.
(3) To reuse the tubing, remove the previously lodged portion
of the tubing. If the lodged portion is left on without being
removed, it may result in air leakage and removal of the
tubing difficult.
2. Connecting products with metal rods
Fittings with metal rod (Series KC and old Series KQ/KQ2)
cannot be connected to One-touch fittings.
3. When mounting tubing, resin plugs, metal rods, etc.,
do not press the release button before mounting.
Also, do not press the release button before mounting. This
may result in detachment.
Mounting/Piping
One-touch Fittings
Caution
1. Be certain to wear safety glasses at all times during
periodical inspections.
2. Replace fittings or tubing having the following
problems.
1) Cracks, gouges, wearing, corrosion
2) Air leakage
3) Twists or crushing of tubing
4) Hardening, deterioration, softening of tubing
3. When replacing tubes or fittings, do not try to mend
or repair and then reuse them.
1. Connection thread: M3
First, tighten it by hand, then give it an additional 1/4 turn with a
wrench.
A reference value for the tightening torque is 0.4 to 0.5 N·m.
2. Connection thread: M5, M6 and 10-32UNF
First, tighten it by hand, then give it an additional 1/6 turn to 1/4
turn with a wrench.
A reference value for the tightening torque is 1 to 1.5 N·m.
3. M6
First, tighten it by hand, then give it an additional 1/6 turn to 1/4
turn with a wrench.
Note) Excessive tightening may damage the thread portion or
deform the gasket and cause air leakage.
If the screw is too shallowly screwed in, it may come
loose or air may leak.
4. Fittings with sealant: R, NPT
1. The proper tightening torques of the fittings are as shown in
the table below. As a guide, tighten by hand, then turn it two
or three turns with a wrench.
2. If the fitting is tightened with excessive torque, a large
amount of sealant will seep out. Remove the excess sealant.
3. Insufficient tightening may loosen the threads, or cause air
leakage.
4. Reuse
1) Normally, fittings with a sealant can be reused 2 to 3
times.
2) To prevent air leakage through the sealant, remove any
loose sealant stuck to the fitting by blowing air over the
threaded portion.
3) If the sealant no longer provides effective sealing, wrap
sealing tape over the sealant before reusing. Do not use
the sealant in any form other than a tape type.
4) Once the fitting has been tightened, backing it out to its
original position often causes the sealant to become
defective. Air leakage will occur.
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