SUPERLOK Tube Fittings shall be delivered to the customer completely assembled and ready for installation.

– Turning the nut to the finger tight position is the only requirement before starting the installation.
– Fittings should not be disassembled before installation to maintain cleanliness and prevent unwanted foreign
   material from entering the system.
– Care in the proper selection of tubing also contributes to a safe and reliable installation.

Step 1
Insert the tubing into the SUPERLOK Tube Fitting making sure the tubing is bottomed out and is in complete contact with the shoulder of the fitting. Also, the nut should be in the finger-tight position at this time.

Step 2
Before tightening, mark the SUPERLOK nut at the 6
o’clock position.

Step 3
Hold the fitting body safely with a back-up wrench and tighten the nut 1-1/4 turns until your mark reaches the 
9 o’clock position.

Note: For 1/16”, 1/8”and 3/16 inch; 2, 3 and 4 mm tube fittings,tighten the nut 3/4 of a turn to the 3 o’clock position.


On initial installation, the SUPERLOK Inspection Gauge assures the installer or inspector that a fitting has been sufficiently tightened.

Position the SUPERLOK Inspection Gauge next to the gap between the nut and the body.

If the gauge will not enter the gap, the fitting is sufficiently Tightened.
If the gauge will enter the gap, additional tightening is required.


Since tubing has different O.D. tolerances, it is important to have a common starting point to take out in dimensional variations. This is done by tightening the fitting slightly until the tubing can not freely rotate in the fitting as it can in the finger-tight position. At this point tighten the nut 1-1/4 turns.

Safety Considerations on Installations for High Pressure System

Make sure the proper tubing wall thickness is selected in accordance with pressure ratings.
(Tubing should have a hardness of HRB 80 or less)

Do not assemble or disassemble fittings when the sytem is pressurized.


Step 1

Pic.1 shows the fitting in the disconnected position. Insert the tubing with the pre-swaged ferrules into the fitting body making sure the front ferrule is firmly seated as shown in Pic. 2

Step 2

Finger-tighten the nut and then with a wrench turn the nut to the original 9 o’clock position. At this point a slight change of resistance will be felt. Tighten the not slightly more as the change in resistance is felt and the installation is complete as shown in Pic. 3 by tightening slightly more.