S and S Machine
Bicycle Torque Couplings (BTCs)
Your Travel Bike........Your Only Bike!

Chrome-moly TIG weldable BTCs

No zinc plating in the area near the weld.

The lug is pressed into the tube then the lug and tube are TIG welded together.
Where there is zinc plating, the lug doesn't get discolored.

The second groove on the rubber seal fits over the lug ridge as shown here in red. 
(the seal is temporarily turned inside out for this photo)

Once in place, the seal fits tight against the lug and tube and it conceals the weld.

When the nut is tight and the seal is properly positioned, there is no gap between the seal and nut.

When the nut is pulled back against the seal, the nut should partially cover the groove.
The seal acts as a stop to prevent the nut from damaging the painted tube.

Before installing the lug into the tube

After welding the lug into the tube.

The seal fits tight against the back of the threads
The seal can be replaced by stretching it enough to fit over the threads.