What end of a fitting should the tube or male end be inserted into when using sockets and fittings?

In the context of using sockets and fittings in soldering and brazing applications, inserting the tube or male end into the shoulder of the cup is essential for achieving a proper seal and ensuring a strong joint. The shoulder of the cup is specifically designed to support and align the fitting correctly, creating a robust junction that can withstand the stresses and pressures encountered in plumbing or other piping systems.

Inserting the tube into the shoulder allows for uniform spacing around the joint, leading to an even distribution of heat during the soldering or brazing process. This uniform heat helps to melt the filler material effectively, allowing it to flow into the joint and form a reliable bond. It also helps prevent misalignment and potential leaks during operation.

In contrast, inserting the tube at the end of the tube or base of the fitting could lead to improper alignment and ineffective soldering, while inserting at the center of the socket might not provide the necessary support for a secure fit. Therefore, the shoulder of the cup is the correct choice, ensuring both the integrity of the connection and the effectiveness of the soldered joint.