Gib Head key is used for coupling a pulley with shaft.

Brazing is essentially similar to soldering but it gives a much stronger joint than soldering. The principal differences is the use of a harder filler material, commercially known as spelter which fuses at some temperature above red heat, but below the melting temperature of the parts to be joined.

In Brazing most commonly used flux is “Borax” for ferrous and non-ferrous metals. It removes rust and prevents atmospheric effect, when brazing operation is going on