Together they determine whether the arc is stable and whether the gas actually covers the puddle.
Standard collets grip the electrode at the top of the torch head. Gas lens collets change the internal geometry to work with a lens body, which needs a longer collet than a standard setup. Collets are size-specific to the electrode diameter — a 3/32 collet will not grip 1/16 tungsten, and forcing it damages both the collet and the electrode.
A gas lens is a stack of fine screens that straightens the gas flow. The result is better coverage at longer stick-out, less turbulence, less gas waste, and better visibility of the puddle because the cup can be larger without needing more flow. Gas lenses are the standard for stainless and titanium work where any air entrainment causes discolouration or porosity.
Collet bodies hold the collet and thread into the torch head. They are series-specific — a 9 series body will not fit a 17 series torch — and the gas lens version is longer than the standard version. Worn or cross-threaded collet bodies cause poor gas coverage and erratic current transfer.
