A collet holds the Tungsten electrode. When you screw on the back cap, it pushes the collet against the gas nozzle, which squeezes the collet jaws. This makes a good electrical contact, holds the Tungsten electrode in place and prevents the Tungsten electrode from moving. To adjust the Tungsten electrode, you loosen the back cap, move the Tungsten electrode. when adjustment is complete, re-tighten the back cap.
The ‘Standard’ collet is the longer collet that fits a bog stand gas lens.
A ‘Stubby’ collet is a shorter collet that fits the shorter stubby gas lens, or the wide gas lens (that often have a diffuser fitted).
A ‘Wedge’ collet has an angled end and no slots down the side of the collet. A fault with slotted collets is that they can become twisted and deformed if overtightened. The wedge collet overcomes this issue.
How do they work? – The offset chamfer forces the collet to one side when screwing in the back cap, thereby wedging the Tungsten electrode in place. The Tungsten electrode may need a little push to get it to release when removing. Because there are no slots in a ‘Wedge’ collet, they last longer.
A ‘Reverse’ collet is much shorter, with the clamping slots on the opposite end.
How do they work? – They are wider than the other collets, so they sit on the back of the gas lens, rather than sliding all the way inside the gas lens body. They are slotted on the opposite end, so that the back cap squeezes the slots clamping the Tungsten electrode, (rather than the back cap pushing the collet into the gas lens).
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