Back capThe back cap: a plastic cap screwed on the top. It covers the back of the tungsten electrode, stops gas escaping from the top, and tightening it locks the electrode in the collet.
Torch bodyThe part everything screws into. It is covered in heat-resistant, insulating plastic. Also called the head.
ColletA slit copper sleeve that grips the tungsten electrode. It grips when the back cap is tightened. Collets are sized to the electrode.
Tungsten electrodeThe tungsten electrode: the rod the arc jumps from. It is not melted into the weld, unlike the filler rod.
Gas nozzleDirects the shielding gas over the weld pool. Usually ceramic. Also called the cup.
Other 3
HandleMade of plastic so the welder is insulated from the torch.
HosesThe hoses and cable supply the torch. They bring shielding gas, cooling water (on water-cooled torches) and welding current.
Gas orifice nutScrews into the torch body round the collet. Holes in it let the shielding gas out. Also called the collet body.
How this list was compiled: Read 2026-09-28. (1) Wikipedia, Gas tungsten arc welding, https://en.wikipedia.org/wiki/Gas_tungsten_arc_welding : the manual torch has a handle; torches connect by cables to the power supply and hoses to the shielding gas and, where used, water; internal metal parts are copper or brass; the tungsten electrode is held in the centre by a collet sized to its diameter, with ports round it for the shielding gas; the torch body is heat-resistant insulating plastic; the gas nozzle is alumina or ceramic (or fused quartz), and gas lenses can be fitted; the electrode is non-consumable. (2) US Army, Welding Theory and Application (TC 9-237), torch nomenclature, https://archive.org/details/micro_IA41152616_0592 : cap (plastic; shields the electrode, stops gas escaping from the top, locks the electrode in place), collet (copper; squeezes the electrode when the cap is tightened), gas orifice nut (lets the gas out), gas nozzle (ceramic for light duty, water-cooled copper for heavy), torch handle (plastic), hoses (water, gas and the power cable inside the water drain line). Licence: own work
The drawing: Drawn for this site by script, 2026-09-28. Own work, nothing traced. Licence: own work
How it works
These are the parts of a TIG torch, pulled apart along the line they share so each one shows, in the order they fit together. Start with the 5 main parts.
Read the full guide
Holding the tungsten
The tungsten electrode slides through the collet, a slit copper sleeve inside the torch body. Tightening the back cap on top squeezes the collet and locks the electrode in place.
Shielding the weld
The gas orifice nut screws in round the collet, and shielding gas flows out through its holes. The ceramic gas nozzle, or cup, screws on over it and directs the gas over the weld. Hoses bring gas, power and sometimes cooling water through the handle.
Match the collet to the electrode: collets come in sizes for each tungsten diameter, and the wrong one will not grip.
Questions and answers
What does the collet do in a TIG torch?
It holds the tungsten electrode in the centre of the torch. When the back cap is tightened, the slit copper collet squeezes the electrode and locks it in place.
What is the cup on a TIG torch?
The gas nozzle, usually ceramic. It directs the shielding gas over the weld so the air cannot reach the hot metal. Bigger cups cover a wider area.
Is the tungsten electrode melted into the weld?
No. The tungsten carries the arc but is not consumed. Metal is added, when needed, from a separate filler rod.