Collets are a sleeve that uses pressure and friction to hold something in place. They’re used in TIG welding, on mills and on lathes, among other uses.
First, Kevin shows a TIG welding collet. It has two slits in its sides and is hollow, with a shoulder on one end. It holds the TIG tungsten. A collet body slips over the collet. When you put an endcap on the torch, it presses against the collet and shoves it inside the collet body and into the tapered end, which causes it to hold onto the tungsten.
Next, Kevin shows some mill collets. They’re quite a bit larger than the TIG welding collets. The slots – there are three of them on this collet – are a lot easier to see. You slip an end mill into the hole in the middle of the collet. Then you thread the quill, or drawbar, down through the mill and draw the collet up inside. That squeezes the collet to capture the end mill. He shows how it fits up into the mill and tightens the drawbar to secure it.
Kevin also uses a collet on his lathe. It’s very similar to the mill collets. It fits into a tapered hole on the lathe, the work piece slides into a hole on the end, and then it has threads on the other end that tighten it down. He slips the collet into the end of the lathe, then shows the threaded bar that he puts into the end of the lathe to meet up with the collet and tighten it to suck the collet in and pinch it.
Why use a collet instead of a chuck on a lathe? A chuck, whether it’s a three-jaw, four-jaw or the six-jaw Kevin has, is only going to hold your work on those points. With a collet, you are grabbing the whole thing. That holds your work more securely, reduces the chance of it spinning and getting grrr marks on it if it happened to spin inside the chuck.
What do collets cost? TIG collets are about $1.50 each depending upon what size you get. You can get them at your local welding store or online. The mill and lathe collets usually range from $15 – 30. You can get them at MCSdirect.com
Do you need collets? Yes, certainly when you’re talking about TIG welding. Those collets need to be the same size as your tungsten. In fact, all three pieces need to be the same size to work together correctly. With the mill, you can use tool holders instead of collets. Tool holders fit into the same place as a collet and are secured by the same drawbar, but they have a straight hole inside that lines up with a flat spot on the end mill that lets you tighten up a set screw so you can get to work.
On the lathe, a collet works better to hold smaller metal stock and reduces the chance for grrr marks. Your work won’t spin in a collet!
Kevin is ready to go back to work, but you might want to hang around a little big longer and see him do something he’s done hundreds of times – but not on camera …..