Not having used any collets at all previously and there being precious little information that I could find on how to use this lever-operated collet closer, I thought I'd document how it works.
This is on a South Bend 10K and as far as I know is original to my machine (despite the mis-matched paint--I didn't repaint the closer when I did the lathe).
First, here are the 4 main parts of the system. A collet (type 6K), a thing some people refer to as a spindle thread protector but is actually part of the collet system, a pin wrench and the closer lever assembly itself.
And here's the outside end of the headstock on my lathe where the closer attaches. The important parts are the back of the headstock bore and the pin in the upper left, just to the right of the back gear handle.
Step 1: Remove the mounting bracket from the lever assembly.
Step 2: Put the mounting brack on the pin just forward of the back gear lever. I did this with the gear cover open and should also have done it with the headstock spindle cover open, because you can't open either with the collet closer in place. The gear cover isn't a big deal, but changing speeds on the pulleys with the closer in place is a hassle. (It's possible my spindle cover isn't original and maybe the original would have opened.)
Step 3: Now put the closer through the headstock bore and bolt the bracket back on.
Step 4: The "spindle thread protector" goes on with the wrench.
Note that this ring really does protect the spindle threads, which could easily be in danger when operating with a collet. However, another purpose is to pop this little pin through
which engages with the slot on the collet
which keeps it from spinning while you engage the collet threads.
Step 5: Screw a collet in to engage it with the threads on the end of the closer. Don't necessarily screw it on all the way. For now, "a ways" is fine. When you have some work in there, you'll need to adjust it so the lever handle "pops" from the released position
to the locked position.
That will require some adjustment depending on the exact diameter of your work relative to the collet.