I've been lurking here for a while and had to tell you all how I made circular needles. I'm not talking DPN. I made short dowel needles sanded down a dowel, skewer or chopstick, cut it to about 4". I drilled up the end carefully to receive a piece of 2mm round leather cording. taper the second end but not to a point, just enough to keep the stitches from catching. Glue a piece of round leather cording into the end with strong glue .
Another finishing tip: I couldn't get enough wax from the wax paper method so I dipped it into a melted candle. Then to scrape the excess off I just ran it through the appropriate hole of my needle sizer and the extra wax just fell off. It made them nice and smooth and they smell like apple/cinnamon! If you're going to work with white yarn first you may want to not use a colored candle!
I've made several pair of circular needles from shish-kebob skewers (size
varying the leather cording length to make 16-29" One pack of the bigger skewers will make more than one knitter will need. The smaller skewers make great sock needles (size 3). 1/2" dowel makes a nice size 10. When I wanted to sit down to make needles I wasn't feeling like also working with clay so I just got a bag of various sized wooden beads and glued them on the ends.
For my needle keepers I just use a cork on the end. Cut it in half so it's not unwieldy. It already has a hole from the corkscrew so it just sticks right on or you can drill it out to fit better.
Hope these ideas are helpful to someone, let me know if they are