My logic is failing me. You must use them as regular straight needles and turn for each row, otherwise it is a tube?? Is it because there are so many stitches cast on??
Kitty, you're right - you knit back & forth on them like you would with straight needles.
For me, it seems to help distribute the weight more evenly when you're near the beginning or end of the rows.
Also, I have a cat who likes to help me knit, and it's much easier if there isn't a straight needle end waving around in front of her! LOL
Yes, you knit as you would with strait needles. I use circs for almost everything I knit. No long needle ends to get in the way or caught on chair arms. Also, the cable on the circs help hold the weight of the afghan, instead of all of it being in your hands as you knit the afghan.
I can't imagine knitting an afghan on just plain straight needles...there wouldn't be nearly enough room on it for a whole afghan. I've knitted throws, single and double sized blankets and I use my Denise needles...for the bigger ones I may use all the extensions and make it as big as I can. I'd think the only way to use a plain old straight needle would be to knit the afghan or blanket in strips, from top to bottom, and then sew them together.
Once I started using circular needles I never went back to straight. That is, except for socks. Then I use a set of 5 needles.
The weight of your work is in your lap, instead of pulling at the end of the needles.