I am trying to redesign a cardigan, and wish to add a shawl collar. I want to knit it on. how would I do that?
"Hartland" by Rowan (you can look it up on Ravelry) has a shawl collar. It was not the easiest thing in the world to do. It was not knitted on, but knitted separately then sewn on. Hope this helps. Good Luck.
I have knit them but have not designed them. So you will have to do a little bit of math to finish up your particular garment. You would want to have a cardigan that has a long "V" in the front, not the kind that comes up close to your chin, clearly. The ones I have knit start out with 1-2 rows on all the picked-up stitches and then gradually begin decreasing the stitches on either end. Knit until the collar is the desired depth and width and then bind off.
For the math, you will have to know how many stitches you are picking up, your knitting gauge and how deep you want the collar to be. Say you pick up 100 stitches and you knit 4 rows to the inch and you want your collar to be 6 inches deep. Your 6-inch portion of the collar will need 24 rows. Also say that you pick up 100 stitches and you knit 5 stitches to inch. Your total collar will be 20 inches long. If you want the middle third of it to be the full shawl portion, that would mean that 33 stitches will be the full depth. So you need to decrease 33 stitches on each side (okay, well one side or the middle will have to have one extra stitch) in 24 rows. So a few rows of decreasing 2 stitches and then the rest in decreasing 1 stitch.