I was really nervous about doing an afterthought pocket, to be honest. The idea of snipping my knitting, quite frankly, makes me want to vomit. But when you need a pocket, you need a pocket. I am not sure if what I did was "right" perse; but, when all was said and done there were a pair of pockets on a sweater that were pocketless at the beginning of my pocket-making journey.
After all was said and done, doing afterthought pockets are kind of easy. You just need to get past the whole fear of cutting your knitting. If you, like me, would like to see the steps of making an afterthought pocket on an actual knitted project (as opposed to a swatch or something like that), here you are:
1) Figure out where you (or whoever you are making the sweater for) want the pockets to be situated. The sweater wearer will undoubtedly have strong feeling about the pocket placement.
2) Mark the center of the top of where your pocket(s) should be.
Cut Snip (sounds cheerier) the marked top center pocket stitch.
4) Unravel an equal number of stitches to the left and right of the marked stitch, I ended up unraveling a total of 13 stitches (I took these pictures when I was being stupid, so there are only 10 in the photos (pretend like you see 13, please)--so not enough. Firstly, not evenly unraveled. Secondly, a gauge swatch could have been useful here, I guess). Again, my pockets were to accomodate a toddler's sweater knit in bulkier yarn. If you knit a gauge swatch, it could actually come in handy at this point for guestimation of how much you need to unravel. You know, if you are into that whole knitting a gauge swatch thing. As an aside, leave the "live ends" from your unraveling intact, they will come in handy at the end to tighten things up.
5) Put the live stitches that are exposed from your unraveling in needles. You will have a top live stitch row and a bottom one.
6) With another needle, bind off the stitches on the bottom needle in applied i-cord. I used the directions on applied i-cord bind-off on knitty.com (scroll down). Do whatever works for you. You just want a good tough "border" on that pocket that won't stretch out with use.
7) Now we are going to knit some stockinette. With another needle, you are going to take the live stitches on the top (now only) needle and knit a "patch." This is your pocket you are knitting now, actually. You should increase evenly to give yourself a pocket with a width that accomodates hands, candy, coins, trains, or whatever you and yours decide to house in your pockets. When it's a suitable lenth, bound off. The stockinette side is going to be the inside of the pocket, so yay, stockinette smoothness. Knit the edge stitches in garter stitch to prevent rolling (or not, if you just want a special sort of challenge).
8) Almost there, let's attach the pocket. Get a needle, it's time to sew. Sew around the edges by picking up ridges from the sweater and your new pocket patch. In some corners of the globe, they call this seaming. I just call it attaching the pocket.
9) Weave in your ends and admire your handiwork. It's a thing of beauty, indeed.
10) If you are opting for a pair (or more, I don't know, go crazy) of pockets, repeat steps 3-9.
11) Pop something in your pocket and pat yourself on the back. You snipped your knitting and produced a place to keep hands warm and collect the detritus of everyday life. Go, you knitting rock star.
This is my first tutorial. I have no idea if it will be beneficial to anyone, but there it is. I am not one to presume to tell anyone how to knit, but I like to see things spelled out sometimes; and, I figure there has to be at least one other person like me who wants to see this process written out and photographed. I am not saying what I did is perfect or the "correct way" to produce an afterthought pocket. It is simply what I did to slap some pockets on my kid's sweater. If you have questions, e-mail me, I feel pretty good about the cutting your knitting for pockets thing now.