It has come to my attention that seaming can be quite a cause for anxiety. Having grown up with vintage patterns (which would lead one to think that knitting in the round had not yet been invented), seaming has become an essential part of my knitting repertoire. I took some pictures today to show how I seam. My basic technique is the mattress stitch. Unfortunately, unlike the diagrams in most mattress stitch tutorials, I typically don’t have a straight, tidy row of edge sts. Not even if I slip an edge stitch for seaming, though that does help somewhat. Nevertheless, sometimes there are circumstances (e.g. lack of forethought) when you don’t have a tidy edge.
I fold it in half and pin it together, as if it were a piece of fabric. I then place the pins a couple of stitches in from the edge, making sure to pin at the top and bottom edges, and at the transitions between stitch patterns that need to align. If the piece has a clear center, I align the centers and pin there. It doesn’t matter that the pin heads are small enough to slip through the knitted fabric. There won’t be much tension applied to them in the process, their main purpose is to keep things from shifiting around.
Note that I am not pulling as tight as I should, in order for the stitches to be clear for photos. Normally you’ll want to pull enough for the sewing yarn to disappear into the fabric.
Now that the very ends of the swatch are secure, I’m a little more careful about stitch placement. I run the sewing yarn perpendicularly across the seam line, and insert my needle one stitch from the edge, along the line that the thread marks:
I could be tidy and undo the seam until the bubble disappears, and then redo it. But I’m too lazy for that. As soon as I notice the bubble, with the yarn opposite to the side that’s bubbling (has excess fabric), I determine the position of the next stitch by pulling the sewing yarn diagonally across the seam line (instead of perpendicularly as above), and insert the needle at that point:
Continue as before all the way up the seam, and you’ll have a perfectly seamed garment!