A smooth grafted seam with chunky wool.

Instead of casting off the stitches in steps as you shape the shoulders, leave them on the needle unknitted. Then, instead of knitting the next stitch in each step, just slip it onto the right hand needle. This makes the shoulder slope smoother. (I always do this with shoulder seams anyway to get a smoother slope.) Leave the unfinished stitches on holders while you shape the second shoulder.

Now take a third needle of the same size and with right sides together, and the needles parallel as shown in the photo, knit one stitch from the front needle and one from the back together to leave just one stitch on the right hand needle. Now knit the next two stitches on the two left needles together in the same way, then cast off the first stitch on the right hand needle over the second as in the normal cast off method.

Continue knitting one from the front and one from the back and casting off as you go, to the end. Finish off the last stitch as normal.

The wrong side looks like this!

And the right side like this.

You could do this cast off the other way round so that the cast off edge is on the outside if you want to make a different look.

The guernseys made here on the island are finished like this with the shoulder seam on the outside and with a knitted row at first as the stitches are grafted together. Then the cast off is done on the next row. There is a picture of this in an earlier blog.

I hope my instructions are clear. It's quite hard, turning knitting into words!