A pencil line drawn corner to corner on the wrong side of a square is one of the most familiar marks in patchwork, and one of the few that carries two opposite instructions depending on where it sits. In the Arrowhead Variation block, both appear within the same set of units. Confusing them is not the sort of error that reveals itself at the machine. It reveals itself once the rotary cutter has already been through the fabric.
In the first case, the marked square is laid onto the corner of a rectangle, right sides together and raw edges aligned. The stitching runs along the drawn line itself. The cut is then made beside that line, out towards the outer corner, and what comes away is discarded or set aside. One unit results. The line is the seam.
In the second case, two squares are paired face to face with the line drawn on the upper one. The stitching runs down both sides of the line, never on it, and the cut is made along the line afterwards. Two units result, opened out into their finished shape. Here the line is not the seam at all. It is the cutting guide sitting between two seams.
The block asks for both within the same afternoon, which is exactly what makes it a good place to fix the distinction properly. Once the pencil has done its work, the block relies on nothing more than accurate marking and the willingness to check which of the two jobs the line has been given before the needle starts moving.
Points worth holding on to:
- The line is the seam, or it is the cut, never both. Sewn on, it becomes the seam and the waste falls beside it. Sewn beside, it becomes the cut and both halves are kept.
- Count the units before you stitch. One unit means you are sewing on the line. Two units mean you are sewing either side of it. The expected count is the quickest way to check yourself.
- Mark on the wrong side, every time. Both methods depend on the line being invisible from the front and accurate from the back.
- Sew first, cut second. In both cases the stitching is already holding the layers when the blade goes through, which is the reverse of the order most patchwork follows.
- Set the seam before pressing to the corner. A moment spent setting the stitches keeps the finished unit flat and the point sharp.
Accurate marking rests entirely on a straight edge that does not shift under the pencil. Our quilting rulers are available here and hold their position on the fabric while the line is drawn.
Happy quilting.
