Curved Piecing Bias Evaluation

I was cutting fabric to prepare to test out the Meringue quilt pattern, and I noticed that I could get a little bit creative and save some fabric if I cut drunkard’s path concave templates differently than I normally recommend in a pattern. Well, one thing lead to another and I decided it was worth a side trip of effort to evaluate where the bias edges fall when piecing curves and the pros and cons of altering from standard practice. Let’s take a look!

Curved Piecing Bias Evaluation – Standard Concave versus Space Saving Concave Cutting Orientation

A standard pattern will be written such that concave templates get cut so that the outside, long straight edges of the template align with the straight grain of the fabric. When cutting concave templates this way, the center of the curve will be a bias edge. And the templates can be rotated along a width of fabric to make the most economical cutting.

I did not have a large enough piece of fabric remaining from my desired fabric to cut my templates in this standard way, but I noticed that I could rotate the template 45-degrees so that the outside, long straight edges of the template are bias cuts. When cutting concave templates this way, the center of the curve will be more aligned with the straight grain of the fabric.

So, I did what any sane quilter would do: I cut what I needed, placed an order for more fabric, and then dug in my fabric bins and decided to test out what it is like to sew quarter circle curves with the concave pieces cut differently. (That is what a sane quilter would do, right? Maybe don’t answer that question, haha!)

Curved Piecing Bias Evaluation – Pieces Cut

To evaluate the difference, I wanted to make sure I was working with the same kind of fabric, so I found scraps of Kona Cotton in Mustard (the lightest fabric / convex shapes), Spice (the concave shape with the edges aligned with the fabric straight grain as typically recommended), and Ochre (the concave shape with the edges aligned with the bias). Note that I am testing this out using 6″ finished templates.

Curved Piecing Bias Evaluation – Pieces Pinned

When sewing curves, I like to pin my pieces together (pinning tip). When pinning, I mark the center and quarter points along both curves. I start by pinning the center marks together, then the two ends, and finally the two quarter points. The reason I pin this way is that with a typically cut concave piece, the short legs of the concave piece are aligned closely with the straight grain and I find it much easier to get the beginning and end pinned before pinning the quarter points because as the curve starts to transition to the bias, it’s easer to flex the concave shape to match the registration marks.

When I was pinning these two different concave shapes, I didn’t notice a huge difference in the way pinning the curves went together. I was trying to keep in mind that the straight edges of the Ochre concave piece were cut on the bias, but in general I didn’t feel like pinning the curve was manipulating those edges in a way that would stretch and distort the fabric.

Curved Piecing Bias Evaluation – Sewn Seam

I did, however, notice a big difference in how the fabric behaves as I was sewing the curve seam. I started with the Spice concave piece which is cut as I am used to. For whatever reason, I tend to struggle to align the raw edges of the seam at the very end of the curve. I think transitioning from straight into bias at the beginning of the seam works well, but transitioning from the bias back to straight grain just tends to take a bit more patience for me.

As I was sewing the Ochre concave piece, the experience was much different. I noticed as I was sewing toward the center registration point that the raw edges of the fabrics were a bit more difficult to keep aligned smoothly. Again, this is absolutely related to the fact that I was sewing at the straight grain area of the concave curve. Transitioning away from the center down to the end of the curve was very smooth and easy as compared to my normal experience, though.

Curved Piecing Bias Evaluation – Pressed Blocks

I like to press my curve seams toward the concave piece, and I generally take my time and try not to distort the block when I’m pressing the seam. Other than keeping in mind that the Ochre edges of the concave shape were bias edges, I did not notice a big difference as I pressed. However, when I photographed the blocks, the edges of the Ochre block do not look like they lay as flat; because of the bias, they are a bit more wavy.

Curved Piecing Bias Evaluation – Trimmed Blocks

Both blocks squared up nicely.

At this point, I am comfortable moving ahead using the fabric saving concave pieces that I cut from fabric, but I will definitely be handling those pieces carefully until they are sewn into the pattern. What that means is that when possible, I will not let the bias edges be on the presser foot side of the seam and I will reduce my presser foot pressure when sewing the block seams so that I do not distort those edges as I sew.

For beginner sewers and sewers new to sewing curves, I would not recommend cutting concave shapes to have bias edges on the long, straight sides. But if you are in a pinch, rotating your template to make good use of fabric (or to get a cute fussy cut print to show), I think you can still obtain a wonderful result with just a bit more care as you handle those bias edges.

Prefer to have your tutorials in video format? Not a problem, I created a YouTube video of this which also includes a demonstration of how the curves came together while I was sewing them at my sewing machine.