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How to Sew Partial Seams with Gigi Levsen

how to sew partial seams
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The world is full of helpful sewing tips and tricks, but there’s one you definitely need to know if you want to create complex patterns: how to sew partial seams. This technique is incredibly helpful when working with curves and fun shapes — it allows for greater flexibility and lots of movements. If you’re new to partial seam sewing or looking to refine your skills, you’re in luck! In this article, we’ll be exploring how to sew partial seams with the expert guidance of Gigi Levsen as she tackles Scott Flanagan’s Starry Sampler featured in McCall’s Quilting.


In the second installment of Starry Sampler, published in McCall’s Quilting July/August 2023, we’re going to make a block using a partial seam. Partial seam blocks are nice because they inherently have a lot of movement, often twisting outward from a center square, and this particular block is no exception. We’ve made a video tutorial for the technique and I’ll explain it here too.

Scott’s original block is made with happy citrus yellow with a lively blue against a creamy white background. As I like to do, I changed up the colors a lot for my version of this quilt! I chose a deep, dark navy tonal for the background. I used a light print in the center and made the surrounding units with a fun blue and purple print.

Scott’s original block
I changed the color palette to give my quilt a different look

Stitch-and-Flip Bonus Units

A quick note about the stitch-and-flip units I’m joining to the center square in this block—the patches in this block are relatively substantial, and you won’t want to waste those stitch-and-flip corners! When I made those rectangular stitch-and-flip units, I sewed another line ½” away from the center diagonal line.

One quick extra step during stitch-and-flip makes a whole other unit!
Cut between the seams for the original unit plus an extra Triangle Square.

When I cut between the stitched lines, I get the original unit for the block AS WELL AS another triangle square unit; if you do the same for each stitch-and-flip corner in one single block, you’ll make an extra 8 triangle squares. I can use these extra triangle square units for some of the other blocks in this quilt (or for anything, really!).

Be sure to lay out all parts of the block before starting to sew.

Step-by-Step Instructions

1

Lay Out Units Before Sewing: For partial seam blocks, it’s really helpful to lay out all the units and patches before you start to sew them together. Arrange the center square and the 4 rectangular units rotating around it as shown in the photo.

Align corners of the first unit and center square.

2

First Seam is the Partial Seam—Sew Halfway Down: Choose a unit to start with and align one edge and corner of the unit with the center square’s edge and corner—the end of the rectangular unit will extend beyond the other edge of the square. In this example, I’ve started with the unit to the left of the center square, but you can choose whichever works best for you. With right sides together, stitch a ¼” seam from the aligned raw edges, sewing anywhere from 1” to halfway along the square’s edge. Stop sewing partway through and remove the partially joined pieces from the machine. Backstitching is not necessary.

I’m pointing to the place the partial seam should stop, about halfway down the center square.
Use your fingertip and nail to press the edge of the partial seam.

3

Finger Press Top of the Seam: Finger press the seam just at the joined end to accommodate the next unit you’ll be sewing. In this case, that will be the unit on top.

4

Ready for the Next Full Seam: You’ll be able to sew the next unit to the long edge you’ve just sewn—press the whole seam this time.

Press the entire second seam with an iron before joining the next unit.
We’re halfway there! Two more units to join to complete the block.

5

Keep Going!: You’ll do the same thing twice more; sew the unit on the right to the center, then the one on the bottom, until all the units have been joined to the center square. Press all the complete seams but not the partial seam yet.

Almost done! You can see the partial seam on the left of the center square.

6

Complete That First Partial Seam: Once all the units have been joined to the center you’ve just got your original, partial seam that can now be completed.

Finish that partial seam, press, and you’re done.

7

Done!: Align the remaining raw edges and finish the partial seam and press to complete the block. Sew easy and sew fun!


Starry Sampler is a bright, bold, dynamic quilt with a lot of different star blocks in different sizes. Most of the quilt is constructed using easy, basic patchwork techniques you’ve probably done hundreds of times, but there are a couple of techniques that some might not be as familiar with — like how to sew partial seams. Be sure to get the July/August ’23 issue of McCall’s Quilting so you can join us on this celestial journey!

 how to sew partial seams
Starry Sampler by Scott Flanagan

Now Start Stitching!

We hope you’ll enjoy experimenting with the technique and join me in sewing a version of Starry Sampler! Be sure to share your quilty creations with us on Facebook and Instagram.

Gigi Levsen
Editor, McCall’s Quilting

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