A Shell Tuck Stitch, also known as Picot Hem Stitch, is a decorative stitch that creates a scalloped edge. It is used to add a trim-like effect to necklines and hems on knit tops or on the bias (stretch) edge of woven fabrics. This tutorial is primarily focused on using the Shell Tuck Stitch on knits, which adds a lovely subtle detail that really elevates the look of a simple basic. We will be applying this technique on our pointelle fabrics, which itself has little openwork details. The shell or scalloped effect of the Shell Tuck Stitch is a perfect complement to the dainty details of our pointelle fabric.
The Shell Tuck Stitch alternates between stitching at its straight stitch line and dropping off the fabric. See above for the stitch symbol and a contrast thread photo of the stitch. The drop off at the edge of the fabric is what creates the “tuck” effect — when it returns to the straight stitch line, the stitch pulls in the edge of the fabric to create the shell. The stitch length is the straight stitch distance between each zig zag, which you can adjust to create small to wide scallops. We will show you how changing various parameters like the stitch length will effect your outcome. But first, we need to prep the machine.
Prep the Machine
1. Set your stitch to the Shell Tuck Stitch.
The Shell Tuck Stitch (photo above) is usually a later stitch on your machine. It is the vertical mirror image of the common Blind Hem Stitch.
2. Adjust the Stitch Width (turn to highest: 5). Width is the distance between where the needle drops off the fabric and where the straight stitch line is.
3. Adjust the Stitching Length (between 2 and 3). This will vary the length of each scallop. The smaller the stitch length, the smaller the scallop. We suggest starting between 2 and 3.
4. Adjust the Tension to the highest setting (VERY IMPORTANT). The tension is what pulls in the thread to create the scallop and also helps prevent your fabric from stretching out during the stitch. If your tension is low, your scallop may also be not very pronounced. How high the tension needs to be may also depend on the thickness of the fabric. For thicker fabric and more layers, you definitely need the highest setting. If you use a thinner fabric or fewer layers, you might find the highest setting is tightening your scallop too much. In that case, you can decrease the tension until it gives you the desired effect. We recommend starting at the highest setting and adjusting depending on your outcome.
Testing the Stitch and Pressing
Practice makes perfect. You probably want your decorative stitch to look as neat as possible, because it’ll be an eye-catching detail. When you first attempt this stitch, you want to practice feeding the fabric in a straight line so that the zig zag drops off the fabric at the same place. This takes some getting use to. I use my hand to guide the fabric on its side.
5. Practice the stitch on a scrap piece of fabric with the same thickness as your intended project. If your neckband of interest is two layers of fabric, then you want to practice on an edge that’s two layers thick. Neckbands and straps can be 2, 3, or 4 layers depending on your technique. Hems are always 2 layers of fabric.
6. Press with an iron after sewing to relax the fabric. After doing the stitch, the scallop might look a little stretched out. Press the scallop with an iron and guide the knit to its original shape. If your tension was set correctly, it will relax after pressing. If your tension was too low, it won’t be able to relax to its original shape. See below image. Regardless, pressing is super important.
7. Repeat step 5-6 with different parameters to see which type of scallop you like. You can vary the drop off position (where the needle zig zags to) and also the stitch length to create different effects. I prefer dropping the zig zag near the edge of the fabric.
8. Apply on your intended neckline or hem! Don’t forget to press. Before attempting on your neckline, put on your shirt to make sure the neckband without the scalloping fits well as is.
Alternatively, you can make your scalloped band first, then attach the band following the instructions of your sewing pattern. There are upsides and downsides to doing it this way. If you make the scalloped band first, you can see that the scalloping was done correctly (band lies straight after pressing in Image 5), and if you mess up, you can cut a new band and try again. The downside is you won’t know if you like the look and fit of the garment until everything’s attached. If you feel confident about attaching bands, have already made the same shirt before, and know that you like the neckline and style, you can do the scalloping on the band before attaching it to the neckline. If it’s your first time making the shirt or your first few times attaching neckbands, we recommend attaching the undecorated neckband first, then decorating it. This doesn’t apply to hems, which you have to hem first before applying the decorative stitch.
I like doing the scalloping on necklines and sleeve hems. For the V neck wrap below, I used a longer stitch length of 3 which in my opinion complements the high angle of the V. For the scoop neck, I used a shorter stitch length of a little over 2 to go with the more rounded curves of the scoop. The V scalloping is done on the neckline band that’s 4 layers of fabric and the scoop neck is done on neckline band that’s 2 layers of fabric.
Scoop neck baby tee
How to salvage your work if you mess up
Applying the decorative stitch can be daunting. What if you mess up? After unpicking the scalloped seams, you might find that the fabric got too stretched out and doesn’t look like the neckband you started with. Your shirt and all your hard work sewing it are not ruined! After removing all the scalloped seams, toss the fabric in the washer and dryer. I’ve found this to be the easiest way to get the band to relax back to its original form. And it does do that.
Let me know if you have any questions! This definitely takes trial and error so save those scraps!