wading heron is the quilt pattern used in this image

What's tunneling and How to Overcome It

Tags: applique stitching, sewing, tunneling, zigzag

A couple of weeks ago I wrote a blog post about free motion zigzag. I had a question about the fabric bunching up under the stitches so thought this was a good opportunity to show you how to avoid that.

Zigzag capabilities are available on even the most basic machines and though it is a simple stitch it can be used in many different ways. An open zigzag can be used as a seam finish, to secure the edge of an applique, or for couching ribbons and yarns.

I've made a sample showing the different effects that can be achieved simply by adjusting the width and length of the stitch.

  • You will notice that the longer the stitch length gets, the farther apart your zigzags will be and the faster you will move along the fabric. If you use a short stitch length like .5 mm or less, you will get a satin stitch.
  • If you move the stitch width, your stitch will get fatter or skinnier. 

zigzag sample: shortening and lengthening the stitch (top) narrow to wider (bottom)

Take some time to play with your zigzag stitching. Your stitch should look the same from both sides however I tend to have the bobbin tension slightly tighter to unsure it never shows on the top. A little of the top thread showing underneath is okay. To make any adjustments, follow the same rules for adjusting tension for straight stitch. You may need to refer to your manual for this as all machines are different.

When stitching on one layer of fabric you will more than likely notice the fabric will bunch up. This is known as tunneling. Avoid this by using a stabilizer underneath.

sample of tunneling with zigzag stitching
sample of tunneling

If you are neatening a seam edge, it isn't always easy to add a stabilizer so you will want your stitch length to be longer and hold the fabric firmly as you stitch to avoid this. 

For applique, in particular satin stitch, you will need to use a stabilizer so your stitches lay flat against the surface. I usually work on a layer of fabric and batting and find a medium-weight stabilizer works fine however if you work on fabric alone, then a heavier weight stabilizer is needed. This sample is a fabric sandwich with batting and no stabilizer, you can see the tunneling is happening a lot less than the sample above.

Sample has batting and no stabilizer

Depending on the fabrics and layers you are using, if your fabric begins to tunnel, or pull in, then you need additional stabilizer. It also depends on the width of your stitch. Very narrow stitches are less likely to bunch up, whereas wide stitches are more likely to. 

To help keep your satin stitch flat, you may want to switch to your embroidery foot as the bottom of the foot has an will pass smoothly over the dense stitches. I use my open embroidery foot which gives a clear view of the stitching as it is being done.

open toe embroidery foot under side of an embroidery foot for sewing machine
open-toed embroidery foot

Note: the photo of the quilt in the header is called "Wading Heron" by Anita Eaton. It uses satin stitch and the pattern is available here: Wading Heron quilt pattern

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