I've been trying the shirring technique. My first WHOLE spool of elastic thread (that's 30 yds) went to practicing with absolute failure. Ms. Imagination said that she couldn't get the gathers to happen, and that's exactly what I was coming up with. Nary a gather to be found even after I steamed and steamed! Frustration!
I was also having tension problems with the bobbin which is where the elastic thread goes. The back is supposed to look nice and neat (see step 2), but instead mine looked snarly. I tried every stitch length and tension possible, but could not get any consistency.
I went to several other shirring tutorials for help: House on Hill Road has a very detailed tutorial - more so than the Heather Ross segment, because you can see what she's doing close up. But Pretty Ditty is where my problem was discovered. I didn't even find it in the instructions, but in the pictures. She has a drop in bobbin, as do I. After she had pulled up the bobbin thread, the thread came across like it does with regular thread. Mine was not set right. It was coming straight off the bobbin directly through the opening by the needle.
No wonder my tension was screwy! That's like having no tension at all! Threading a bobbin of elastic thread through my machine took a little effort, but after I got my bobbin set and threaded correctly, the first practice row gathered up perfectly.
The tension was perfect as well. I used a stitch length of 4.0 and my tension was set for about 5 1/2.
***At the time of this post I didn't really know how to explain what was happening and how I fixed it. I have explained it better in this post!