As a quilter, you're constantly told to make sure you sew a 1/4" seam. It's something that's ingrained in every seam you sew and may well be one of the most important things about quilting, depending on the types of quilts you make. Once again, all these triangles I've been sewing recently were an eye-opening experience and good reminder about this 1/4" rule.
I have a 1/4" foot. People use all different methods to get their 1/4". I like my foot. Unfortunately, it isn't always accurate. While sewing the blocks for the [3 x 6] Bee, I noticed that some of my seams were a bit over 1/4". Not by much, but enough so that when all the seams were added together, the entire 12.5" block was off by 1/32" to 1/16". I know that's not much and can be easily stretched or ironed out. But it's still irksome.
I did some sleuthing. It turns out that the guide on my 1/4" foot is somewhat flexible. I need to go look at another 1/4" foot to see if they're all like that or just mine. In the mean time, I did some testing and discovered that I need to move my needle over one step to the right to get a 1/4" seam.
This is is the default stitch width setting at 3.5. As you can see it's a bit larger than 1/4". It's like one thread of fabric larger, but still larger. It adds up over the course of several seams. (I made two seams to further test my hypothesis. The seam on the left is the original and the one on the right is one click to the right.)
The basic quilting stitch on my machine, the one that it defaults to when you turn on the machine, doesn't allow you to adjust the stitch width (darn), so I had to re-program the second quilting stitch on my machine. Luckily, I can save that setting and still use my 1/4" foot. On my next trip to the quilting store, I'll take a look at another 1/4" quilting foot.
Anyone else have this problem? How do you make sure you have a 1/4" seam?
The moral of the story: measure your seams and do a couple test seams to make sure they're really at 1/4". If your seams aren't 1/4", figure out how to move your needle.