Quarter-Square Triangle (QST) Tutorial

While waiting for enough dark clothes to prewash the additional brown fabric (at $1.50/load, one doesn’t do partial loads), I thought I’d write a tutorial. I’ve seen quite a few tutorials for Half-Square Triangles (HSTs), but I’ve not seen any for QSTs as I learned to make them. So I took photos.

Caution: Before you use this method, analyze your pattern to see if it will work for you because each pair of squares makes two opposite QST parts. It works fine for Hour glass type patterns, as below.

It does not work for star type which requires four QSTs going the same direction, with one exception–shown below.

The exception is to make half of the stars going each way when a plan allows for it. (BTW, I’d not use these colors for a star,but they are what I had prepared for London Roads, and they make the point.)  Note, you have to turn the large triangle as well as the smaller ones. Otherwise you get this hodge podge (or hotch potch, if you are from another part of the country) shown below.

The benefit of this method?  One of the two diagonal seams gets sewn before it is cut, lessening the potential for bias distortion.

OK, you have decided you can use this method.

Those of you familiar with making two HSTs from two squares will note similarities; however, there are three significant differences: the measurement, the first cut, and the trimming.

First difference, the measurement. Start out cutting the squares 1 3/8 inches larger than the desired FINISHED measurement. That allows an extra 1/8 wiggle room for squaring up later–cut 1 1/4 only if your quarter inch seams are perfect. (I’ve known some who scorned the wiggle room, but I felt better about my need to trim when Sally Collins–of Mastering Precision Piecing–also recommended the extra 1/8 inch.) My goal is 5-inch (finished) squares so I cut 6 3/8 inch squares.

Mark one diagonal line. A see through ruler helps to keep the line at the corners.

Stitch 1/4 inch on each side of the line.

(As aside here. I’ve seen this tool, Clearly Perfect Angles by NewLeaf, for stitching without marking; it would be quite a time saver. Has anyone tried it? What do you think?)

Second difference, the first cut.

Here you can see the drawn line and two seams. (My apologies for the reflection of my ceiling light–I’ll replace the photo when I get one without the circle!) Your first cut is perpendicular to the seam, as shown above .

The second cut is on the pencil line, shown below.

If you are feeling very brave, you can line up two at once or even stack two. I do mine individually. (BTW, the tape over the “Creative Grid” label is where I write my initials when I am sewing in a group and we might get rulers mixed up. I figure I already can’t see at that spot, so it is a good place for tape. I’m not hiding the label. I like the rulers.)

Next  press the seams. I press to the darker fabric so that I can nest the seam allowances and match the center seam when sewing the next seam. No harm in pressing open and securing the match whatever way is comfortable for you.

As I said at the beginning, half have the dark to the right and half to the left.

To make the hour glass square, take two that go the same direction and place them opposite each other. As below.

Seam and press. Now the square is ready to trim, the third difference from HST construction.

Note the diagonal marked on the square ruler.

There are varieties of square ruler, and many have this line. You need it for this trim (as you do for HST trim).

Below is the positioning.

Whereas for the HST you need only have the diagonal on the seam and to be sure your piece extends beyond your desired measurement, for the QST you need to center the point where all four meet AND be sure the piece extends.

My goal for a finished square is 5 inches, so I will trim to 5 1/2 to allow for seams. Place the ruler so that the diagonal follows one seam line and the four corners show the 5 1/2 mark on the seam line (as above). The center falls at 2 3/4. You could just go by the math (half of the 5 1/2 you are cutting), but I like to check the corners too for an extra check.

Trim two sides. Turn, place the ruler on the other diagonal and trim the last two sides.

The QSTs are ready to assemble into whatever block/pattern you desire–mine will end up in the London Roads quilt, probably next week.

I’ll be linking with tips and tutorials on Tuesday. Button in sidebar.

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