Quarter Square Triangle Units

The Quarter Square Triangle Unit (a.k.a. “The Hourglass Unit” and a.k.a. “Yankee Puzzle”) is basically a 4-patch, except it’s grid is on the diagonal.  Again there are several methods that make quick work out of these units. Two popular methods are the “Quick Hourglass Method” which makes 2 Hourglass units at a time and the QST Ruler method. Traditionally, the unit is made with two light pieces and two dark pieces, but interesting effects can be achieved by playing with the color value when several of these units are put together.

Some examples of blocks that use this unit in their design are:

The Big Dipper

Ohio Star

Practical Orchard

Quarter Square Triangles (Exploded)

Block Examples with QSTs

Here are few examples of blocks that use Quarter Square Triangle Units:

How to Make Quick Hourglass (QST) Units

Making Quick Hourglass (QST) Units is similar to the Quick HST technique, except you start off with larger squares and you basically do the Quick HST technique TWICE.

1. The first time around you make two HST’s from your two fabrics.
2. The second time, you will draw a diagonal line on the wrong side of one of the triangle square units you just made, going from the light corner to the dark corner.
3. Next, align the two triangle squares with right sides and opposite fabrics facing. Sew 1/4″ along each side of the marked line. 
4. Cut between your rows of stiches and press seam allowance to one side.  This will result in 2 Hourglass (QST) Units. 

Cutting Chart for Quick HST Units

Make QSTs Using a Quarter Square Triangle Ruler

To use this method, you will need a QST (Hourglass) ruler, such as the one made by Creative Grids or Fons & Porter. The advantage of this method, is the quick precise cutting method, and how easily these units can be chain pieced, allowing you to cut and sew the units rather quickly.

1. Determine the finished size you need your unit to be.
2. Cut strips from two contrasting fabrics the width indicated by your ruler for your desired finished size.
3. Place two contrasting strips right sides together (RST), making sure the raw edges along the long sides of the strips are perfectly aligned. It is helpful to place a pin in one end of the set to minimize shifting.
4. Align your ruler so that the bottom of the strip set lines up with the marked line for the width of your strip. Cut along both diagonal sides of the ruler.  Place a pin in the pair of triangles you just cut.
5. Turn the ruler 180 degrees and this time align the TOP of the strip with the measuring line  and align the diagonal edge of the cut fabric with the diagonal edge of the ruler.  Cut along the other diagonal. Pin the cut pieces
6. Continue along the strip until you have cut as many triangular sets as possible.
7. Without separating the cut pairs of triangles, take them to your machine and sew along one of the SHORT diagonal sides using a 1/4″ seam. Take care that your layers of fabric are in the same order and that you stitch on the same side of the triangle each time you sew a pair. (This is important, else your units will resemble half square triangles instead of hourglass units!)
8. Open each pair of triangles and gently press to the dark side.
9. To complete the unit, combine two of these sewn units, right sides together with a 1/4″ seam, taking care to “nest” the seams. Press seam to one side. 

NOTE: Since this is basically a 4-Patch, you can “twirl” the center seam open in the back so that the unit will lay flatter.