Sewing Half Square Triangles With A Grid

Yesterday we started on this holiday table runner by picking some fabrics, cutting the pieces and marking out the grid for the half-square triangles (HSTs). Today we’re going to be sewing the half square triangles with a grid method that makes for fast and easy work of creating multiple HSTs.

Sewing the Grid

Place fabric piece D which has the grid marked on the wrong side on top of fabric piece A with right sides together. You can see the colored fabric behind the white in the photo below. The grid lines should be facing up.

You may wish to pin the pieces but with it only being an 8 inch square there should be little movement or shifting of the pieces. If the pieces were 4 x 20 inches then pinning is definitely a good idea.

Begin at one corner and sew a ¼″ seam along one side of the diagonal pencil line. Last month when I was making the mug rug I used the perfect quarter inch foot which has a guide to run along the edge of the fabric. This foot is not the ideal foot to use when sewing down the centre of a piece of fabric so I switched to the regular quarter inch foot that doesn’t have a guide.

With this quarter inch foot I lined up the pencil line so the line ran down the middle of the wider toe of the foot to create a quarter inch seam.

Repeat for the other side of the diagonal line.

Cut apart along the pencil lines to create 8 triangles.

Press the HST open with the seam going towards the darker fabric. I unfortunately do not have a photo to show you of the HSTs pressed open but one side is white and the other side the red circle print.

Repeat the grid method with the other two 8 inch squares.

I just love sewing half square triangles with a grid and now it’s time to turn these half square triangles into quarter square triangles.

Making Quarter Square Triangles

A quarter square triangle (QST) is technically made up of 2 half square triangles with 4 equally sized triangles within the square are made up of 4 different fabrics but sometimes the same 2 fabrics or maybe only 3. The block that we’re making today is made the same as a QST but has two small triangles and one large – maybe it should be called triple square triangle instead.

Begin by drawing a line on the wrong side of piece C from one corner to the opposite. One again I used a regular pencil as the line will never be seen.

Place piece C on top of the HST made yesterday with right sides together with the pencil line on top.

Note in the photo above that my green square is slightly smaller than the HST. This is because I cut it at 3 ½″ rather than 3 ¾″ which is what is in the directions. Because I gave lots of extra fabric this will not be a problem and I made sure the diagonal line was lined up corner to corner with the HST underneath.

Sew a ¼″ seam down one side of the line lining up the foot the same as when sewing the HSTs with the grid method. To speed up the sewing use the chain sewing method. This is done by lifting the foot slightly when you come to the end of the square and slipping the next square under the foot ready to sew. Not only does it save time but it also saves thread as you are not constantly starting and stopping and having a long tail of thread with each piece.

Chains can be as long as 2 pieces to 200 or more pieces. Did you notice that I have an extension table for the Pfaff Ambition 1.0 this time around? It sure is nice and I love how the feet are built right in and their height is adjustable. Having the extension table sure makes it much easier for sewing.

Sew a ¼″ seam down one side of the line lining up the foot the same as when sewing the HSTs with the grid method. To speed up the sewing use the chain sewing method. This is done by lifting the foot slightly when you come to the end of the square and slipping the next square under the foot ready to sew. Not only does it save time but it also saves thread as you are not constantly starting and stopping and having a long tail of thread with each piece.

Chains can be as long as 2 pieces to 200 or more pieces. Did you notice that I have an extension table for the Pfaff Ambition 1.0 this time around. It sure is nice and I love how the feet are built right into and their height is adjustable. Having the extension table sure makes it much easier for sewing.

Last month I made my own extension table using thread containers.

When finished leave the chain intact and start sewing a ¼″ seam along the other side of the pencil line. Having the IDT system engaged will help to smoothly feed the squares under the foot and over the feed dogs.

Clip the chain apart when finished and cut along the pencil line to create two triangles.

Press open towards piece C. Square off the QSTs to 2 ½″ using your favorite method and ruler.

One thing I did find when I was starting to sew with the Ambition 1.0 that if I didn’t have a long tail of thread it very often was pulled back up through the machine and out of the needle. I rectified this by wrapping the thread around my fingers when I was first starting to stitch.

With the QST’s made it’s time to put the block together but that can wait until tomorrow. Isn’t sewing half square triangles with a grid the best thing since sliced bread?

Happy Quilting