Wednesday, March 28, 2012

Half Square Triangle Tutorial - Bias Strip Method

Hello Friends!

When I was getting ready for the sew day, I wanted to start a new project that needed 400 half square triangle units.  Often when making multiple units like this, I use Triangles-On-A-Roll.  When checking, I had none that finished to a 2" square.  I had a lot for finishing to 1-1/2" which is what I normally use.  This time, though I needed 2" finished.

My second favorite way to make multiples of half square triangle units is the bias strip method.  Since this was to be a scrap quilt, that meant a lot of fabrics. This was a piece of cake to do using this method.  The quilt I showed you here was made using this method on fat quarters for the half square triangle units.

With this method you simply need to cut bias strips the width of the unfinished square that will be produced when sewn and cut into the units.  In this case that was 2-1/2".  I tried a 9" square of a light and dark fabric, but that left waste fabric and only produced 14 half square triangle units, so I decided to go with 10" squares.  It would have made it a bit easier if I'd used 10-1/4" squares as the two corner units were really close!

Here is how to make h/s triangle units using bias strips.

You will need, fabric, rotary mat, rotary cutter, rotary rulers - both long and square with a diagonal such as That Patchwork Place Bias Square Ruler, your iron and starch* (optional) and, of course your sewing machine.   *Starched fabric is easier to work with in this method -- I starch it fairly stiff.

 Layer two squares (one light, one dark) right sides up.  Fat eighths or fat quarters can be used or any size square depending on how many you want/need.  Squares are just easier to determine the 45 degree angle cut.

I usually put the light fabric on top as the markings on the ruler seem to show up better.

Determining the 45 degree angle for a square is a simple matter of laying the ruler from corner to corner.  If you use a rectangle, you will need to use the 45 degree angle on the ruler to make the first cut.  Do this from one of the corners just as you see here on the square.

Make the first cut diagonally from corner to corner or from the corner at a 45 degree angle on a rectangle.

Measure the desired amount.  This would be the size of the finished half square triangle you desire plus 1/2" for seam allowances (1/4" all around).  In my case I needed a 2" finished half square triangle unit so my cuts were 2-1/2".

Continue to cut strips measuring from the cut edge.

The first half is cut.  If you are using a rotary mat that can be turned, turn to cut the second half or move to the other side of the table, or simply rotate your full sized mat, if possible.  If you cannot rotate the mat, turn the uncut portion so that it will be easier for you to cut with your dominant hand.

Continue to cut strips in the desire size until all fabric is cut.

At this point, the strips need to be arranged for sewing.  It is easier to do this on a flannel covered board.  This one is simply foam core from the craft store with flannel fabric stretched across and taped to the back side of the foam core..  Alternate the strips as shown.  (Two sets fit on my board.)

The lower left strips have been partially sewn in this photo.

When sewing the strips, those left of the center cut will be offset with the bottom corner offset.

On the right of center, the top corner will be offset.  It will ALWAYS be the pointy corner that is offset.

The center strips will be even as both are pointy.

Hint:  I sew pairs of strips together and then sew those into quads, etc. moving across the fabric strips from left to right.

Continue to sew strips together until your "squares" have two even sides and two irregular sides as shown below before they are pressed.

You can press either to the dark or open.  Always press open for smaller half square units.  I do this for most sizes, though traditionally we are taught to press to the dark.  It's your choice. Once pressed, they look like this.

Hang in there, the magic begins now.  This seems like a lot of work, but it is so worth it when you see the perfect pieces you will make using this method.

Starting with the straight corner, place a square ruler that has a diagonal line on the seam with the measurement of the unfinished square size you need.  You can see here that the edge of the ruler is at 2-1/2".  This is the bias square ruler made by that Patchwork Place.  There are other square rulers that will work as well, this is just my favorite as the markings are easy to see.

Cut the first two sides of the half square triangle unit using your rotary cutter.

Rotate the cut piece so that you can cut the other two sides to complete a perfect half square triangle unit.  These cuts take care of the dog ears you would have to cut off any way.

There is very little waste on the first cut.  Other cuts will sometimes have more waste.

You will now have two points.

Repeat the placement of the ruler on both of these points, rotating the squares to finish cutting all sides as you did for the first point.

Now you will see three points.  Keep repeating the cuts revealing the next points to be cut until all fabric has been cut into half square triangle units.

You will quickly have a stack of these units ready to use.

This is an easy way to make half square triangle units for a scrappy quilt.

Here is my tray full of half square triangle units, squares and some of the halves of 4-patches needed for the quilt I'm working on right now.

I hope you have found this tutorial helpful.  If you have any questions, please feel free to either make a comment below or e-mail me with your questions.

May your quilts be wonderful and your preparations quick and easy!  Enjoy.



JoQuilter said...

Lois, that's just a lot of work to make some simple half-squares. Isn't it funny how people many different ways there are to make a simple half-square block. But my real question is, what is the finished size of that little square? Please let me know. Thanks, Jo

Lois Arnold said...

Jo, I would agree if it were ohly a few but when 400 are needed, it really is faster. I did all of these in really very little time. In my example, the half-square triangles finish to 2" because I used 2-1/2" bias strips. If I had used 1-1/2" strips, they would have finished to 1". I know you like to work bigger than that and your quilts are awesome. Do what works for you!

Joyce said...

Love the technique. Have never tried it before. I can see that it would be very easy to get a really scrappy look if you used strips from several different fabrics. Thanks for taking the time to show us!!

Lorinda said...

Would it work to cut strips or do you lose accurqacy? I find it hard to cut corners using rotary cutter without cutting into surrounding fabric.

Deb said...

Good point, Lorinda. I was wondering the same thing.

Lois Arnold said...

I think I tried it that way once, but it didn't seem as accurate. There is really very little waste using this method and though you overcut a hair or so on the corner, it all works out because the next cuts are on the next set of points sticking down. By all means try it and you might like doing it that way. This is just one of the 5 methods I use for h/s triangles depending on how many I need and how much variety I want. There is no one right way to do anything in quilting!


Why can't you just cross cut strips the desired width of your hst and then cut the strips down further to the size of the block you are trying to achieve?

Lois Arnold said...

Sylvia, You could try that, but it really is easy to do it this way, especially if you are going to have to cut down to size anyway. I think it would just be more time consuming. This method is aactually quite fast to do and the hst are perfect every time.

tink's mom said...

This is a very interesting concept. I need to give it a try on my next quilt. Thanks for sharing it with us.