Wednesday, December 19, 2012

Let Me Count the Ways ... to make Triangle Squares

The last few times I've put together directions for making a quilt block that has half-square triangles (HST), aka Triangle Squares, as one of it's components, I've left the specifics of how you cut and sew those units up to the quilter.

Today, it occurred to me that it could seem a little bit like a cop out, a bit like quilt as desired.

So  while I was making some new blocks that had triangle squares as a component, I tried making them  a few different ways and thought about the list of ways to make them.  

I can't share the blocks I made for another week or so, but here's my list of ways to make triangle squares. Did I include your go-to method?

One Triangle at a Time

Cut individual triangles by:
  • Cutting a square 7/8-inch larger than finished size and cutting it in half diagonally, or
  • Using a specialty ruler or
  • Using a die-cutting machine. 
Pair triangles together and sew together to form a triangle square.

USE this method when you want unique, scrappy combinations and are comfortable working with bias edges.

One Triangle Square (HST unit) at a Time

  • Cut two squares that are the SAME size as your desired UNIT size

  • Stack the two fabric squares with right sides together

  • Draw a line diagonally from corner to corner on the top square
Sew ON the drawn line

  • Trim ¼ inch from the seam (on the side you don’t want to keep

  • Sew the small triangles together for a smaller bonus square.

USE this method if you only need one HST unit or if you want to control the direction of stripes and other one-way fabric designs

Two (HST units) at a Time

  • Cut two squares that are 7/8-inch larger than your desired FINISHED size
  • Stack the two fabric squares with right sides together
  • Draw a line diagonally from corner to corner on the top square
  • Sew on each side of the drawn line, ¼-inch away from the line
  • Cut on the line to create two HST units. 

USE this method if you want to avoid techniques that require cutting/sewing bias edges.


Instead of drawing the line first, cut the stacked fabrics diagonally from corner to corner and sew the triangle pairs together.

USE this method if you like to use a ¼-inch foot with an edge guide and are comfortable sewing bias edges

Four Triangle Squares (HST units) from Two Large Squares

  • Calculate the size of large squares by dividing your desired UNIT size by .64 and round up to something measurable.  For example, if you want a 2” finished size triangle square, take 2.5 (the unit size) and divide by .64 for 3.9 inches, which I rounded up to cut two 4-inch squares. 
  • Stack the two fabric squares with right sides together
  • Sew around the outside edges of the square
  • Cut diagonally  from corner to corner in both directions to create 4 units
  • Press and square up to the correct size.
WARNING: This method results in HST units with bias on all sides.  USE this method ONLY if you are VERY comfortable working with bias edges.

Using Printed Foundations to Make Triangle Squares

Printed Foundations for making HST units are available commercially as strips  or sheets from several sources and are also available as free downloads.  This example, for 2-inch (finished size) units, came from here.
  • Cut the sheet to a size appropriate for the number of triangle squares 
  • Cut two pieces of fabric to the same size as your paper foundation
  • Use a smaller stitch length and stich through the stack of foundation and fabric
  • Cut along all solid lines to create HST units.  
USE this method if you need to make MANY matching HST units  beginning with large pieces of fabric or if you are working  with pre-cut strips.  See the Thangles website to see how this technique works with their strip-based product.

Making Many HST Units from Bias Strips

Create a striped fabric square from bias strips cut as wide as your desired UNIT size, alternating your two fabrics, then starting at one corner, cut  HST unit squares. 

USE this method if you need to make MANY HST units from two fabrics, are comfortable working with bias edges and don’t like removing paper foundations. 

I haven’t yet tried this method, but found a good tutorial on Lois Arnold’s blog, here.

Download a print-friendly copy of this info (with more in-progress photos) here:

Sophie's Tips for Making Half-Square Triangles


Mandy said...

Far out! I never realised it was so technical to cut out a couple of triangles! lol
It is very good to read all the options in one place together. Interesting. It's one of those things that if one tutorial doesn't work in someones mind there is another one that does the same thing that might!
Good job on that post!

SarahZ said...

I love HSTs!!! I've used a few of these techniques, and love learning new ways to make them!

Lynette said...

And have you seen the way to make 8 from two large squares? :) I stumbled onto that one recently, and really love that it's as easy as the 4-in-one but doesn't yield all those bias sides.

sophie said...

Uh oh. I may have to try this one and update my list! Thanks for sharing, Lynn!

lj_cox said...

My go-to method is the add 7/8", draw once, sew twice variant. Though I add 1" and trim, because my triangles are just a scosh wonky as sewn.

I've done the paper foundation version and it yields great triangles but ugh, the paper removal.

sophie said...

I probably should have mentioned rounding 7/8 to 1 and trimming. I thought it might confuse the math and was trying to keep it simple, but I know a LOT of quilters that make HSTs just that way. Maybe when I add the 8-at-once variation, I'll include that note.

Nann said...

Put me in the column for "round up and trim down." But I cut the squares on the diagonal, then sew the seam -- I think it's extra (and unnecessary) work to draw drawing a diagonal line before sewing and cutting.

Anonymous said...

I've done all of those at one time or another. =) To make them perfect, I cut squares that are 1" larger, press one square down the middle, sew on either side of the fold 1/4", press and square up. I like the perfection of the printed papers, but I hate taking off the paper, even with the fold and snap method. I still do that if I need hundreds, though.

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