New Orleans House Project

Thursday, March 17, 2016

Mass Quantities of Half Square Triangles

One of my goals for the first part of 2016 was to finish my Quilt Like An Eagle quilt top.  I was kind of dreading the last step in my design, because it involved making a LOT of half square triangles.  

My plan was to make a dog-tooth style border using HSTs.  After auditioning a couple of different sizes for the HSTs, I settled on 2 1/2" finished blocks.  What the heck - I only needed a little over 100 of them!

Since I usually make HSTs a few at a time using the Easy Angle ruler and scraps, I knew I needed a different technique for this project.

I pulled out one of my handy-dandy quilt reference tools:  All-In-One Quilter's Reference Tool by Harriet Hargrave, Sharyn Craig, Alex Anderson and Liz Aneloski.  The book had a great set of diagrams for making 8 HST units at a time from two fabric squares AND a table listing what size squares to cut based on the finished HST unit needed.  I quickly made a set of HSTs using their instructions and measurements, only to find the blocks were too large and would all need to be trimmed to size.  

So sorry, but I'm from the "measure twice, cut once" school of quilt block piecing.  I really don't like to cut my HSTs over-large and then trim them, especially if I'm making mass quantities of HSTs!

I decided to consult my other favorite reference, Google.  I found Karen Walker's "Magic 8" tutorial for the same HST process, but she included the math for figuring what size squares to cut.  The simple trick is to add 7/8" to your finished HST unit size, then multiply that number by 2.  That calculation will result in HSTs that don't need trimming.  She does note in the tutorial that you can add an extra 1/4" to your cutting measurement if you WANT oversize HSTs.

Once I did the math, I was ready to start making lots of HSTs.  Based on the math calculations, you cut two squares of fabric (in my case, light and dark), and layer them right sides together.  Draw a line from each top corner to each lower corner, forming an X.  Stitch a 1/4" seam on each side of the diagonal lines - there will be a set of parallel seams following the X.  Now cut the block in half from top to bottom.  Without moving anything, cut the block in half again from left to right.   Again, don't move the pieces, but cut along both of the lines forming the X.  You should have 8 triangles showing when you're done cutting. 

Press the triangles open and do a happy dance because you've just made 8 HSTs!  
Do  little more math and figure out how many squares you need to cut to make the remaining 90-something HSTs for the border...
Once the border is finished, I'll post full pictures at Quilt Like An Eagle.


  1. Persevering with finding the right technique has paid off for you! I really don't like trimming either. :Q

  2. Those look great, I would be doing a happy dance too! I don't usually use this method, so it's nice to see the steps, thanks!

  3. Way to "geterdone", it's going to look fabulous!

  4. Hooray for the maths !! Your border is going to be sooo nice !

  5. I like using Triangulations for HST's. Just stitch on the lines, cut, and done.

  6. Yay! I've used a modified version of that trick, and love it. I don't like unnecessary trimming, either. 8)
    Looking forward to seeing those borders done!

  7. Magic 8 is DEFINITELY the way to go when making multiple HSTs!!

  8. Looking good! Hst's are definitely not one of my favorite blocks to be making multiples.:)

  9. A speedy and accurate solution to a tedious step!