Perfect Half Square Triangles Every Time

[Edited January 13, 2020]

There are many ways to make half-square triangles (HST) and I use them all, depending on the project I am working on or, most likely, depending on the size of the HSTs used in the project. Sometimes, the size is so unusual that I need to make them the old fashioned way – stitching two triangles together. Let me show you how to make Perfect Half Square Triangles Every Time.

I have been making a lot of half-square triangles lately as I test patterns I designed. Of all the methods I have tried, I find myself using this one often which I will demonstrate today. It involves using a ruler that I have had for a very long time but never used before (I am the only one who does that, right?). 

The ruler is called Strip Tube Ruler and it is super super easy to use. I could not find any directions with it (I told you, I purchased it eons ago) so I went to their website and printed out the two-page instruction sheet. OMGoodness – I don’t think I will stop making HSTs any time soon.

Here is how you use the ruler:

Stitch the fabric strips together.

With RST, stitch together two strips of fabric on both long sides. The width of the strips will depend on the finished size of your HSTs. I press the strips after stitching to set the stitches.

Position ruler on strip and cut.

If you want, say, 3″ HSTs, place the line on the ruler which corresponds to 3″ on the bottom seam line and cut on both sides using the rotary cutter.

Then, flip the ruler and this time place the 3″ line of the ruler against the top seam of the strip (or tube).

Cut it and flip the ruler again, placing its 3″ line on the bottom seam of the strip set. Repeat these steps until you have cut all the HSTs you need. 

Press open.

Then, press them open and trim the ears. There is hardly any waste of fabric and stitching two long strips of fabric together beats the traditional method of drawing a diagonal line on the back of one of the fabric squares and stitching 1/4″ away on both sides of the line. As I said, you can make perfect half-square triangles every time with this ruler!

This ruler has been placed on the very front of my ruler rack now. The best part of it is that you can make HSTs from 1-1/2″ all the way up to 9″ with no fabric waste. However, you can actually make them smaller by making the 1-1/2″ size and then trimming it down to your desired [mini] size.

Which method do you prefer for making HSTs? Have you seen this other method I use? Have you tried this one using a strip set (or tube)? This is such a breeze now… No more cutting patches with weird measurements. It works for me!

Have fun today,