Why Add 1 inch When Making 1/2 Square Triangles?

Why add 1 inch when making half square triangles


Learn why quilters prefer to add 1 inch rather than 7/8 of an inch when cutting out sets of half square triangles.


Brilliant video.

This will work really well for me as I’m new to all this (so the more fabric there is, the better LOL).

Thanks for sharing. Brilliant video.

Lee X


download transcripts Video Transcript: CUTTING AND SEWING HALF SQUARE TRIANGLES - Why Add 1 Inch When Making ½ Square Triangles? (#5 of 8 videos)

When I make ½ square triangles, I like to cut a square that’s at least an inch bigger than the finished size in order to get my two ½ square triangles. The reasons why I like to do this is:

  1. It’s easier to add 1 inch rather than 7/8”
  2. The extra allows me to be more accurate and clean up any mistakes.

Let me show you what I mean. Here I have a square formed from two ½ square triangles where I followed that 7/8” Rule. And over here I have a square made from two ½ square triangles where I’ve used the 1” Rule. You’ll notice that this set of triangles is just a little bit larger than this set. I have to cut this down into a 2 ½” square which is an extra step but I think it’s worth it.

If I look over here, you’ll notice that I have to cut these little ears off here to get this into a square but I’m going to have some problems here. Let me show you what I mean and to do that I’m going to have to zoom in on this.

I’ve cut the ears or the tips off of this triangle. You’ll notice that the diagonal here in this corner, is off a little probably because the fabric shifted when I sewed those triangles together. I can’t square this up or trim it anymore because I don’t have any extra fabric. When I sew this piece to another piece, I will probably have difficulty matching the points of the triangles.

Here’s the set that I added an inch to the finished size. I didn’t sew this very well either. You can that up here in the corner. I hate to admit it - when I sew triangles together, I am often off a little. That’s why I like to get this extra cushion by adding that 1 inch to the finished size. Even though this is not lining up right now, I think I will be able to square it up to a perfect 2 ½” square.

Whenever I square up I always want to remember that I have to keep an eye on that diagonal. So that’s the first thing I want to do. Take the diagonal line on my ruler and line it up with the diagonal line on this square. I’m going to be cutting 2 ½ inches. The 2 ½ inch mark – 1, 2 and ½ - is right here. And when I come across – 1, 2 and ½ - so I’ve got extra fabric here, extra fabric on the bottom, a little on the side and a little extra at top. My diagonal is lined up so I am ready to cut.

Let’s turn that around now and make our final cut. The first thing I want to do is line up that diagonal. So here we go. I have the diagonal on top of my fabric’s diagonal. I’m looking at the 2 ½ inch mark. I see that I’m going to have to come over a little bit. Let me cut. I cut across and I have a 2 ½ inch square where that diagonal line goes straight across.

You can find more information about cutting and sewing half square triangles at LearnHowToQuilt.com under “Beginner Basics” – “Cutting” and “Sewing”.

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