Equilateral Triangles : Starter Block (Cutting)






I think that Equilateral Triangles are the perfect choice to feature this month for the A Year of Traditional Blocks series.  I know that some of you don’t consider these a “traditional” block shape but they were one of the first patterns that I ever learned when I started studying quilt blocks, only under a different name.

Thousand Pyramids is how I know the traditional equilateral triangle quilt. A little research dated this pattern to 1929. Depending on fabric selections, an equilateral triangle quilt has also been referenced under the names: Red Shields and Pyramids. 

Whatever name you know it under, equilateral triangle quilts have a ton of design potential but the shape can be intimating to some quilters (all those points!).

For this month’s Starter Block, I’m breaking the posts down into two sections: Cutting and Piecing. This is so I can include a lot of photos and helpful tips without worrying about cramming it all into one page space.

Today’s focus is Cutting…WITHOUT a specialty ruler!

I’m including two options:

  • Cutting using a 60° guideline on a ruler
  • Cutting using a 60° guideline on a cutting mat (for rulers without angle lines)

For either option you’re going to want to start with a strip of fabric. The width of this fabric is determined by how TALL you want your triangles to be.

I’ve chosen 4.5″ for mine:


Option One: Using the 60° Line on a Ruler: 

Obviously, for this method you need your large straight edge ruler (6″ x 24″) to have 60° marked on it. I’ve run a piece of washi tape underneath the line on mine so that it’s easier to see in the photos.


To start your triangle cuts, align the 60° mark with the BOTTOM edge of your strip, placing the point of your ruler at the corner:


Cut the first angled edge, the piece you cut off can go off into the scrap bin:

Without moving the fabric, flip your ruler over to the wrong side (I’ve used a different type of washi tape to easily distinguish between the back and the front of the ruler). You can see in the picture below that my numbers are backwards, but this also means that my 60° line is going in the opposite direction. Align the 60° line with the TOP edge of your strip, the point of the ruler will be in the top corner now and cut along the ruler’s edge:


Continue to flip your ruler along the strip, alternating between aligning the 60° line with the top and bottom of your  fabric strip:


I will say here that this is my preferred method to cut equilateral triangles. I like not moving my fabric and after a couple of minutes I can settle into a natural rhythm of flipping the ruler.

But I’ve found while teaching classes that not everyone’s favorite ruler has that 60° line on it so the next option uses the line on your mat instead.

Option Two: Using the 60° Line on your Cutting Mat: 

For this option you can use any long straight-edged ruler that you’d like. Your reference line will be the 60° line on your cutting mat:


To start you’ll need to align the corner edge of your fabric strip with the 60° line on the mat. I like to set my fabric somewhere where the 60° line intersects with one of the inch lines. Set your ruler along the 60° line and cut your first angle:


My mat doesn’t have two sets of 60° lines that cross so we need to flip the fabric in order to get an angle going in the opposite direction. Turn your fabric strip so that it is WRONG side up. Set the bottom corner on the 60° guideline. Align your ruler with the guideline and cut:


Here’s your first triangle:

Flip your fabric back to the RIGHT side up. Again, the bottom corner gets set touching the 60° guideline.


Place your ruler along the 60° guideline and cut.

Repeat these steps above until you reach the end of your fabric strip.


Both of these cutting options work with strips of any width which is one reason I prefer to cut this way. A lot of times I’ll work on projects that mix different heights of triangles together but I never have to worry about changing lines on a specialty ruler.

I’ll be back on Monday with my tips for piecing equilateral triangles. If you have any questions, send them my way and I’ll work them into the post (or reply by email if it’s lengthy).


One Response to Equilateral Triangles : Starter Block (Cutting)

  1. Jeifner June 8, 2014 at 5:23 am #

    Looking good! I’d like to do a triangle quilt.