I used to be intimated to sew with triangles, but after learning some helpful techniques and with some practice, it really isn’t too hard! In this article I will show you how to cut equilateral, or 60° triangles, using a quilting ruler and rotary blade – it makes cutting the triangles super easy! I also share tips for accurately sewing the triangles together that can then be used for so many different sewing projects!
I used my pieced together triangles that I later quilted to a layer of batting to make a super cute quilted zipper pouch. You can see how in my tutorial How To Sew a Lined Zipper Pouch. My bag pattern the Edgewood Sling Bag would be a great project to make with this quilted triangle design!
Let’s get started!
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Some Things You’ll Need
- Quilting ruler – My favorite ruler! It doesn’t have to be this exact one, but it should have degree measurements on it.
- Rotary blade
- Cutting mat
- Fabric – Quilting cotton is easiest to work with, but linen can also be used.
If you need an extra visual, then you can watch the YouTube video tutorial (below) or keep reading for the full written steps!
Prepare Fabric Strips
First you’ll want to cut your fabric strips. The width of the strips will determine the size of your triangles – I’ve cut 3″ wide strips which make the finished triangles a scant 3 1/2″ on each side. *The sides will be a longer measurement than the strips since they’re cut on an angle.
The length of the strips is up to you and dependent on your project. I’m making a zipper pouch with these pieced triangles so I didn’t need very long strips. Let’s say you need a lot of triangles for a quilt – you can fold your fabric together selvage to selvage and cut the strips from the fold to the selvage edge.
Cut Out Triangles
Lay the fabric strip so the selvages are at the right. If you’re working with long strips you can keep the fabric folded in order to cut two at a time.
Orient the quilting ruler so that the 60 degree line is lined up along the bottom of the strip (see photo above).
Holding the ruler firmly in place, cut along the edge of the ruler. You’ve made the first 60° angled side!
Turn the strip over (if the fabric has a definite wrong and right side, the wrong side will be facing up) so that the angled edge is on the left and angling up to the right (see photo above).
Line up the ruler again with the 60° line along the bottom edge of the strip. The ruler that I’m using also has two lines that cross in the middle, so I can line up the point of the triangle in the 60° corner on the ruler – very handy!
Cut along the edge of the ruler, and you have the first triangle! (Or the first two, if your fabric strip was folded in half).
Turn the fabric strip over again so the angled edge is on the left and angling up to the right and line up the ruler along the 60° line at the bottom. By turning over the strip of fabric, it means you don’t have to keep adjusting or rotating the ruler.
Continue cutting out triangles in this way until you reach the end of the strip or have the desired amount in that fabric.
Sew Triangles Together
Before sewing the triangles together, lay them out and plan out your design. Once my design is final, I like to take a picture to remember it or in case it gets messed up somehow. Since I was making a zipper pouch with the quilted pieces I measured it up against the zipper length I was using to decide how many triangles I needed in each row.
*Keep in mind that the left and right edges will eventually be straightened and the triangles at the end will be cut in half. You’ll see more what I mean on a later step.
Take the first two triangles at the beginning of the first row and pin them right sides together. Sew along the pinned edge with a scant 1/4″ (0.6 cm) seam allowance.
*In quilting, it’s common to sew with a scant 1/4″ seam allowance which helps achieve accurate seams.
Press the two triangles with the seams towards one direction. You will noticed that there is a bit sticking out at the ends – that’s ok! From here, you can can either sew each triangle on individually or sew them together in pairs by chain piecing.
Chain piecing is a quick and efficient way to piece together a lot of fabric shapes. All you do is, after sewing the first pair, continue sewing without lifting the presser foot and sew right onto the next pair. You end up with a garland of triangles which you can cut apart in between the pairs after sewing.
Once you have your triangle pairs sewn together, press them with the seam allowances going in one direction. I like to press each pair in the same direction in one row and then the opposite direction in the next row.
When lining up the triangles to sew, line them up from point to point (see photo above). You may need to unfold the pressed seam allowances to get it lined up, but then place the seam allowance back where it was.
The tip of the triangle will stick out (at either the top or the bottom) but thats ok! Pin together two triangle pairs and sew with a scant 1/4″ (0.6 cm) seam allowance.
Keep adding triangle pairs until the row is the desired length and press flat.
Since my rows were made up of an odd number of triangles, I needed to add a single triangle at the end after sewing all the pairs together. Remember to line up the points of the triangles and sew with a scant 1/4″ (0.6 cm) seam allowance (see photos above).
Sew Rows Together
Once you have all your triangles sewn up in rows, it’s time to sew the rows together!
Place the rows right sides together, lining up the raw end and matching up the points of the triangles together throughout the row and at each end.
Pin the rows together using plenty of pins to make sure everything lines up well. I like to place a pin right at the tip of the triangle stitch line.
Sew the rows together with a scant 1/4″ (0.6 cm) seam allowance. While sewing, make sure to not sew through the points of the triangles.
Press the two rows flat with the seam allowances going in one direction. Continue to sew rows together in this way until you reach the desired size for your project!
Since I’m making a zipper pouch, I only needed three rows with 7 triangles in each row.
Trim off Edges
If you’re making something square or rectangular, like a quilt, pillow or zipper pouch, you will need to cut off the edges to the dimension you need.
I’m using a 8″ (20.3 cm) zipper and the total length of the zipper is about 8.5″ (21.6 cm). It worked out pretty well that my rows ended up just about the same length as the zipper. 🙂
Since I’m using 1/4″ (0.6 cm) seam allowances for my zipper pouch, I included that amount before cutting by using the bit of seam allowance sticking out at the top as a guide (see photo above).
Cut off each side of the pieced triangles using a ruler and rotary blade, making sure to keep everything straight.
Then, using the ends you just cut as a guide, cut off the bits on the other sides to finish squaring up the rectangle. For reference, my finished rectangle ended up being 8 5/8″ wide and 7 1/4″ ( 21.9 cm x 18.4 cm) tall. Then I quilted a layer of batting to the wrong side and used it as my outer fabric for my lined zipper pouch!
And you’re done!
I hope this tutorial was helpful and gave you some confidence to sew with equilateral triangles! Thanks for reading and happy sewing 🙂