30 - Equilateral Triangles

Tutorial for a 12 inch Equilateral Triangle Block

Ahhh...I enjoyed making this block much more than the apple core block.  Triangle quilts have been popping up all over blogland recently.  In fact there is even a Patchwork Prism QAL starting up that uses equilateral triangles -- I may just have to join in.

An equilateral triangle quilt, by Constança Cabral via flickr

Before we get to the block, let's review some basic geometry.  A triangle has three sides.  So far so good.  ;)  An equilateral triangle has three equal sides and three equal angles.  All of the angles on a triangle add up to 180 degrees.  Since each of the three triangles on an equilateral triangle are equal, the corner angle can be determined by dividing 180 by 3.  180/3=60  Each angle in a equilateral triangle is 60 degrees.

An example of an isosceles triangle quilt by Audrie of Blue is Bleu via flickr

An isosceles triangle has two sides and two angles that are the same.  The third side can be either shorter than the other two (like the quilt above) or wider like a half square triangle.  A half square triangle is both a right triangle and an isosceles triangle, for those who want to go the extra geometric mile.  Check out this site for more fun triangle facts.

Template

The first step to make this block is to make a template.   You can cut the triangles without a template, but it involves a lot of thinking and moving your ruler around to find the right angle.  A template is much easier.

Cut a piece of paper or card stock 3.75 inches tall.  The quilt math rule for equilateral triangles is that the unfinished triangle needs to be cut 3/4 inch taller than the desired finished size.   Our finished triangles will be 3 inches tall.

Next identify the 60 degree marking lines on your ruler.  Also remember that the other side of the 30 degree line is 60 degrees.  How do we know that?  The ruler has 90 degree angles in each corners.  90 degrees minus 30 degrees equals 60 degrees.  Still doesn't make any sense?  Just trust me and know that you might have to use your 30 degree angle to make the template.

Cut one side of the template off at a 60 degree angle (you might have to line it up with the opposite side of the 30 degree mark for the ruler to be long enough to make the cut).  Next line up the 60 degree line with the cut angle and make a second cut.  This is the template.

I find it easiest to use the template when it is attached to the back of the ruler.  Tape the template to the back of your ruler with one of the sides along the edge.

Cutting

Cut a strip of fabric 3.75 inches wide.  Line up the bottom of the template with the bottom of the strip of fabric with the ruler edge facing the end of the fabric strip.  Cut.

Turn the ruler and line up the bottom and left edge of the template with the bottom and left edge of the fabric.  Cut.  Continue cutting all the way down the strip of fabric.  Cut a total of 32 triangles.  I cut 16 white triangles and 16 blue triangles out of various fabrics.

Arrange the triangles as desired in four rows of eight triangles.

Sewing

Sew each row together.  Place the first two triangles in the row right sides together and sew down the side with a 1/4 inch seam.

Next open up the triangle and lay the next triangle next to it.  Flip the third triangle on top of the other two.

Line up the corners of the triangles and make sure the seam is off to the side.  Sew with a 1/4 inch seam.

Keep adding triangles until you have sewn all six together.  Repeat for each row.

Press seams very carefully to the side.  The sides of the triangles are cut on the bias and will stretch very easily.  However, this can work in our favor.  If your rows are slightly bowed give the row the tiniest of pulls as you press to straighten it.

Use a ruler and rotary cutter to cut off the dog ears.

 Sew the four rows together pinning at the seam intersections.  Then trim the sides of the block so that the block is 12.5 inches wide.

You did it!  

How did you like it?  Have you made a triangle quilt before?