Half-Square Triangle Block Tutorial

Categories: Bedding, Quilts

What you need to make this project

The photographed quilt using Nature-Fil Bamboo @ Natural Cotton Batting
2 or more contrasting cotton quilting fabrics
Marking pencil
Rotary cutter and mat or sharp scissors
Sewing machine
Coordinating thread

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Nature-Fil™ Bamboo & Natural Cotton Blend Batting 45″ wide x 10 yard Bolt


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Step One

****Note the full free pattern for the Flower Garden Weekend Quilt shown in the photographs can be found here.

Flower Garden Quilt

Let your pattern determine the size squares you start with.  As a general rule, you’ll want to cut your squares 1/2 inch BIGGER than you want your finished Half-Square Triangles blocks because you’ll loose some to trimming and seam allowances.  The quilt I was making used the same two fabrics in all of the half-square triangle blocks, so I cut out equal numbers of my two fabrics.

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Step Two


Layer your two squares on top of each other with RIGHT SIDES TOGETHER.  Carefully line your quilting ruler up on the diagonal.

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Step Three

Mark with your pencil.

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Step Four

Carefully pin your squares together with the pins going through the fabric on either side of the line you drew, making a right angle with your line.

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Step Five

If your fabric has an up and down direction like one of mine did, you’ll want to make sure that you alternate which diagonal you draw the line through.

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Step Six




Stitch with a 1/4 inch seam allowance on EACH SIDE of the line you drew.  DO NOT stitch on the line itself.  When you’re done, you should have TWO seams going through your square.

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Step Seven

Use your rotary cutting or scissors to carefully cut through your marked line.  Each set of squares you sewed will yield 2 Half-Square Triangle Blocks.

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Step Eight

Different quilters have different opinions about whether to press your seams open or press your seams to the side.  I prefer to press them open.  Iron well.

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Step Nine

You may be anxious to use your squares, but if you want your corners to match up properly, you really need to trim up your squares, so they are exactly the size you need.  Most quilting rulers have a 45 degree line marked.  Line up your 45 degree marking with your diagonal seam, so that they line up exactly.  Trim your square.

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Step Ten

And now you’re ready to add these blocks to your chosen quilt pattern.