Friday Quilt Class: What is an HST?

The Half Square Triangle

When I first started quilting, I would

hear people talk about HST's, I had no

idea what they were.  When I asked about

them I was told they are half square

triangles ~ but again, I had no idea what

they were...

A half square triangle is a unit in a quilt

block that is made up of 2 triangles of

different fabrics.  When I come across

 patterns that have you make an HST

 by cutting triangles and sewing them

 together along the wonky, bias seam,

I always stop and convert the pattern to

this method of making HST's.  It is much

more precise this way.

Today we will be working with a 3"

finished square, so by adding our

seam allowances our square will

be 3 1/2" unfinished.  To make the

HST we will add 3/4" to our

measurement and cut 2 squares at 4 1/4".

On the back of the lighter fabric we

will mark a diagonal line.  I do this by

placing a pencil point at the top of the

diamond shape.  Then I put my ruler

up alongside the pencil, using my left

hand, I can pivot the ruler until it is in

the proper place to mark the diagonal

line with my right hand.

This is what the drawn line should

look like.  Now place the 2 fabrics

right sides together.

Sew 1/4" away from each side of drawn

line.  I find if I run the guide on my 1/4"

seam foot along the drawn line it works

out perfectly.

Cut apart on drawn line.

Generally you should press the

seam toward the darker fabric.

This is not always true though, we

will go over that when we get to

the "Pressing for Piecing Precision"

tutorial in the future.

Next you will square up in two steps.

Step One is to place the diagonal line

on your ruler along the diagonal seam

on your block and trim about 1/8" from

the top and and right side.

For Step Two, remove the ruler and turn

the square so that the upper right hand

corner that you just trimmed is now in

the lower left hand corner.  Place the ruler

back on the square and line up the left

and bottom edges along the 3 1/2"

guidelines on your ruler and trim the

upper and right side edges.

For each unit that you make you

will end up with 2 HST's.

The Half Square Triangle is one

of the major building blocks for

a quilt.  Once you master this

technique you are well on your way

to making precise quilts.