20 Ways to Make HSTs – Using Strips

Making HSTs using Fabric Strips

Half square triangle units (HSTs) are squares made up of two triangles. Each triangle occupies half of the square’s space. As you might expect, there are many, many different methods to make those blocks. This tutorial shows you 20 of the most common methods.

First, a glossary.

A finished HST is the size that it is in a quilt. It’s dressed and ready to go to the ball. An unfinished HST is in raw, unclothed form. It will be 1/2″ larger than a finished HST because the size includes a 1/4″ seam allowance.

Rulers that Cut Triangles from Strips

Easy Angle Ruler, Omnigrid 96 Ruler, Creative Grid 4590 Ruler

Easy Angle shows how to cut the triangles with blunted edges so they match up perfectly, as does the Omnigrid 98L both of which cut QSTs as well. Strips are cut 1/2″ larger than the size of the finished HST. Lay the ruler so the line for the finished size is on the bottom of the strip. It will go over the top.

These rulers use strips the size of the finished block to cut the triangles for an HST block. Just layer a light and dark strip right sides together and use the ruler to cut out triangles. Lay it over a strip of fabric (matching the line on the ruler) to cut your first triangle. The graphic shows the Easy Angle ruler, but they all work the same way.

Then flip it to cut the second triangle. The numbers along the side of the ruler give the size of the HST you will make using each of the strip sizes shown. The 1/4″ seam allowance is built in.

For example, to make 2 1/2″ HSTs, you would use the 2″ line. Because of the blunt end on the ruler, your triangles will already have the “dog ear” cut off. This makes them easier to feed through the machine as the tiny triangle point doesn’t get caught in the feed dogs.

Pam R was kind enough to make these examples for me. She even shows how to use a Bloc-Loc to square up the block!

Creative Grids CGRMS4590 is a dual-purpose ruler that cuts half-square triangles and quarter-square triangles. Use the 45° side to cut half-square triangles from fabric strips. Turn it around to cut 90° triangles for Quarter Square Triangle blocks. Here is a video.