How to square up HST of any size using a Bloc-Loc Ruler

For September's instructions in the Foothill Mystery Quilt, we had to make 144 half square triangles (HST).  I received a few questions from quilters on how I trim my HST using a Bloc-Loc ruler so I thought I would post a quick tutorial on how I use the Bloc-Loc ruler to quickly and easily square up my HST.

First, a little note that Bloc-Loc is in no way sponsoring this post.  I am not one to typically buy specialty rulers, but if you like making a bunch of HSTs, I would totally suggest getting a Bloc-Loc ruler.  The ruler has a groove cut into its back that the seam of the HST rides along to ensure that the corners of the triangles meet right at the corner of the HST.

I have the 6.5" HST Bloc-Loc ruler and it allows me to trim a HST of any size up to 6.5" square.  To work with this ruler, the seam must be pressed to the side.  I also use a rotating cutting board, this is not necessary but very helpful to speed things up.

For this tutorial we will be trimming a HST to 4" square and in the HST shown below, the seam is pressed towards the pink gingham print.

To begin, place the Bloc-Loc ruler on the HST such that the groove rides along the seam (Bloc-Loc logo will be right side up and the seam will be pressed downward) and trim a little off of the HST to create two straight edges.

Next, either rotate the HST or the cutting board (if it is a rotating board) 180 degrees leaving the Bloc-Loc ruler in place on the HST. The Bloc-Loc logo will now be upside down.

Next, align the nicely trimmed corner of the HST to the 4" mark on the Bloc-Loc ruler and trim the excess.

The HST is now beautifully trimmed with the corners of the triangles lining up perfectly with the corners of the HST.  Go make a couple hundred :)

Thanks for reading my tutorial!  If anything is unclear or you have any questions, please leave a comment or e-mail me.

I am linking up to MOP Monday @ Tweety Loves Quilting, Anything Goes Mondays @ Stitch by Stitch, Fabric Tuesday @ Quilt Story, and Sew Cute Tuesday @ Blossom Heart Quilts, and Show and Tuesday @ Freshly Squeezed Fabrics.