The Creative Grids 9" Seam Guide Tool is such a simple and inexpensive tool, and just perfect for marking Half-Square triangles! Not only do you mark the center line for cutting your HSTs, but you actually mark both stitching lines for sewing your Half Square Triangles. This means that your half-square triangles are more accurate when stitched! You'll love how easy it is to make accurate half-square triangles with the Creative Grids 9" Seam Guide tool!
Get the Creative Grids Seam Guide shown in the video in my shop here: https://carolinamoorepatterns.com/products/creative-grids-9-inch-seam-guide-tool
Get the Creative Grids Seam Guide at the Fat Quarter Shop (affiliate link): http://shrsl.com/3bqd6
Here are affiliate links to the items that I use in my sewing room:
Creative Grids Rulers - http://shrsl.com/354lk
Baby Lock Jubilant - http://shrsl.com/354lh
Baby Lock Aria Dealer List - https://babylock.com/retail-locator
Art Gallery Fabrics - http://shrsl.com/354lg
Oliso Iron - https://www.oliso.com?aff=17