Grandma would have loved a rotary cutter! Grandma would have loved a speedy sewing machine with a 1/4" guide on the foot, a self-threader, and a push button that clips the threads. Grandma would have loved my longarm quilting machine. I can sometimes picture all the grandmas looking over my shoulder as I quilt.
They would have loved today's TOOL: Quilt in a Day's Triangle Square-Up Ruler by Eleanor Burns.
Basically you stitch two triangles together, and while still folded, align the ruler over your stitches, then trim the excess.
ALIGN ruler over stitches.
Open and PRESS.
Makes beautiful, perfect half square triangles. Love those corners!
I love it for squaring up quarter-squares / hourglass blocks too.
Ohio Star - my favorite block!
HST = FS + .875I just round up and add 1" to 1-1/8" instead, then trim. (By the way, I compiled all these math formulas into my handy Quilter's Bible << available here.)
And the answer is YES. I always trim each unit, no matter how perfect my measuring/cutting/piecing techniques. I can't help it - I'm a little OCD, and pointy points take me to my happy place. *Ü*