Originally Posted by
quiltmom04
I have found thorough trial and error that thread size does affect the seam allowance. So I try to use the same thread throughout the piecing. With "So Fine" from Superior Threads, my seams are more true to 1/4" . With Connecting threads thread, I have to allow almost 1/16" to account for the width of the thread. Finished block size, I like to stay within 1/8" of what it's supposed to be, and I try ( notice I said TRY) to be extremely accurate when star points are right on the seam line. If they aren't quite to the seam line, I can live with it, but if they are chopped off, it really bothers me.
Same here, I stopped using Connecting Threads cotton thread for piecing and am using up cones of polyester serger thread. I have tons of it from when I used to sew for the public. It used to be the elusive quilt police frowned on using polyester thread on cotton quilt fabric, but once I realized it was okay, I've been using ever since. It DOES seem to make a difference because the thread is thinner.
My Brother Dreamweaver allows me to change the needle positions in increments as small as 1/8 of a millimeter, but the seam will only be accurate if I follow the guide precisely. I have to have an additional guide besides just the edge of the foot or the edges of my patches will tend to wander under the foot and loose a nanometer or two in the stitching. I especially tend to wander off when sewing HSTs and other pointy-ended patches.