TeresaA

For me, it basically means you want to make the seam small enough that the tiny width of the row of stitches used to make up the seam doesn't add to it, that seam thread bulk = 1/4. On my old Pfaff it took a good 1/4 inch foot to achieve it. People will chime in with other tips. I found the customary ones difficult with my eyesight. The only thing that really helped to achieve this was the foot.