Originally Posted by
margecam52
I have tried a lot of different feet, the plastic template for diagonals, etc. I'm back to my clear foot with red markings..I use that and have marked a scant 1/4" line & a center line with a sharpie from the very back of the machine bed, to the very front...these I covered with clear tape to keep it from rubbing off. Works for me. I can do the diagonal stitching to make half square triangles, etc. & have a constant seam allowance. I've marked this on all three of my domestic machines, using the same template for all of them...I took an index card, measured over the scant 1/4" and put the needle into the card to mark my spot. The lines on an index card are 1/4"...so my needle is just to the right of one of the lines in the card. I also marked the centers that way...putting the needle right in the line on the card...marked the front spot and a back spot...raised the needle and using the card...lined it up and used it as a "ruler" to mark the back to front (omitting the face plate). I also used the card with the needle in the scant 1/4" to mark the line for that back to front. No special tools needed.
All that works fine if what you want is a perfect
seam allowance. What really matters is the measurement
between the seams and that will change due to thread weight, fabric weight, and pressing changes even though your seam allowance remains rigidly at ¼".
I do a three 1½" strip test with every change of fabric/thread combo to make sure the middle strip comes out at a 1" finished width and adjust my seam allowance to get that result. I change fabric and thread combos way too often to ever put permanent lines on my machine beds and don't even want to think about what that would do to resale or trade values of the machines. I'm glad it works well for you though.