I sew Y seams without marking the blocks for a start and stop point. Most of us have an idea of a quarter inch seam allowance and I don`t think the marking the stop or start point is necessary. You will save a lot of time by not marking.

Sewing patches and sewing blocks

Start the seam at the outside edge when joining patches. When joining blocks, start in 1/4 inch Stitch seam to 1/4 inch of end at intersection or end of seam. Stop, break thread and open patches, finger press seam to one side. Generally to the darker side or away from start of next seam. Add third patch and again you can sew from outside edge to 1/4 inch from center. You can use your nail to scratch a line on the top patch to mark the 1/4 inch spot which is the stopping spot. Break the Thread. Flip the top patch to with right side to the next patch. Flip the seam allowance out of the way and sew from center out.

Sewing Blocks together. When joining blocks, you will need to leave a 1/4 inch open at the beginning and end of the seam. The procedure is the same Conjoining blocks as it is for patches.

Internet sites that provide demonstrations for Y seam blocks

WWW.Freshlemonsquilts.com/?p=1373   Fresh Lemons - Y-seams Tutorial

www.quilt-video.com/2009/02/l3/perfect-y-seams-with-kaye-wood/  She shows doing the seam without breaking the thread.

bloominworkshop.wordpress.com/2011/10/30/the-secret-to-y-seams