Hi. Noticed your fraying problem.Since it's a king-size quilt you are working on and it may take some time to finish, I'd run a row of machine stitchs along that top. Then if you're still worried, machine baste a piece of material up there until you're done with the quilt.A piece of old sheet would work fine for that. Better the extra work now than to not have enough seam later. D'Marie