Aurifil 50wt Cotton Mako 6452 Spool - 1246 - DARK GREY . Aurifil 50 weight thread is the most popular thread for quilters. It is 100% Cotton Mako thread and can be used for machine piecing quilts, hand piecing quilts, machine applique, hand needle turned applique, fine needlework, foundation piecing, miniature patchwork, detailed quilting, bobbin lace making and machine embroidery.