Machines of Class 16, described in this book, each have one needle and a central bobbin, oscillating shuffle and make the lock stitch. Machine 16-81 is especially designed for book and pamphlet, stitching. It makes stitches from 1/4 to 15/16 inch in length and will stitch a book or pamphlet, up to 3/16 inch in thickness. It has a drop feed and a roller presser.