Machines of Class 11 have a cylinder bed and a drop feed, and are especially designed for stitching heavy tubular shaped articles in cloth or leather. They are used in the manufacture of mail bags, coal bags, ore bags, military boots and a great variety of similar articles. Some of the machines of Class 11 are intended for making grommet holes and overseaming or zig-zag stitching in heavy fabrics. Machines 11-34 and 11-35 are equipped with the “SINGER” Driving Attachment, otherwise they are the same as Machines 11-29 and 11-17 respectively.