23 COMMERCIAL SEWING MACHINES; DARNING, EMBROIDERY, ARTICLE FASTENING, HEMSTITCHING, BUTTONHOLE MAKING, EYELETING, AND ORNAMENTAL STITCHING MACHINES; BOBBIN WINDING, STRIP CUTTING, PRESSING, STRIP WINDING, TRIMMING, PLEATING AND GRINDING MACHINES; SEWING MACHINE NEEDLES; AIR BLOWING APPARATUS EMPLOYED FOR SEWING MACHINE NEEDLE COOLING AND LINT-DISPERSING; LOOP-FORMING IMPLEMENTS IN THE FORM OF GUIDES ABOUT WHICH THREADS AND YARN MAY BE LOOPED BEFORE STITCHING SAME, BELT PUNCHES, HONING DEVICES FOR SHARPENING KNIVES AND BLADES, BELT TIGHTENERS FOR TAKING THE SLACK OUT OF POWER TRANSMISSION BELTS, SCISSORS, PINKING SHEARS, WRENCHES, BELT HOOKS FOR SECURING TOGETHER THE ENDS OF POWER TRANSMISSION BELTING, SCREW DRIVERS, HAND AND POWER OPERATED CLOTH PINKING MACHINES, C-CLAMPS, CLOTH GRIPPERS FOR SECURING A WORK-PIECE TO OR UPON A TABLE, WORK-HOLDING IMPLEMENTS FOR MAINTAINING A WORK-PIECE IN OPERATIVE RELATION WITH A SEWING MACHINE CUTTER BLADES, FINGER GUARDS IN THE FORM OF WIRE OR GLASS SCREENS TO PREVENT AN OPERATOR'S FINGERS FROM ENGAGING A MOVING MACHINE ELEMENT, THREAD LUBRICATORS IN THE FORM OF GLASS OR METAL RECEPTACLES ADAPTED FOR CONTAINING A THREAD LUBRICANT, STILETTOS, TWEEZERS FOR SEWING USE, AND SEAM RIPPERS IN THE FORM OF A KNIFE; STOCKING DARNERS IN THE FORM OF A MATERIAL SUPPORTING FRAME FOR PRESENTING MATERIAL TO A SEWING MACHINE, AND FAGOTING UNITS ABOUT WHICH CORDS MAY BE WOUND BEFORE STITCHING SAME; SEWING MACHINE ATTACHMENTS-NAMELY, EMBROIDERY, EDGE STITCHING, MULTIPLE SLOTTED BINDER, BLIND STITCH, ZIGZAG, HEMSTITCHING, BUTTONHOLER, BINDING, GATHERING, HEMMING, RUFFLING, BRAIDING, BLIND-STITCH BRAIDING, FLANGE HEMMING, QUILTING, SHIRRING PLATE, TUBULAR TRIMMING, TUCKING, CORDING, ZIPPER FOOT, DARNING FOOT, UNDERBRAIDING, BIAS GAUGE, CLOTH GUIDING, BIAS BINDING, SCROLL HEMMING, ORNAMENTAL STITCHING, AND THREAD-CHAIN CUTTING ATTACHMENTS; SEWING MACHINE POWER TABLES AND STANDS; FITTED CANVAS AND BENT WOODEN COVERS, AND PORTABLE CARRYING CASES FOR SEWING MACHINES; AND GREASE GUNS; AND PARTS THEREOF