Round file holder for a chain saw sharpener

An improved round file holder for various diameter files for use in conjunction with a chain saw filing guide for sharpening chain saws comprising

• a pair of identical longitudinal stringers formed of integral pieces of bent and punched sheet metal and having extended flat body portions juxtaposed in mirror image facing relation with opposed edges facing each other and with outer edges which can be engaged with a filing guide designed for mounting on a chain saw cutter bar and saw chain whereby said file holder can be reciprocated in said guide at a preset angulation with respect to said cutter bar and chain to sharpen the teeth of said chain, said stringer body portion along the opposed edges being cut away toward said outer edges between the ends of said stringers except for a portion along the opposed edges proximate the center thereof,
• a first pair of vertically upward projecting tabs disposed on the opposed edges of said stringers proximate each of the ends thereof and formed for accepting a fastening means for securing the stringers together, said tabs being formed by bending ears formed on said sheet metal body portion upward at 90.degree. with respect to said body portion, one of said tabs of each pair including a projecting bearing surface disposed at the upper end thereof for contacting the opposing tab above the position of the fastening means which extends between the tabs for securing the stringers together whereby each pair of opposing tabs are separated a finite distance by said bearing surfaces, said body portion of the stringer at the juncture where said first tabs are bent upward 90.degree. therefrom forming the contact surfaces for the file against the holder,
• guide rails formed on the outer edges of said stringers for engaging said filing guide and permitting reciprocation therein in captured relation to provide accurate tracking of a file secured in said holder with respect to said guide and any saw chain and cutter bar it is mounted on, said guide rails being formed of a flat flange of uniform height which extends for the length of said stringers disposed at 90.degree. with respect to the body portion thereof, said guide rails being formed by bending a flat straight edge of said stringer at right angles to the body portion thereof,
• a second pair of tabs disposed at opposite ends of said stringers adjacent to each said first pair of tabs and projecting downward from the body portion of said stringers in the opposite direction from said first pair of tabs, said second tabs being angled approximately 45.degree. with respect to the main body portion of said stringers whereby a round file is captured between the second pair of tabs and the body portion of said stringers at the ends thereof when the two stringers of the file holder are secured together by the fastening means, said second tabs being formed on each said stringer by bending a portion of each end of the sheet metal stringer downward from said body portion of said stringer, and
• an adjustable fastening means for securing said first tabs together with an adjustable connection whereby the opposing edges of the stringers can be angulated toward and away from each other pivoting on said bearing surfaces whereby different diameter round files can be accommodated by and secured in said file holder, said fastening means including a nut and bolt which can be adjusted to accommodate different diameter round files.