Abstract: A spacer spool for a disc section of a disc harrow for preventing relative rotation between the spacer spools and the adjacent disc blades. Each of the spacer spools comprises a central portion having end portions extending outwardly from the opposite ends thereof. Each of the end portions is provided with an annular rim portion which is complimentary in shape to the adjacent disc blade. The center section of the spool is provided with a central opening for receiving an elongated shaft which is rotatably supported by the disc harrow frame. A lug is provided on each of the end portions of the spacer spool between the central opening and the annular rim portion. Each of the disc blades has a central opening formed therein for receiving the shaft and has a bolt opening formed therein spaced outwardly from the central opening. A bolt is positioned in each of the bolt openings and has its head positioned adjacent one side of the disc blade and a nut element positioned adjacent the other side of the disc blade.

Abstract: A replaceable tool for attachment to the periphery of an agricultural disc is formed of an inverted U-shaped investment casting which can be fitted over the marginal edge portion of the disc to present parallel leading and trailing faces connecting side surfaces which converge outwardly of the disc, being inclined at different angles relative to the plane of the disc so as to present on one side of said disc a side surface providing clearance for the disc on that side of the disc and the other side surface being at a greater angle which reduces the areas of the end faces of the tool to reduce resistance to passage of the tool through the ground.

Abstract: In order to overcome the limitations on availability of suitable steel strip or bars in widths to suit all diameters of agricultural discs, a method of manufacturing such discs comprises cutting blanks from rolled steel strip or bar having a thickness greater than the thickness of the finished discs and a width less than the diameter of the finished disc, the blanks having a length substantially equal to the diameter of the finished discs, rolling each blank in the direction of its width until that dimension has increased to not less than the diameter of the finished discs, and blanking out from each rolled blank a disc with a diameter not less than the diameter of the finished discs and with a central hole, the cross-rolling of the strip or bar necessary to achieve the required increase in width and reduction in thickness having the beneficial result in affording quality comparable with that of discs formed from cross-rolled plate or sheet.