Lubrication pointsmust receive daily attention during the season. Follow the lubrication schedule given in the operator's handbook. Some self-propelled harvesters have central lubrication banks with groups of conveniently placed grease points connected to the more inaccessible bearings. Gearbox oil levels and tyre pressures should be checked regularly. Belt and chain drives must be correctly tensioned.
Figure 15.4 Knife sharpening mechanism. (New Holland)
Cutting flails,used on some harvesters, must be sharp and secure. Any missing or badly damaged flails must be replaced immediately to avoid rotor vibration. Flails should always be replaced in opposite pairs to maintain correct rotor balance. Nuts and bolts, especially on components which run at high speed, must be kept tight. Keep all cutting edges sharp: blunt knives give inferior results and waste power.
Plate 15.9 Loading grass onto a silage clamp using a buckrake on a 112 kW (150 hp)
wheeled loader. (JCB)
Knife sharpeningMany flywheel and cylinder chop mechanisms have a built-in knife sharpener. A grinding stone is attached to guide rails which are set parallel to the edge of the knives. The cylinder is turned slowly under power and the stone is drawn across the knives by a hydraulic ram. On some machines this procedure is controlled from the cab; on older models the stone may be moved across the guide rails by hand.
The shearbar must also be sharpened from time to time to ensure a clean cut. The clearance between the shearbar and the knives is critical. This is usually a manual adjustment but some self-propelled harvesters have a small electric motor, controlled from the cab, to adjust shear-bar clearance.