Home Making

Lawn Mowers

WHATEVER the type or make of lawn mower there are general directions which must be observed, in the interests of the operator, the lawn, and the machine. The most obvious precaution is, perhaps, most often neglected: the clearing of the lawn of stones and other small rubbish before mowing commences. The knives of a machine rotate at great speed, and it needs only the introduction of a small stone, or nail, between the knives and the bottom blade (which between them do the cutting) to damage the mower.

The counsel of perfection, therefore, is that the lawn should be swept each time before the mower gets to work. The alternative is for the operator to inspect the grass closely, walking methodically up and down the lawn, picking up any stones, nails, etc. which would otherwise damage the knives when the mower is in use. The bearings should be freshly oiled between operations. This makes a great difference to the results and to the operator of the machine by reducing labour. The holes through which oil is to be dripped are easily located. If any have become clogged with dirt, a piece of stiff wire will effect a clearance. Thick oil is a hindrance to free movement, and it is apt to collect dirt and pieces of grass. Ordinary cycle oil is a good substitute if the oil recommended by the makers cannot be obtained.

It is not possible for any machine to cut wet grass satisfactorily; even a motor mower will jib at that.

Moderately dry grass is the best for mowing and, if there is any choice in the matter of time, the cool of the evening will cause less discomfort to the operator of the machine. Short strokes, then a pause, then another stroke, and so on, constitute a common and bad method of mowing. The machine should be run briskly and without pause to the end of the strip.

Bearing down on the handle, or handles, is another common error. The operator should stand up to the machine, so that the front rollers are always in contact with the ground. In some models it is possible to adapt the height of the handles to the user’s requirements, the angle being altered by loosening bolts on cither side of the base of the handles, and retightening the bolts when the angle has been adjusted, see A.

Regulating Cut

The closeness of cut can be regulated; in some types of machine by adjusting the bottom blade to the cutting cylinder (the knives); on other types the bottom blade is fixed and the cutting cylinder has to be adjusted to the blade. The method, in either case, is simple, tightening or slackening of screws being ail that is required. These screws fix the positions of bearings located immediately above and at either end of the cutting cylinder. The makers issue printed instructions covering this and other points regarding operation and maintenance, and a leaflet or pamphlet can always be obtained on application, the number or name of the model being quoted.

Importance of this adjustment must not be disregarded. If the cutting cylinder and the bottom blade make too close contact the machine will be very hard to work. If the bottom blade rubs on the ground the mower will be difficult to push, the grass will be pressed down and imperfectly cut, turf will be sliced off, and the knives may be damaged. Always the bottom blade should clear the ground by not less than {’m.; if the grass is long, the front roller should be lowered so that the blade is raised anything up to about ¾ in., then when the long grass has been shortened the front roller is raised to the normal height to complete the close cutting.

On some types of machine the bracket on either side, carrying the spindles of the front roller is marked with indentations, these enabling the roller to be adjusted at perfect level, whatever the height. Cutting cannot be satisfactory unless the roller really is level. To see whether the bottom blade is clearing the ground, and by how much, the machine should be turned on its side, or turned right over, and a ruler or a straight stick placed across the wood roller and the side wheels (in the case of the side wheel type), or across the wood roller and the large land-roller. This will show the height of the blade: the latter should clear the ruler or stick by not less than }’n.

When a grass box is used, the weight of this (loaded with cuttings) should be borne in mind. If the turf is damp, this added weight will tend to force the bottom blade down; the blade should therefore be somewhat higher than normal. When cutting without a box, the curved metal plate immediately behind the knives should be removed: the cuttings will not then be thrown forward to impede the forward movement of the machine.

To prevent damage to blade and knives when the machine is being moved along a path to or from the lawn, the handle should be depressed, to raise the front roller well clear of the ground; or in the case of the side wheel type the wooden handle should be thrust right over to the other side so that the knives are raised from the ground and taken out of gear.

At least once every season the knives will require sharpening. Like every other edge tool they become blunted with use; and here again the maker’s instruction leaflet should be studied for the correct method of sharpening the knives. It is possible to have the knives sharpened by a firm specializing in the care of lawn mowers, but this is rather expensive, and it is worth doing at home. To sharpen the knives without removing from the machine, the edges of the knives are first liberally coated with oil, dripped on from the oil can; ordinary lubricating oil serves. Then fine emery powder is sprinkled on the oiled edges, also on to the oiled front edge of the bottom blade.

Knives and bottom plate are then adjusted so that these make light (not tight) contact throughout the full length, and the knives are briskly rotated in a backward direction, so that the abrasive puts on a clean cutting edge. In one model of the side-wheel type the procedure is as follows. After the knives and bottom plate have been adjusted so as to touch, the side driving wheels are taken off, and the pinions (together with their pawls) are exchanged: that is the left and right pinions are changed over, the wheels then being replaced. Oil and fine emery powder are then applied, as previously described, the wood handle is pressed down with the left hand until the driving wheels can turn freely, the end of a spanner is inserted in a hole in the right-hand driving wheel, and this wheel is turned rapidly backward, reversing the motion of the knives. The grinding (sharpening) completed, the pinions are replaced in their original positions. With some models of the side-wheel type, a grinding pin is supplied for working the right-hand wheel in the above manner.

Test of sharpening consists in inserting between the blades and the bottom plate a piece of writing paper, or a leaf, then sharply rotating the knives. The paper or leaf should be cut neatly, as though with scissors. The test should be applied at intervals along the bottom blade, and adjustments made until the cut is perfect at all points. If the knives drag against the bottom blade, the grinding should be carried a stage further, more oil, emery powder and rotation applied until the desired result is obtained. The powder should not be allowed to penetrate into the machine; it must be shaken on carefully so that none finds its way to the gears or other moving parts. Clean away all traces of emery powder after the completion of the grinding operations.

There will come a timewhen the bottom blade will be chipped perhaps or blunted, or its extreme ends (not subjected to the general wear) will be higher than the remaining portion. These defects may be remedied by grinding the blade on a grindstone. The blade should be removed (on some types attachment is by countersunk screws on the underside) forrenova-tion by grindstone.

Another counsel of perfection is that the machine should always be thoroughly cleaned, and edges of the knives and bottom blade be greased, after mowing and before it is put away. Mowing being a somewhat laborious task, this desirable attention is more often ignored. In that case, the cleaning must be done before the next mowing starts: knife edges being carefully scraped, the back (delivery) plate cleaned, rollers freed of dried grass, and oil dripped into every point provided. If the machine has been allowed to become very dirty, it can be cleaned by washing it with hot water and soap applied with a hard brush, this to be followed, after drying, by lubrication of the working components.

The efficiency of a motor mower engine depends on the same careful maintenance as the engine of a car, and here the maker’s handbook should be carefully studied.

General Hints

After using the mower wipe the cutting blades and working parts dry. Always store the machine in the toolshed, garage or under a shelter. Damp and moisture can quickly cause deterioration of both the appearance and working efficiency of the machine.

If the machine is to be stored away for the season thoroughly clean all components with a rag and stiff brush. Then dilute some petroleum jelly in a little cycle oil, which can be mixed to a smooth paste in a deep can. Using a small paint brush apply the jelly to all the unpainted metal working parts. Examine the painted parts and if there are any spots which are blistered or show signs of flaking, scrape the paint from the affected area, rub briskly with emery paper until the metal is clean, and apply paint to match the original colour.

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