THE OPERATION AND MAINTENANCE OF A HEADER HARVESTER

New Zealand Journal of Agriculture, Volume 80, Issue 1, 16 January 1950, Page 43

THE OPERATION AND MAINTENANCE OF A HEADER HARVESTER

ON all farms where grain and seed crops are grown the harvesting of these crops is a very important operation. There is a saying that a crop cannot be judged until it is in the bag, and certainly the return from many crops has been lessened appreciably by mistakes made during harvesting. This article by C. J. Crosbie, Farm Machinery Instructor, Department of Agriculture, Christchurch, describes the mechanism of the latest gift of science and invention to this branch of farming, the header harvester, and recommends methods of adjusting, operating, and caring for the machine to obtain the best results from it.

NOT so many years ago the direct responsibility of the farmer ended before a grain or seed crop was threshed. The stocking or stacking of a grain crop or the cocking after windrowing of peas or grass seed was the duty of the grower, but in most cases the threshing was undertaken by contractors. The large wooden combines and to a less extent the smaller tin mills were machines capable of threshing the produce of a large acreage and were best utilised by contract operators who travelled from one farm to another. Until the mill arrived the unthreshed crop was held either in stocks or cocks or in stacks, depending on the farmer’s judgment of when the mill would arrive. Naturally, the man in charge of the —frequently the owner—had a very good knowledge of the machine he was working and was able to handle it to best advantage under a very wide range of conditions. The introduction of header harvesters brought a marked change in harvesting operations. The header harvester has not the same capacity as either a combine or a tin mill, but can combine the operations for which two machines were previously necessary. Though some header harvesters are operated on a contract basis, they are designed primarily for operation by the farm staff, as are most other farm implements. Though in some ways they may work under a narrower range of conditions than older types of

-threshing machines, they have emphasised the necessity for the closest judgment in determining whether a crop is fit to be harvested. On the other hand, the experience which can be gained by a farmer using his own equipment is restricted in comparison with that to be gained by a contract operator of a threshing mill, and therein may lie the reason for the criticism of header harvesters which is sometimes heard. Purpose of Threshing The essential aim of any threshing operation is to remove the seed or grain from the straw as cleanly as possible, at the same time doing the minimum of damage to the grain or seed and not breaking up the straw and other impurities so that dressing the crop becomes more difficult.; The removal of impurities from the grain or seed is of secondary consideration. From observations by officers of the Department of Agriculture, the most important factor affecting the efficiency of a header harvester appears to be the condition of the crop, the setting of the machine being next in importance. * Further work is being undertaken in an endeavour to define more clearly the nebulous term “in condition for threshing,” though many header harvester operators have been able to determine by experience and to their own satisfaction what this term means. In the meantime this article gives some advice about the setting of the header harvester to enable it to perform its best work. Mechanisms of a Header Harvester Seen for the first time a header harvester appears to be a very complicated piece of machinery, whether it is a modern self-propelled machine with up to 24 forward speeds or the more common trailer-drawn type, driven either by an engine or from the power take-off shaft of the tractor. However, when stripped to its component parts it proves to be a machine which can be understood readily and the work of which can be appreciated even by those who have never operated such a machine. Apart from the engine or engines which provide power to drive its mechanisms and to propel it, a header harvester consists essentially of a wheeled chassis on which are mounted mechanisms for cutting and elevating, threshing, separating, and seed cleaning

Cutting and Elevating Mechanism The crop to be harvested is either direct headed, in which case the seed head is cut from the remainder of the plant by a mower bar mounted on the front of the header, or picked up from a windrow after being cut previously by a mower, binder, or windrower. The cutting mechanism of a header harvester is essentially . the same as that on a mower except that the sections on the knife are usually serrated and the ledger plates plain. For special crops of a fibrous nature that cause blockages at the knife plain sections similar to those on a mower are used. The pick-up for crops that have been wmdrowed may be one of two types—either the rotary-drum type with sets of revolving spring-steel fingers which disappear down between guards at the top of the lift, or the draper type with rows of steel fingers embedded in channel-steel slats on a revolving canvas. In all cases the crop is passed on to an elevating mechanism for delivery to the drum. The elevator may be either a steel slatted conveyer chain or a rubberised-canvas draper. It may be the full width of the cutter bar or the crop may be concentrated into a more bulky swath by augers or a cross-conveyer belt for delivery to a narrow elevating mechanism. The Threshing Mechanism The cut, unthreshed crop is fed into the drum, where the grain or seed is threshed out of the heads by being passed between a rapidly moving cylinder and the shelling . plate and later the concave. The speed of the cylinder is variable through a wide range to meet the needs of different crops and conditions, as is the clearance between the cylinder and the shelling plate and concave.

On entering the drum the . grain first passes over the shelling plate, where it receives its first impact from the bars on the cylinder; here most of the threshing is done. The cylinder bars may be of the peg-tooth type or the rasp-bar type, or they may be faced with rubber vulcanised to the bars. After passing the shelling plate the crop passes over the concave, which may be of the open or closed type, depending on whether any separation of the seed from the straw takes place here. The concave is fitted with devices which obstruct the flow of straw and so ensure complete threshing. Depending on the type of bar fitted to the cylinder, these devices may be peg-toothed bars, rubber-faced bars, or of the rod type, and provision is made for the removal of some of them if conditions make that necessary. Separating Mechanism The seed and straw pass from the drum on to straw walkers or straw shakers, which shake the seed from the straw so that it falls on to the seed tray before being passed to the cavings riddle, while the straw is

passed to the exterior of the machine. The material reaching the cavings riddle consists of seed, long and- short pieces of straw, seed heads (either threshed or unthreshed), pieces of grass or flag, and other small portions of vegetation. The cavings riddle is adjustable so that the straws and larger material pass over and fall to the ground. An adjustable blast of air blows up through the cavings riddle and the tail of the machine. Unthreshed grain and parts of full heads are retained by a device at the end of the cavings riddle and, after being collected in a tray, are cross-augered, carried up in the gleanings elevator, and .returned to the drum for rethreshing. Seed passing through the cavings riddle is delivered on to a set of seed riddles, which may be either replaceable or adjustable for different crops, • and here again material which does not pass through them is caught in the tray and returned to the drum. Seed-cleaning Mechanism From this last riddle the seed is collected in another tray, crossaugered, and raised in the grain elevator to the screen for cleaning. The screen may be replaceable with others having different-sized holes or slots for different crops, or it may be of the adjustable wire-screen type. In either case the aim of this mechanism is to remove some of the weed-seed impurities and to separate the seed into first and second grades if required. Operation of the Machine A recognition of the proper time to start harvesting is essential for the successful operation of a header harvester. All too often a farmer tends to start the machine in a field before the crop is fit for threshing, and this is more common where a crop is to be

direct headed than where it is to be picked up out of the windrow. The ability to decide when a crop is to be harvested can come only after much experience, and in practice the decision is made after such field tests as sweeping ryegrass with a hat or biting grains of wheat. Farmers who do not feel qualified to make such an important decision can obtain advice from neighbouring experienced farmers or from officers of the Department of Agriculture. If there is doubt whether the crop is fit for harvesting, samples of wheat may be sent to the Wheat Research Institute or its substations for moisture determinations; results of tests are quickly communicated to the farmers concerned. In general it is not advisable to direct head wheat with a moisture content of more than 16 per cent. If the crop is fit and the weather right, the header harvester may be brought into operation, and whether the machine does poor, fair, or good work will depend entirely on how well the operator knows his machine and the principles of the adjustments that have been built into it and whether he applies his knowledge. The header harvester has been evolved to combine in one machine four operations of harvesting that were previously done separately, and its components are variable so that each may be fitted to handle the flow of material from the previous one. Further, though a machine may be made to perform efficiently under one set of conditions, where the conditions vary from crop to crop, from day to day in one crop, and even during one day in the same crop, as they do when harvesting with a header harvester, the parts of the machine must be variable to allow for those varying conditions. To understand the adjustment of these, parts and to apply such knowledge to the conditions of the crop being harvested is the secret of successful and efficient heading. The adjustments of the header harvester include the following:— Flow Control The flow of material entering the drum is one of the factors affecting threshing and may be controlled in one of several ways: —

If the crop is windrowed and picked up, the windrow should be even along its length and of such a size that it can be handled by the machine. Too big a windrow makes for inefficient threshing, and seed still in the ear is dumped on the ground. Again, if the windrow is too bulky, seed may not be shaken out of the straw as it passes over the straw shakers and so is lost on the ground. Too small a windrow, on the other hand, causes hard threshing and damage to the seed.

Speed of travel is important, as the rate at which the windrow is fed into the drum has just as great an effect as the size of the windrow, because the same factors operate. Driving too fast leads to overloading the drum, resulting in threshing losses and carryover of seed from the straw walkers. That speed is important has been realised in the past, for some farmers have had special double gearboxes fitted to their tractors so that lower and , intermediate gears not provided by the tractor manufacturers could be

used. Of recent years new self-pro-pelled header harvesters have been fitted with variable sheaves in the drive power line so that up to 24 forward speeds are available. If the crop is being direct headed, the problem is easier because less straw is taken from the plant and therefore more heads may be put into the flow of material to the drum. However, practice is needed before the operator can distinguish the even rhythm characteristic of a well-fed drum operating at maximum efficiency without either overloading or running partially full. Operation of the Drum The sole function of the drum is the threshing of the seed from the ‘ seed head, and this is controlled by two adjustments, both of which are of primary importance. The mishandling of either or both can spell failure of the whole operation.

Speed of the drum: When a field is being opened up the drum should be set at the manufacturers’ rating for the crop, but that rating is at best only a guide and variations probably will be necessary to suit individual conditions. Drum speed controls threshing and needs to be varied with the volume and condition of the crop. In general, higher speeds are necessary for heavy or slightly c damp crops and lower |

speeds for light or dry crops,. but too high speeds lead to seed damage and excessive chaffing of the straw. Setting of the concave: The peg type of drum is adjusted by altering the number of pegs on the drum and the number of rows of pegs in the concave, those taken out being replaced with blanks, and by using different sizes and shapes of pegs for different crops. The centring of the pegs of the drum between those of the concave is important. The adjustment in the beater type of drum is the distance between the drum and the concave; in some machines the concave and in others the cylinder is adjustable up or down. The adjustment of the shelling plate is also important and, if required, concave bars may be taken out. As for the drum speed, the manufacturers’ recommendations for concave settings should be used as a guide when starting a field, but they may require alteration to suit the conditions. With the drum and the concave set as suggested, the straw should -first be examined for seed left in the heads. If they are present, an increase in drum revolutions is indicated, and if the - machine has a shelling plate, an adjustment there might be necessary. In general, increasing the drum revolutions is a safer method of improving threshing than closing the concave settings, for knocking the seeds out of the head by impact from the cylinder bars is safer than rubbing them out between the cylinder and the concave. Then the sample of threshed seed should be examined for cracked, broken, or excessively skinned seed. If damage is present, the concave requires to be opened or the drum speed reduced. If there is excessive chaff and straw on the cavings riddle, the fault is in too close concave settings or too high drum speeds. If the humidity alters during the day, alterations to the drum settings will be necessary, and it should be a

general rule to check the machine during the day to determine whether alterations should be made. Cavings Riddle The cavings riddle is adjustable to allow the seed to fall through it and the straws and unthreshed heads to pass over it while a blast of air comes up through it to remove chaff and light matter. If threshed, seed is passing over it and being returned to the drum, the riddle needs to be opened, but not so far as to allow - straws to pass through it, or the blast may be too vigorous and may be blowing the seed over the riddle. In general, the aim is to have the flow of material floating over the cavings riddle so that the seed is on the bottom and the light material held above it by the blast. The tailings attachment is an extra fitting which may be added to the cavings riddle to increase its area and bring about better separation under more difficult threshing conditions. The attachment is adjustable. Unthreshed heads pass over the cavings riddle and its attachment and return to the drum for rethreshing.

The Blast The blast of air used to separate the chaff, husks, and light material from the seed is produced by a fan operating at constant speed but with either adjustable inlet or discharge gates or both. The strength of the blast is adjusted to suit conditions in the field so that a clean sample of seed is obtained. However, when high-grade small seeds are being harvested it is probably better to reduce the blast so that all the seed and some inert matter is bagged than to blow off the inert matter and some of the seed with it. Seed-cleaning firms have specialised plants and can clean up a line of seed more economically than can a farmer with a header harvester. The return from seeds that he will blow over the riddles of his machine usually will more than pay a firm to clean out the inert matter he is trying to get rid of. When a crop is being headed in a strong wind the blast requires frequent attention as the machine moves round the field to compensate for the direc-

tion in which the wind is blowing into the harvester. The Riddles An adjustable riddle or a replaceable one with holes or slots suited to the crop is fitted under the cavings riddle, ana seed passing through this riddle is led to the screen. The purpose of this riddle is further cleaning of the sample, and if the operator of the machine is so proficient that he is obtaining a clean sample off the cavings riddle, as is possible sometimes with grain and linseed, this last riddle may be left out; however, if there is any trace of inert matter, it is better left in to obtain a clean sample. If too great a quantity of crop is being handled by the machine, the riddle may become overloaded and some threshed seed may pass over it to return to the drum, where it is rethreshed, so increasing the possibility of damaged seed. The remedy in this case is obvious.

For efficient riddling the material must pass over the full width of the riddles in an even stream, and to aid this the riddles must be level. On flat fields the height of the drawbar of a trailer-drawn header harvester must be set so that the riddles are level. If the nose is low, the seed moves to the front of the machine so that it comes on to the riddles in a thick stream, uses only a portion of the riddle area available, and as a result overloads it. For operation on hillsides selflevelling devices are fitted to header harvesters so that their riddle boxes are automatically levelled up, and in some cases an additional automatic air blast ensures a more even depth of material as it passes over the riddle. One new machine imported recently has a -levelling device to keep the riddles level lengthwise, and a manually-controlled power drive raises or lowers the wheels so that the machine is kept vertical and the riddle box horizontal across its length when it is operating on hillsides. The Screen A header may be fitted with a replaceable set screen or wire screen adjustable for all crops. Here any remaining impurities such as broken seed, some weed seeds, and small particles of soil and dust are removed from the sample of seed, which may be divided into first and second grades. Care of the Machine Though a header harvester appears complicated,, it is not if the operator understands his machine. He soon becomes adjusted to the regular rhythm of an efficiently operating header harvester, and any departure from this rhythm will jar on his senses so that he will stop the machine immediately and effect the necessary adjustments or repairs. Lubrication Before a header harvester is started, even for a trial run in the yard, it must be lubricated adequately by

following the makers’ recommendations. With its multitude of drives, cross-shafts, and pulleyssome turning at up to 1600 r.p.m.regular greasing of all bearings is essential, even though the fast-moving ones are running in high-grade roller and ball bearings. Oil levels in the gearboxes must be maintained and . the oil changed regularly. During working days the machine must be greased as suggested by the manufacturers, and more often if conditions are extremely dusty, as when working in peas. Care. should be taken not to grease parts too much at one time, for excess lubricant rapidly works out of a bearing. The excess from an internal bearing contaminates the seed sample, and some of the grease from an exterior bearing will fly on to the rubber belts and perish them. Grease should never be allowed to remain on rubber belts or tyres, as it perishes the rubber, and this action is speeded up in hot sunshine. An efficient grease gun of large capacity, preferably of the lever-action type with a clip-on nozzle, is a valuable asset to the farmer with a header harvester and speeds up greasing markedly. . Adjustments and Replacements Apart from the check it receives each time it is lubricated, at intervals

during the season the header harvester should be checked thoroughly for loose bolts and rivets and all deficiencies repaired. If a breakage occurs, it is important to determine its cause before the part is replaced. If the breakage was the result of normal wear or a defect, the part may be replaced at once, but if misalignment of surrounding parts caused the breakage, it must be corrected before the part is replaced or the new part will soon break. Carrying and Ordering Spare Parts It is difficult to advise what spare parts should be carried by a farmer as insurance against long breakdowns, which may cause the loss of a crop because of wind or rain or both. At all times there should be carried on the header harvester a bag of bolts, nuts, and washers of assorted sizes, cotter pins, grub screws, grease nipples, rivets, and spare knife sections and ledger plates. In' addition, it is wise to carry spare links suitable for the chains used in the drives and, especially if the machine has been in use for a season or two, spare V belts if they are of a size not readily obtainable on the local market. Where the machine is working on stony ground a spare set of drum bars is good insurance against delay should a big stone be picked up and passed through the drum.

When spates are being ordered from the local agent the serial number of the machine should be quoted first, followed by the number and full name of the part required. A few minutes spent in checking the number and correct name of the part in the repair parts book supplied with the machine may obviate hours of delay in replacing the part. Machinery firms realise fully the urgency of a call for spares during the harvest season and exploit all methods of transport to get the part to the farm in the shortest possible time. Co-operation by farmers assists them in their work and reduces delay to the minimum. Storage At the close of a season the header harvester should be put in a shed and cleaned thoroughly. All excess grease should be removed and dust and vegetation cleaned out, as they collect moisture during damp weather and set up rusting. After it has been cleaned the machine should be greased and all V belts taken off and stored in a cool place. The tension should be taken off all canvases and drapers. The machine should be overhauled thoroughly and all nuts and bolts checked for tightness. The use of spring washers is advocated. Repair work should be attended to during slack periods. If more attachments are required . for the following season’s work, they should be ordered and fitted before the rush of work at the beginning of the season. The weight should be taken off spring parts and the machine jacked up and put on blocks to take the weight off the tyres. • If the header harvester is engine functioned, the petrol tank should be emptied, the crankcase drained and refilled after being washed out, and the radiator drained. A good practice is to remove the spark plugs, squirt light oil into the cylinder head so that it forms a layer on top of the pistons, then turn the engine over by hand several times to ensure that the cylinder walls- are well lubricated. Sometimes stored engines are started and run for a short time once or several times during the storage period, but unfortunately the good accruing from the lubrication obtained in this way is offset by the harm caused by acids formed as a result of by-products of combustion in the form of exhaust gases combining with water vapour. Acids, formed in this way corrode the cylinder walls and other parts, and therefore it is not recommended that engines be started during the storage period. Electrical fittings should be checked and any frayed or worn leads repaired or replaced. Parts subject to deterioration by moisture should be protected during winter. Parts with chipped paint should be repainted to protect them from corrosion and rusting. In general, if a header harvester is cared for adequately during the off season and understood and used intelligently during its working season, it will perform satisfactory work, but like any other machine it is only as good as its operator makes it.

Safety Precautions with a Header Harvester

\A/HEN operating under field con- ’ * ditions a header harvester requires to be lubricated at least three times a sometimes moreand while carrying out this work the operator must, climb all over the machine to reach grease nipples. Because the soles of his boots are slippery as a result of working in the harvest field, he runs a grave risk of slipping and injuring himself as he climbs up and over the steel of the machine. This illustration shows two additions fitted to a standard machine as supplied by the manufacturer which greatly improve the safety of its operation. ..

A steel ladder, cheaply welded up from scrap angle iron and fitted at little effort . and cost ,to the rear of the machine, enables the operator to climb quickly to the top of the machine to carry out adjustments, examinations, or lubricationall with greater ease and at minimum risk of slipping. Two white flags IBin. x 9in. clearly indicate the -width of the machine when it is on the road.’ One of these flags, rolled up and folded back during field work, is indicated by an arrow in the illustration. The provision of . these two flags complies with the Transport Department's regulation governing the haulage of over-width vehicles on the road during. daylight, and some farmers and most contractors . move their machines along roads during the'season's work.

Important, precautions with a header harvester are:— . If the machine is operated by power take-off, keep all shields in place. Do not adjust, alter, or grease a machine in motion. Do not operate a header harvester on a hillside the steepness .of which endangers the stability of the machine. —C. J. CROSBIE, Farm Machinery Instructor, Department of Agriculture, Christchurch.