Har­vester Buy­ers’ Guide

Ex­pert tips for buy­ing a new com­bine har­vester

Farms & Farm Machinery - - Contents -


The com­bine har­vester is prob­a­bly one of the most im­por­tant in­ven­tions in the agri­cul­tural in­dus­try as it helps farm­ers save se­ri­ous time and labour costs at har­vest.

How­ever, due to their sheer size and com­plex tech­nol­ogy, com­bines do not come cheap. The price, de­pend­ing on the com­bine class, can eas­ily ex­ceed half a mil­lion dol­lars. Hence it is cer­tainly not an in­vest­ment farm­ers take lightly.

There­fore, if you are in the mar­ket to pur­chase one for your op­er­a­tions, it is cru­cial to know what to look for and points to con­sider be­fore com­mit­ting to a po­ten­tially life-chang­ing de­ci­sion.

First of all, what are you ex­pect­ing out of your har­vester? A good har­vest­ing op­er­a­tion should en­sure:

• A timely har­vest

• Max­i­mum grain in the bin

• An op­ti­mal through­put

• Har­vested prod­ucts are of the best qual­ity

• Har­vest is un­der­taken with least amount of losses

• An economical and re­li­able op­er­a­tion.

Mod­ern grain har­vest­ing ma­chines op­er­at­ing in Australia are all ro­tary or hy­brid-ro­tary ma­chines. Com­bines with walker-type sep­a­ra­tors have all but been su­per­seded and hence will not be con­sid­ered in this piece.


In the ‘good old days’ of walker-type ma­chines with tan­gen­tialfeed cylin­ders, com­bine ca­pac­ity was prac­ti­cally de­pen­dent on and mea­sured or rated by cylin­der and walker width. That all changed when ax­ial flow ‘ro­tary’ de­signs came on the scene after 1977 and th­ese have eclipsed cylin­der ma­chines. Nowa­days com­bine ca­pac­ity is largely dic­tated by en­gine power and clean­ing shoe area.

So what are com­bine classes and what dic­tates which classes a com­bine should fall un­der? As a rule of thumb, the higher the power, the higher the class. For ex­am­ple, Case IH’s Ax­ial Flow 6130, which of­fers 320hp, falls un­der Class Six, while Claas’ Lex­ion 750 with 442hp sits un­der Class Nine.

How­ever, the guide­lines in com­bine clas­si­fi­ca­tion of­ten change. More of­ten than not, man­u­fac­tur­ers cre­ate their own classes when they pro­duce a ma­chine out­side a spec­i­fied class. Hence, com­bine class rat­ings may be de­cided more by mar­ket­ing in­tel­li­gence than by engi­neer­ing fea­tures.

Com­bines of­fered to­day in Australia ranges from Class Six to Class 10.


Given the time pres­sures at har­vest, it is crit­i­cal that the ma­chine be re­li­able. This means choos­ing a brand with rep­utable prod­uct back-up and dealer per­for­mance.

Think well-known, tried and tested brands such as John

Deere, New Hol­land and Case IH, which have a wide net­work of deal­ers, mean­ing backup and parts won’t be a prob­lem. Make sure your deal­er­ship is not too far away should you run into any prob­lems and that they have a good parts backup.

Some brands might even have mo­bile ser­vice trucks in se­lected re­gions come har­vest time for 24-hour ser­vices should prob­lems oc­cur. Just be sure to ask the ques­tion when it’s time to buy.


A sim­ple but very im­por­tant rule to re­mem­ber is: a com­bine’s ca­pac­ity should never be more than the gath­er­ing head can di­gest.

As har­vest­ing starts from the front, gath­er­ing sys­tems are crit­i­cally im­por­tant in the over­all scheme of grain har­vest­ing and should be taken into con­sid­er­a­tion when pur­chas­ing your har­vester.

Some might think the head is not a pro­ces­sor but con­sider this ex­am­ple: In some con­di­tions a strip­per head can thresh out more than half the grain right at the front. Since the strip­per head cap­tures only the ears, crop char­ac­ter­is­tics are crit­i­cal for its per­for­mance.

While strip­per heads can be use­ful in no-till con­ser­va­tion farm­ing be­cause straw is left in­tact, an­chored and stand­ing, there can be a se­ri­ous gath­er­ing loss penalty with a strip­per head in ce­re­als.

Types of grain head­ers:

• Auger-type or ‘tin’ fronts. Th­ese head­ers are equipped with a re­cip­ro­cat­ing knife cut­ter bar with a me­tal or plas­tic re­volv­ing reel which makes the crop fall into the head. A cross auger then pulls the crop into the throat of the har­vester • Draper-type heads. A fab­ric or rub­ber apron takes the place of the cross auger on auger-type head­ers which al­lows faster feed­ing into the pro­ces­sor for bet­ter thresh­ing per­for­mance • Windrow pick-up heads. Th­ese fea­ture spring-tined pick-ups, usu­ally at­tached to a heavy rub­ber belt. They are used for crops that have al­ready been cut and placed in windrows or swaths • Strip­per heads. This header fea­tures a ro­tat­ing ro­tor fit­ted in the front of the header which strips grain from the crop as the com­bine moves the head for­wards

• Crop-spe­cific heads. For best har­vest per­for­mance, many crop species re­quire their own pur­pose-built heads. Ex­am­ples in­clude corn, sun­flower, cot­ton (picker heads), rice, soy­bean and sorghum.


The com­bine you choose re­lies heav­ily on the crops you’re har­vest­ing and the com­bine’s main ac­tiv­ity hub – the pro­ces­sor – and whether the con­fig­u­ra­tion suits your needs.

Here is a gen­eral over­view of dif­fer­ent com­bine pro­ces­sor con­fig­u­ra­tions on the mar­ket to give you a ba­sic idea:

• The New Hol­land com­bine se­ries has a wider front el­e­va­tor for bet­ter feed­ing into the twin ro­tors com­pared with sin­gle-ro­tor ma­chines

• AGCO’s Gleaner com­bines have tan­gen­tial feed into their

trans­verse-mounted pro­cess­ing ro­tor

• Claas re­tains tan­gen­tial feed into its APS pro­ces­sor with three tan­gen­tial cylin­ders up front, feed­ing into ei­ther walk­ers or two ax­i­ally-ori­ented sep­a­rat­ing ro­tors. This sys­tem is well suited for long-strawed crops and higher-mois­ture con­di­tions • John Deere and Case IH’s ax­i­ally-aligned pro­cess­ing ro­tors use guide vanes on the top of the ro­tor cas­ing to di­rect the crop back­wards.

The con­cave grates, on which the thresh­ing drum beats to cre­ate the thresh­ing ac­tion re­quired may need to be changed for dif­fer­ent crops but all have clear­ance ad­justa­bil­ity.

Many lat­est com­bine har­vester mod­els have au­to­matic in-cab ad­just­ment of var­i­ous set­tings such as con­cave clear­ance and shoe open­ings to match the pre-se­lected crop.

Al­ways check the set­tings as an over-ag­gres­sive pro­ces­sor and in­cor­rect con­cave clear­ances can lead to grain dam­age; the faster the ro­tor speed and the tighter the con­cave clear­ances, the greater the dam­age.

Bro­ken grain doesn’t make it up into the grain tank so yield is re­duced. Some mod­els even have grain-dam­age sen­sors which are usu­ally based on video cam­era frame-grab as­sess­ment.

In any event, oc­ca­sion­ally check­ing tail­ings re­turn flow is es­sen­tial to see if the re­turns are grain-rich or residue-rich and whether there is ex­ces­sive cracked grain in the sub­sam­ple. The greater the straw break-up by the pro­ces­sor, the heav­ier the load in the clean­ing shoe which leads to shoe losses over the back.

Mod­ern ma­chines have grain-loss mon­i­tors, but be aware th­ese only mea­sure rel­a­tive loss. It is rec­om­mended you pe­ri­od­i­cally get out of the ma­chine to check the ground for ac­tual losses.


Mod­ern com­bine har­vester de­signs have ‘hun­gry boards’ to hold a max­i­mum amount of grain, up to 14,100 litres (400 bushels), in the tank be­fore un­load­ing. Ideally, the boards should be ca­pa­ble of be­ing closed to pro­tect the load in a rain event.

Check if the un­load­ing auger has plenty of reach to get out past the widest grain head you plan to use. Un­load­ing rate is also an­other im­por­tant con­sid­er­a­tion. Ev­ery minute counts, so more than four min­utes of un­load­ing time is wasted time.


What do you plan to do with the waste from your har­vest­ing op­er­a­tion? The an­swer will dic­tate what you should check for at the back of the har­vester.

Usu­ally, it is de­sir­able to spread the dis­charge evenly to the same full width of the gath­er­ing head to fa­cil­i­tate sub­se­quent pad­dock op­er­a­tions. If on the other hand you bale straw or burn, you may want the ef­flu­ent dropped in a rea­son­ably tight windrow.

Most mod­ern ma­chines nowa­days of­fer a wide range of residue man­age­ment op­tions. Whether you want the waste to be spread wide or into windrows, a push of a but­ton does it for you.


A 400-bushel bin full of wheat weighs some 12 tonnes – add that to the weight of the com­bine and you’re talk­ing about up to 30 tonnes all-up weight.

This can cause sig­nif­i­cant field com­paction so choose your tyres based on load-car­ry­ing ca­pa­bil­ity, mo­bil­ity, ride, trac­tion and stub­ble-wear re­sis­tance. An­other way to go is half or full tracks.


For any­one who’s been in a mod­ern com­bine har­vester’s op­er­a­tor sta­tion, you can agree it looks more like an air­craft cock­pit than a har­vester cab. Con­trols are usu­ally well cov­ered if you’ve cho­sen a rep­utable brand as you’ll be able to control al­most ev­ery­thing, from the op­er­a­tion of the ma­chine it­self to the con­fig­u­ra­tion of ma­chine com­po­nents to suit dif­fer­ent crops.

There are even so­phis­ti­cated auto-steer­ing and mon­i­tor­ing sys­tems built in to en­sure farm­ers get max­i­mum har­vest­ing ef­fi­ciency with­out do­ing much at all.

One im­por­tant fac­tor to con­sider is whether you’ll feel com­fort­able sit­ting in this con­fined space for hours on end. Check for crea­ture com­fort fea­tures such as stor­age, en­ter­tain­ment sta­tions, and com­fort­able seats that pro­vide max­i­mum sup­port.


In se­vere hot and windy con­di­tions, it is cru­cial to be able to rapidly ac­cess work­ing ar­eas of the ma­chine es­pe­cially the en­gine bay.

On high fire-risk days it can be nec­es­sary to check and blow down the en­gine bay on ev­ery round to avoid fire haz­ards caused by ac­cu­mu­lated residues on hot spots like the ex­haust man­i­fold.

The worst crops for fire haz­ard are lentils, sun­flow­ers, chick­peas and so on, but most crop dusts and residues can be­come flammable.


The seven P’s ap­ply here: price, per­for­mance, power, parts and prod­uct sup­port, pres­tige and pur­chase (or not).

If you can af­ford them, there are sev­eral in-cab op­tions you can buy with your har­vester such as grain-dam­age mon­i­tors that mea­sure rel­a­tive grain qual­ity on-the-go. How­ever, this type of in­stru­men­ta­tion and loss mon­i­tors are no sub­sti­tute for phys­i­cally check­ing and mea­sur­ing losses from time to time. Re­mem­ber also that a speedy har­vest may not be the best har­vest. At higher speeds, gath­er­ing and pro­ces­sor losses may in­crease.

How­ever, there is a ‘sweet spot’ – es­sen­tially, a through­put where peak har­vested yield in the bin is op­ti­mal.

Then there is the mat­ter of money. Cap­i­tal in­vest­ment in a new Class Nine com­bine har­vester with head and trans­port cart can eas­ily ex­ceed half-a-mil­lion dol­lars. Are you pre­pared to part with that amount of money? More im­por­tantly, do you need to?

With the in­vest­ment of half-a-mil­lion dol­lars tied up and de­pend­ing on an­nual hours, you could be look­ing at an own­ing and op­er­at­ing (O&O) cost of more than $400 an hour. Un­der those cir­cum­stances it is es­sen­tial to log more than, say, 500 sep­a­ra­tor hours a year just to jus­tify own­ing a com­bine.

Oth­er­wise it would be more cost ef­fec­tive to hire in a cus­tom con­trac­tor rather than buy­ing your own ma­chine. If you elect to hire a con­trac­tor – are they go­ing to be avail­able at peak har­vest time? Can you check their per­for­mance?

There is much to think about.

Op­po­site: Claas Lex­ion 750 work­ing canolaIl­lus­tra­tion, top: Cross sec­tional schematic of a Shel­bourne Reynolds type of strip­per head. This de­sign en­ables faster har­vest­ingAbove: John Deere mar­kets its S-se­ries com­bines in Australia; the S660 is a Class Six com­bine, while the S690 a Class Nine

Above: In­side the ‘cock­pit’ of New Hol­land’s CR10.90 com­bine har­vester

Above: The Case IH 7140 com­bine har­vester

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