SP FAQ - Engineering design
Cross Slot openers and machines have a 10,000- 20,000 hour design life, which is similar to tractors. The designers of Cross Slot reasoned that if a farmer ends up owning only a tractor, sprayer and Cross Slot seeder (as many already do) it makes sense for the seeder to last as long as the tractor and the sprayer, both of which are likely to be designed with 10,000-20,000 hour lives. This is more particularly so with expensive no-tillage machines. The economics of owning a sophisticated no-tillage seeder make much more sense if the replacement period is 10+ years rather than 3 years.
Unfortunately yes! But at successive No-Tillage Conferences it is clear that this is simply not the case in practice with most no-tillage machines. No-tillage machines have much larger stresses applied to them than conventional seeders because the soil has not been pre-loosened. Even some machines from reputable manufacturers are lasting less than three years because they have been designed more as enlarged versions of conventional machines than as specialist no-tillage machines. The shortest time we have known a rival no-tillage drill to wear out in was three months.
Just about everything, but especially pivoting joints and bearings. Of course the soil-engaging components (shanks, discs, blades and scrapers) are expected to wear out anyway, but when the above-ground components of other openers become loose, openers become misaligned, row spacing suffers, residue handling suffers, seed placement suffers, different openers on the same machine behave differently, and downforce application becomes inconsistent.
Some people certainly argue that way. But since a disc is a moving part and handling heavy residues in narrow rows is not possible without a disc of some description, and no-tillage is all about retaining crop residues, there is a limit to the trade-off between simplicity and achieving biological reliability, erosion control, sustainability, and profitability.
Cross Slot places biological performance as the single most important issue and has designed innovative mechanical systems to ensure this remains so over an unusually long service life. This undoubtedly adds to the cost of Cross Slot machines, but we have yet to meet anyone who wants us to reduce either the longevity or biological reliability of Cross Slot machines.
All major pivoting joints use pre-packed ball or roller bearings similar to how tractors (and cars) are constructed. Special triple-lipped seals running on stainless steel backing plates are employed that ensure bearings continue to stay clean even in the dustiest conditions. There are only three grease points per opener that require regular (and then only monthly) attention. All other pivots (including disc and press wheel axles) only require checking once per season.
Blades are tipped with tungsten carbide ensuring that their useful lives are comparable with other openers.
True. Operators in New Zealand probably demand more from their equipment than operators in most other countries. Cross Slot seeders in New Zealand operate for up to 9 months of the year and invariably sow two or more crops per year. Much of this drilling in New Zealand is done on steep hillsides and fences surround all fields with relatively narrow (3.5 - 4.5 m wide) gateways. Most New Zealand no-tillage seeders and planters are therefore relatively narrow machines and drill more repeat rounds when sowing a given field than where wider machines can be utilized. They therefore travel substantial distances each year in drilling mode.
In Australia and North America it is common to get 5,000+ acres from a set of Cross Slot blades and about half this area from a set of Cross Slot discs.
Currently Cross Slot openers use a nickel-chromium alloy that is used by many manufacturers to cast the non-rotating soil engaging components. But we are also working with engineering research groups to develop new ceramic materials that promise to extend the useful life of blades still further.
Surveys conducted on the New Zealand machines over 5 years show that the average cost for soil-engaging component wear is about NZ$7-10 per hectare (equivalent to US$2 - 3 per acre). In high clay content soils this cost may be halved and in abrasive soils it may be doubled.
150 mm (6 inches) is common. Of course there is no upper limit to row spacing.
There are several other no-tillage openers capable of operating at 150 mm (and even closer) spacing but none that apply fertilizer simultaneously with the seed. Most others that apply fertilizer have a minimum row spacing of 180 mm (7 inches) or wider because of the complexity of their designs, which consist mainly of two openers, joined together.