Machinery checklist: Top tips for spreader accuracy

VANE CONDITION

CONDITION of the vanes has the biggest impact on direction and distance prills are thrown, and these need to be in top condition.

If any pitting can be felt, or the vanes take on a fish scale appearance, these need replacing.

Likewise, the length of the vanes is a vital factor to spreading accuracy, with most vanes showing their length on the side. These should be periodically measured, and replaced if the length becomes lower than the figure given.

When replacing vanes, ensure the correct disc and vane combination are used, and tighten with a torque wrench as per the manufacturer’s guidelines, in this case 20Nm.

It is also advisable to replace the locking nuts and bolts at this time as well.

Any border control vanes should also be inspected for defects, often seen after getting to friendly with hedgerows.

OBSERVATIONAL CHECKS

TO see what needs checking and adjusting, we walked around the company’s Axis 40.2 M-EMC-W.

This mechanically driven spreader is fitted with the firm’s Electronic Mass Control technology, which uses torque sensors to adjust the drop point, said to maintain spreading rate, width and accuracy. Weigh cells were also fitted.

However, many of our checks apply to most makes of spreader.

When going out with the fert spinner, observational checks should be carried out on a daily basis.

Mr Birchall says rust which can be prevented will inevitably rear its head from time to time.

If it is caught early, it can be remedied and patches can be repainted. Checking for play in the discs ensures accurate application and early detection of bearing failure.

While uncommon, it can be a nuisance during busy times, so the advice is if a bearing looks suspect, replace it as soon as possible.

POSITION OF SPREADING DISC HUB

THE next area to measure and check is possibly the most critical and overlooked, says Mr Birchall.

With the spreading disc removed, the spreading disc hub should be positioned exactly under the agitator, with just a 2mm tolerance for misalignment on this model. These should also be checked for cracks.

The distance between the upper edge of the spreading disc hub and the edge of the agitator is often less than it should be, due to the spreader being filled while resting on the floor, says Mr Birchall.

Stresses

Instead of putting the spreader on the floor, he says the spreader should actually be raised 20-25cm off the floor while filling, to prevent putting stresses on the structure between the gearbox and disc assembly and the hopper.

The weight of the fertiliser in the hopper will compress the gap that is needed to maintain an even spread, which on this spreader should be 136.5mm, again with just a 2mm tolerance. If the distance is less than this, it is a task for the dealership to reconfigure.

When reapplying the disc, a line of grease should be put on the threads of the holder to reduce the risk of stripping the threads from the plastic retaining cap, which should be done up hand tight then tweaked further by a quarter turn with a bar.

AGITATOR ATTENTION

AGITATORS in the bottom of the hopper should be given regular attention for signs of wear, and should always cover the furthest point of the aperture from the centre of the agitator.

They should also move freely in one direction, but lock when turned the other way.

Failure to lock is likely to be down to a problem with the con rods which power the agitators off the gearbox.

Grid

On our example machine these were plastic and can be subject to cracking and bending from time to time, so should also be checked regularly.

The grid inside the hopper should also be checked for even squares and replaced if any large holes appear.