Three-Furrow versus Four-Furrow Reversible Ploughs: Part Selection Differences

Three-furrow and four-furrow reversible ploughs look similar and use the same plough bodies, but their frames, beams and linkage parts are different. Ordering parts for the wrong size leads to brackets that do not fit and frames that will not line up. Knowing the differences makes spare parts selection faster and avoids the wrong bracket on the shelf.

Bodies are shared, frames are not

The plough bodies themselves, shares, mouldboards and coulters are usually interchangeable between the two sizes, because each body works as a unit. The frame beam, however, is longer on the four-furrow model, with one extra body bracket spaced along it. A four-furrow beam will not fit a three-furrow hitch, and a three-furrow beam lacks the extra bracket.

Hitch and linkage components

The four-furrow plough is heavier and carries more load, so its lower link pins, top link brackets and hydraulic ram are often upsized. The reversal ram on a larger plough has more work to do, and its rating is higher. When ordering linkage parts, identify the plough size from the frame label rather than assuming a shared part.

Draft and power considerations

A four-furrow plough needs more tractor power and a stronger hitch than a three-furrow model. Parts sized for a three-furrow plough fitted to a four-furrow frame will fatigue faster. Match the pin, bracket and ram ratings to the actual plough size, and check the rating plate before ordering.

Spare parts planning

For a mixed fleet, keep body spares (shares, mouldboards, coulters) as shared stock, but keep frame and linkage parts specific to each size. Label the part numbers clearly so that a four-furrow bracket is not fitted to a three-furrow frame by mistake. A clear parts list saves time in spring and avoids mid-season errors.

Check before you order

When in doubt, quote the plough model, furrow count and frame serial number to the supplier. A picture of the damaged part, measured against the original, removes ambiguity. With the right parts matched to the right size, both ploughs keep working through the season without fitting problems.

References

BROWN R T, DAVIES M K. Part commonality across reversible plough frame sizes[J]. Biosystems Engineering, 2019, 184: 170-178.

Brown, R. T., and M. K. Davies. "Part Commonality across Reversible Plough Frame Sizes." Biosystems Engineering, vol. 184, 2019, pp. 170-178.

Brown, R. T., & Davies, M. K. (2019). Part commonality across reversible plough frame sizes. Biosystems Engineering, 184, 170-178.