Setting the Clearance between Share and Mouldboard on a Reversible Plough

When a plough body is assembled or a share is replaced, the clearance between the share point and the mouldboard sets how the furrow slice flows. Set it too tight and soil jams at the joint; set it too loose and the slice catches on the gap. A correctly set body turns cleanly and pulls easier. The adjustment takes minutes and makes a visible difference to the finish.

Why the gap matters

The share begins the cut and starts the slice turning. The mouldboard then carries and inverts the slice. Where the two meet, the slice must transfer smoothly from share to mouldboard without catching. A step or gap at the joint lets soil hang up, which drags on the pull and leaves an uneven furrow surface.

Fit the share squarely to the body

Start by fitting the share to the body bracket without forcing it. The share should sit flat against its seat, with no gap along the joint line. A bent share or a dirty seat leaves a step at the joint. Clean the seat, check the share for twist, and tighten the fixing bolts evenly so the share pulls down flat.

Check the joint line

With the share fitted, run a straight edge along the joint between share and mouldboard. The two should meet in a smooth line, with the mouldboard face level with the share surface. A visible step upward means the share sits too low; a recessed step means it sits too high. Small shims under the share seat correct the alignment, or the body bracket may need cleaning.

Test the flow in the field

After assembly, take a trial furrow and watch the slice as it turns. Clean flow, with no soil hanging at the joint, means the clearance is right. If the furrow drags or piles up at the body, re-open the joint and re-check the alignment. Different soils show the difference quickly: sticky clay exposes a bad joint faster than light loam.

Re-check after share changes

Every time a share is replaced, check the joint alignment again. New shares from different makers may sit slightly differently, and a body that worked perfectly with the old share may need a small adjustment. Keep a small shim kit in the tool box, and the body stays clean-working for the life of every share set.

References

BROWN R T, DAVIES M K. Share to mouldboard clearance and plough body performance[J]. Biosystems Engineering, 2019, 184: 190-198.

Brown, R. T., and M. K. Davies. "Share to Mouldboard Clearance and Plough Body Performance." Biosystems Engineering, vol. 184, 2019, pp. 190-198.

Brown, R. T., & Davies, M. K. (2019). Share to mouldboard clearance and plough body performance. Biosystems Engineering, 184, 190-198.