Even the fanciest field drainage system relies on a periodic pass with a mole plough to keep it performing at its best.

Never is this more apparent than a wet season on clay ground, where the strips of land between drains often cry out for some waterlogging relief.

Using a mole to cut a series of underground channels perpendicular to the main network will whisk water away, keeping soils in a workable condition for longer and preventing roots sitting in stagnant mud.

See also:  How, why and when to mole drain

They might seem simple, but there’s more to these machines than meets the eye.

In addition to keeping the bullet and expander (a metal or ceramic former) running perfectly level and at a consistent depth, they need to clear trash and enter/exit the ground cleanly to avoid making a mess.

Maidwell

For more than 40 years, Northamptonshire farmer and contractor Ron Hankins has been building heavy-duty mole ploughs.

His Maidwell Molers come in single- or twin-leg mounted formats, or on a trailed chassis with up to three legs.

All versions use a wide beam setup that leaves plenty of space for trash to flow through.

Common features across the range include shear-bolt leg protection, a cutting disc and a screw adjuster for altering the pitch of the bullet.

All have the option of press wheels, which reduce the amount of surface disturbance and make them suited to working in grassland or no-till systems.

Mounted machines are easier to pull, thanks to a low three-point linkage that helps transfer weight onto the back of the tractor.

And if this doesn’t provide sufficient grip, additional weights can be added to a frame on the moler’s headstock.

This setup means single-leg mounted models can be pulled with 150-200hp, while twin-leg versions require 300hp or more.

For neat entry and exiting of the bullet and expander, Ron has incorporated a swing-arm top link that raises/lowers the front of the rig first to minimise soil heave.

Trailed versions achieve a similar action thanks to the geometry of the frame and the hydraulic ram that puts the machine in and out of work.

Prices start at £6,950 for a single-leg mounted, with twin-leg models starting at £13,500 and three-leggers at £35,000. Press wheels are an extra £750 each.

TWB Machinery

The Magic Mole from Sleaford-based TWB Machinery comes in three guises to suit different sized tractors.

All use the same enclosed beam format, which is designed to give a consistent working depth and reduce surface soil disturbance.

An adjustable front blade can be used to push debris out of the way, removing the risk of it wedging under the beam and altering the path of the bullet and expander.

Depth is altered simply by moving the position of a pin in a series of holes in the leg, shear-tabs protect against collisions with immovable objects and there are shims for altering the bullet angle.

Floating linkages are also fitted on mounted and trailed twin-leg models to help the beams glide over ground contours and pull the leg in and out of work cleanly.

As for power, single-leg machines require at least 160hp up front, and twin-legs need more than 300hp.

Prices start at £6,500 for a single-leg mounted, with single- and twin-leg trailed models costing £7,750 and £16,000 respectively.

Claydon

Claydon is a recent entrant into the mole drainer game, having introduced a mounted model with pivoting headstock.

The pivoting headstock allows drivers to turn the tractor at field ends while the mole is still in work, allowing the channel to extend further over headland drains.

Adjustable lifting chains are integral to the design, providing enough slack for the plough to be raised during turning.

In addition, the length of these can be fine-tuned so that the front skid lifts before the leg, causing it to glide cleanly out of the ground rather than pulling up a lump of soil.

A long 3m beam is said to give precise control of the bullet and sits at only 200mm wide to minimise damage when mole draining in standing crops.

At the rear, another linkage has been incorporated that allows for fine adjustment of the bullet angle.

This means it can be run perfectly parallel to the beam, reducing the amount of drag and lowering fuel consumption.

Retail price is £8,495, including a removable light board.

Covenbrook

In a departure from the common beam design, Covenbrook’s trailed single-leg mole plough runs on twin-wheel rocking beam axles.

Benefits are that there’s less drag, meaning it can be pulled by a 150hp tractor, and there’s loads of space for trash to flow freely.

Any residues that might wrap around the leg are sliced ​​by a leading disc before they get there.

Working depth is adjusted simply by adding shims to the raise/lower ram and there’s a top link-style adjuster for setting the correct working angle.

Other features include a bracket to hold the ceramic expander out of harm’s way and a replaceable shin to eke more life out of the leg.

The plough is built at the firm’s farm near Braintree, Essex, and is priced at £10,995. A new twin-leg model is in development.

J Silk Agricultural

Hertfordshire engineer James Silk builds a compact single-leg mounted mole plough that’s designed to work with tractors from 120hp.

The enclosed beam format keeps surface disturbance to a minimum and features an integrated notched cutting disc that slices through turf or crop residues.

A twin-axis pivoting headstock allows the beam to float independently of the tractor over uneven ground, as well as turn through gentle curves.

Spring dampers on either side of the beam prevent the machine from swaying when lifted out of work.

And a carefully positioned hydraulic top ram can be used to influence how the machine pulls in and out of work.

Retracting it when starting the mole gives a steeper angle to reach the working depth in a much shorter distance.

Conversely, by fully extending it when pulling out of work, the bullet and expander will ride gently out of the ground.

Depth is adjusted using a pin-and-hole arrangement, and the angle of the bullet relative to the beam can be altered by adding and removing shims. Prices start at £8,935.

Philip Watkins

Philip Watkins builds both single- and twin-leg trailed mole drainers at its Yorkshire workshop, with the former also available in mounted format.

In all cases, these use a ground beam to maintain accurate moling depth, with a central disc to cut through trash and prevent it wrapping around the leg.

Bolt-on Hardox skids are fitted to save beam wear and there’s an adjuster for tweaking the angle of the bullet so that it runs parallel.

A toolbox and LED road lights are also standard fitment on all models.

Mounted models lift on the tractor linkage, while trailed versions use a hydraulic ram to put the machine in and out of work.

Prices start at £5,800 for a single-leg mounted plough, with single- and twin-leg trailed versions costing £8,800 and £15,000 respectively.

Proforge

Like several of the ploughs featured here, the MonoMole (single-leg) and MultiMole (twin-leg) machines from Proforge run on a beam with a centrally mounted disc to cut through trash.

The leg is also set back from the beam to give room for trash to clear, with depth settable in 1in increments and a pitch adjuster to get the bullet running level.

For added durability, there’s a full-length replaceable under-beam skid, which has a raised nose to prevent the front digging into the ground.

The firm uses high chromium steel for the front bevel plate and bullet, both of which are said to offer five to seven times the lifespan of regular parts.

Mounted machines use a floating top link that allows it to glide over undulating land.

Trailed versions have an adjustable height drawbar eye and a hydraulic ram for putting it in and out of work.

Power requirements range from 130hp for single-leg models to 350hp plus for the twin-leg trailed when pulled by a crawler, or 450hp behind a wheeled tractor.

Prices start at £7,650 for the mounted MonoMole and run to £16,950 for the trailed MultiMole.