A Fahr MD4 combine was a huge attraction at the De Courcey vintage harvest event in August of last year.

Its owner, Derry Desmond, of Kinsale, Co. Cork, kindly invited Agriland to take a closer look at the machine.

Dating from 1954, it is one of only two examples known to have been imported to Ireland, and there is no record of what happened to the other.

They were brought in by McGee Stores of Ardee, Co. Louth with this particular example going to a farm in Co. Kilkenny.

Tax disc on combine — The combine was last taxed for road use in 1963

From there, it was traded in for another combine at Kearney’s of Fermoy – where it stood outside for several years, before being purchased by a collector from Buttevant, Co. Cork.

It was kept in a shed, which is where Derry Desmond came across it around 10 years ago.

Returning it to working order involved a lot of work, although, only being a small machine by today’s standards, it was quite manageable.

Two of the major issues he encountered were seized chains and rotted belts.

He was able to free up the chains while replacing the belts. He was able to do so with the help of a local engineering company which gave him a box to sort through.

Derry Desmond delights in showing people around the Fahr MD4

He didn’t touch the steelwork, as it was still perfectly sound despite being 70-years-old, and having spent years exposed to the elements.

Derry puts this firmly down to the quality of the steel, and compares it to a later addition to the combine – which is the rear hood.

Crop considerations

Unfortunately, the baler has long since disappeared, but a spiral crop divider still exists – albeit in a rather forlorn condition.

This ran up the right-hand-side of the table, and was presumably there to deal with taller crops in the days before semi-dwarf cereal varieties.

Dynamo on MD4 — Unfortunately the unusual twin pully dynamo has recently given up, finding someone to service it is proving difficult

The engine is a diesel unit said to be of 48hp, but it is not all clear as to who made it. There are two likely candidates, Hatz and Hanomag.

Henschel has also been suggested but the company did not produce any engines itself until its merger with Hanomag in 1964.

As it stands, there is no indication on any of the castings, other than a stamped serial number and the cylinder numbers boldly cast into the block.

Powering a thresher

In the early days, combine harvesters were seen as little more than mobile threshing machines – something which had been made possible by the advent of the compact internal combustion engine.

However, the problem that had still not been solved was where to put it. Fahr’s solution was to bolt it to the lower left-hand-side, behind the front axle, where it would have kept the centre of gravity low.

MD4 engine — Manufacturer unknown, however most would agree that it is a 48hp model

In this position, it was also central to most of the moving parts such as the drum, sieves and the single-straw walker.

Drive to the header was by belt and chain, and drive to nearly everything else is by a convoluted series of shafts, belts and gears.

It is this collection of very well-engineered, but rather complex drivetrains, that sets the character of the Fahr MD4 apart from other combines from the 1950s.

Front of combine — Pointing the rear wheels in the desired direction involves a lot of engineering, starting with a worm gear at the steering wheel

The steering wheel turns a worm gear, which then rotates a cross shaft running to the right-hand-side of the machine.

This turns a chain running to the lower rear of the body, where it activates a pivot point which pushes or pulls at a steering arm mounted on the left-hand wheel.

Yet another rod then transfers this motion to a steering arm on the right. It all works perfectly well, but it does give the suggestion of being an afterthought rather than an integral part of the harvester.

It’s as if the company built a small thresher, and then added the working components to make it mobile as they thought of them, rather than take a more holistic approach.

Bagging conveyor — The bagging station had four outlets, enabling two men to work it. The handle in the bottom right adjusted the fan pressure

These were early days for combines, so this sort of experimentation only adds to the charm and appeal of this exercise in engineering. Derry confesses to being rather fond of its idiosyncrasies.

Making the MD4 move

Another notable feature is the transmission. This is believed to be a ZF unit, but Derry has not yet had to delve deep enough to confirm this, and there is no immediate indication when looking at it in situ.

There are five forward ratios and a reverse, which, in the absence of an infinitely variable transmission, gives a good range of speeds for a slow machine.

Just how low first gear is remains an unknown for it cannot be selected at present and is one of those jobs that will require the eventual removal of the transmission.

MD4 with modern combine in background — Even with nearly 70 years between them, the lessons learnt in the early days still apply to modern machines

As an early attempt at creating a combine harvester from scratch, the Fahr MD4 is a fascinating window into the challenges faced by engineers as they strived to create a new class of machine.

It is tempting to consider experimental machines, but the MD models were mass-produced.

The last of the line, the MDL, stayed in production up until 1964 – although the engine had by then been moved to behind the driver’s seat, as is standard practice today.

Also Read:
Machinery: Harrow and roll in one pass this spring

DeCourcey

Machinery Focus: A closer look at the Fahr MD4 combine