Over the last few days I started to get ready to be able to take a crop of hay. The last time we did this we had major problems – when we were on the last small field the power scythe blade appeared to jam and stop working. We tried, with limited success, to get the remainder of the field by hand but this really didn’t work and I needed the power scythe working before the end of the month. The grass has been growing well and looks like a fair crop, we have to be ready should there be a dry sunny period long enough to do the work.
The power scythe is an implement which attaches to the front of our two wheeled Goldoni tractor. It is quite expensive so buying a new one is not a prospect I wanted to consider. The companies who sell these machines are keen to sell the kit but, I discovered, much less keen to get involved in repairs so it was down to me to get it working again. I had the instruction manual so what could go wrong ?
Firstly, the manual itself could throw an obstacle in my path. These machines are made in Italy (the small farms and olive groves make two-wheeled tractors popular there) and the manuals likewise. Thus my manual was written in Italian which made the first step an attempt to decode the booklet. It had few diagrams or schematics to ensure that there were no unnecessary visual clues.
Over two days I, with the help of a neighbour, stripped the machine down to all its constituent parts. We inspected and cleaned every piece and then reassembled the machine checking all the settings with feeler gauges to the millimeter. With new grease and oil the machine moved smoothly with no jamming or hesitation. We hooked it up to the tractor and proudly set forth into the field for a celebratory and confirmatory cut of some long grass. It cut smoothly and effortlessly through the sward for about a yard then jerked and the sickle blade seemed to seize. No further cutting was possible. No amount of rocking, shaking, cajoling or threatening, coaxed even an inch of movement from the machine’s teeth.
Back in the barn we disassembled the blade to see where we had gone wrong. This is not a fun job. The piece weighs about 80kg, is oily and slippery and has two rows of menacingly sharp iron teeth. I have seem those teeth slice effortlessly slice though the legs of an iron park bench – it is no fun to handle! After having looked everywhere there was no sign of any jam. No sign of anything that could block the transit of the blades. The problem had to lie in the connection between the power unit and the appliance but we had checked this twice. In additon we had checked with two other appliances to be doubly sure that the transmission linkage worked properly.
While we had the machine upside down we noticed a small hole and wondered what is that for. Peering in we could see nothing of note, just black think molybdenum grease. Five minutes later, after poking our fingers down the shaft and pulling out all the grease we could, we were able to see a small circlip around the drive shaft. As we rotated the drive shaft we saw that this was held in place by a small set screw – a small grub screw about 3mm across with a hexagonal allan key head. We checked and this grub screw was loose so we tightened it up.
We realized that when slack this grub screw would not stop the driving spline from being pushed back just far enough to allow the connection between the power unit and the scythe to be lost – the two connecting faces would no longer be sufficiently close to carry the power down to the blade and instead they would just bump over each other. After tightening up the screw we powered up and returned to the field where the unit ran perfectly. We cut grass, tried on an area of brambles, and pushed over rocky ground and through dense scrub – it didn’t waver. It just ploughed on cutting as it went, it was well and truly fixed.
This episode taught me a two lessons. Firstly, be careful no to jump to conclusions. Had we spent more time at the beginning thinking about the problem we might have realized the problem lay further back in the chain from power unit to cutting blade. We might have saved ourselves a lot of work. However, I am glad I have dismantled and serviced the machine, it needed it anyway, and I feel much better knowing exactly how it is made and how it works. Even when we did realize the problem was to do with the power take off it would have taken us a while to find this small screw that appears no where in the manual.
The second lesson is perhaps more important. I often wonder if there is any point in trying to be green in my daily life as I try to reuse and recycle. I wonder if my attempts to reduce my consumption make any great difference. What does my level of consumption matter in the greater scale of things. On a wider basis I wonder if it makes any point that I, as a fairly insignificant and powerless individual, try to do my bit for a better society – can one person make a difference ?
This little grub screw was only about 0.0001% of the metal parts of the mowing machinery; of the parts it clearly was the “least of these“. Hidden down a shaft in the bowels of the machine, in the dark, covered in oil and grease this little screw had slackened off, stopped doing its job, and the whole hay making project shuddered to a halt. In the interconnected system it lived within it was as valuable as any other. And so it is with all of us. We might often feel small and powerless in comparison to our rulers, or the celebrities we see daily, but we all play our part and it may be our part which proves to be the vital step in how things change.