Wednesday, July 11, 2012

African Engineers: Green Cutlasses

In an age in which Greens preach more loudly than Christians it is fitting that popular Biblical quotations find new green expressions. In Ghana, grassroots engineers have reinterpreted Isaiah's vision of turning swords into ploughshares by turning worn out band-saw blades into farming cutlasses. Band-saws are used in Ghana's numerous sawmills to turn its mighty forest trees into wooden planks, but making cutlasses from the old blades is helping small farmers to feed themselves and their village communities. Although this activity does nothing directly to preserve the forests it does recycle precious imported material and preserve it for use in a greener setting.

Band-saw blades are made of specially formulated carbon steel that combines the properties of hardness with flexibility and shock resistance. The metal can provide a sharp and durable cutting edge with the capability to run bent around steel rollers in a continuous loop. According to veterans of the sawmilling industry, all that these blades cannot survive is meeting a large rock that has been carried up by the tree as it grew and become embedded deep within its enormous trunk. Needless to say, steel of this quality is ideal for farmers' cutlasses used for weed control and clearing scrub.

In informal industrial areas, or kokompes, like Suame Magazine in Kumasi, a cutlass maker's workshop is identified by a pile of old band-saw blades lying nearby. The conversion process is really hard work. The material is so hard that it can be cut only by a hammer and chisel. The sharp cutting edge of the chisel can survive only a few blows before it needs re-sharpening and this is effected with the aid of an electric grinding machine, usually mounted on an old wooden bench. By this arduous process the outline of the cutlass blade emerges from the flat steel sheet of the old band-saw blade.

The shape of the cutlass blade includes the outline of the handle. Two holes are punched to allow a wooden handle to be held in place by rivets. The two wooden parts of the handle are usually made by a carpenter and supplied ready shaped to be fixed by the cutlass maker. With a wooden half-handle placed on each side of the steel blade, holes are drilled through the wood and the three-part sandwich is held firmly together by two steel rivets. The cutlass is finished by sharpening the cutting edge on the same grinding machine used for re-sharpening the chisel. When well crafted, as many of them are, the locally made cutlasses are of comparable appearance and effectiveness as imported models.

The high priests of the green movement would like to see the complete preservation of the tropical forests. This would entail the cessation of logging, the closure of sawmills and the eventual demise of the local grassroots cutlass industry. Ghana's farmers would become dependent on imports, or local production based on imported material, for all of their cutlasses. No doubt, set against the larger green aspiration, this sacrifice would be easily made.



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