Peterson Portable Sawmills

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Peterson Portable Sawmills

By Dr Garth Cambray

Placing the power of processing timber in small producers' hands, the sawmill invented by Carl Peterson is featured as this month's bush mechanic invention.

In past issues of Science in Africa we have run articles on timber in which have shown that in Africa, the focus in much of the continent is on extracting timber and removing it from the continent. In this way, a scarce resource is harvested by multinational companies using imported, expensive machinery, to export timber to the rest of the world. Often, timber leaves as unprocessed logs, which are processed in other countries - Africa's loss is somebody else's gain.

One of the greatest problems in forestry operations is timber extraction.

One of the greatest problems in forestry operations is timber extraction. The Peterson saw, the original portable swing blade saw overcomes this problem, by being transportable to the actual tree. Hence, a number of small operators can process timber in the forests, and leave the waste wood there, to contribute back to the environment and remove only the timber which is marketable.

In my experience, we have operated a Peterson swing blade saw for 5 years in an unskilled labour environment similar to that in the rest of Africa. The saw has operated for thousands of hours and the only maintenance required has been done by unqualified people.

How does the saw work and who invented it? Carl Peterson, the inventor of this technology which puts the power of processing timber in the small producers hands, was faced with conditions similar to those in much of Africa - lots of trees, and no resources. Through a process of gradual invention and extreme persistence he created many saws which advanced the concept of a portable swing blade saw.

How does the saw work? A large tungsten carbide tipped circular saw blade is fitted on a platform with an engine to power it by transferring power via a fan belt to a gear box to the saw blade. The saw blade is mounted on a platform that allows the blade to be either vertical or horizontal. The platform is mounted on small wheels which run on a railing which is paced on each side of the log to be cut.

The saw is started, and the platform lifted to an appropriate height using a number of pulleys all connected to one handle. The saw is aligned on the platform and pushed forwards with the blade oriented horizontally through the log and then returned with the blade orientated vertically. The result - you can cut a tree up into a series of pieces - the edge piece will be uneven on one side, the rest, until the other edge, will be rectangular pieces. The dimensions are chosen by the operator based on how deep the blade cuts into the wood.

Straight forward and very simple, but very practical.

Science in Africa salutes Carl Peterson as a bush mechanic who invented something that places power in the hands of the people, and then went on to commercialise this technology and provide the support that allows the technology to make a difference!

(And just in case anybody wants to know, we have run this sawmill on alcohol distilled from pineapples blended with 10% petrol. The Kohler motor operated perfectly acceptably).

More information:

www.petersonsawmills.com

Related articles:

Tree logging - the only way is up

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June 2006	Feature

Feature