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RYBINSK FOREST TECHNICAL COLLEGE


Evolution of my professional equipment:
yesterday, today, tomorrow.

Выполнил ТИХОНОВ в. 3 КУРС

SAWS
AND
THEIR DEVELOPMENT

YESTERDAY

Long ago the first saws were made of very hard stones. They served for the shaping of wood when making ornaments.

YESTERDAY

Large saws to fell trees could not be made until hard metals and alloys were obtained.
For centuries the sawing of logs had to be done by hand-power with huge pitsaws. Two men drew the great blade up and down.

YESTERDAY

From 1420 people began to apply the power of water miles to force the heavy pit-saw move.

YESTERDAY

From 1781 saw millers began to saw up logs with circular saws. Sharp teeth were cut round the edge of a round metal plate which was revolved on a spindle.

YESTERDAY

From 1808 a new kind of saws was patented. It was a band saw with teeth set on one edge of an endless metal band, revolving round two wheels.

YESTERDAY
From 1930 hand saws have been replaced by the petrol driven chain saws which work on an entirely different, principle. Instead of a flat blade with sharp teeth being drawn to and fro, an endless chain of teeth is propelled here round a fixed guide-blade. Lange sharp teeth quickly tear out chips of wood.

YESTERDAY

TODAY
Nowadays all saws are made of steel. Most kinds of saws are designed to work either across the grain or with it. But it is possible to saw logs ignoring the grain as well. The design of all modern saws enables them to make a narrow gap through the log with great accuracy and minimum waste of wood.

Modern petrol driven chain saws

Modern band saws

Modern circular saws

TODAY
Harvester is a logging machine that cuts down the trunk of a tree, then cleans it from knots, cuts it into elements according to grades, and then distributes these parts in one-size packs. The main disadvantage of the harvester is its high price and expensive parts.

TODAY

tomorrow
In future, we hope many loggers will have these machines as Harvester and Forwarder.



These logging machines free man’s hands from hard and monotonous labor. A man no longer depends on power of his own muscle. Moreover, introducing automatization at each working place provides the conditions for highly productive efficient labor.