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Materials Technology wood. Week 8 – lesson 2. Homework. Felling. Felling is the harvesting or cutting down of timber. Trees are usually cut down in the autumn and winter. Although they can be cut down in summer there are two main advantages to winter felling What are they?.

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materials technology wood

Materials Technology wood

Week 8 – lesson 2

felling
Felling

Felling is the harvesting or cutting down of timber.

Trees are usually cut down in the autumn and winter. Although they can be cut down in summer there are two main advantages to winter felling

What are they?

conversion of timber
Conversion of timber

After the tree is felled, the branches stripped off and the logs cut to size the logs are transported to the sawmill.

What happens at the sawmill?

methods of conversion
Methods of conversion:

The way in which logs are cut will affect the appearance and strength of the board.

The three main methods are....

Through and through sawing

Quarter sawing

Tangential sawing.

slide7

Through and through sawing

Very popular form of conversion. The logs are cut in parallel cuts in the direction of the grain.

Sketch this

slide9

Advantages:

  • Cheapest form of conversion.
  • Very little waste, maximum amount of timber is obtained.
  • Machining is straightforward reducing labour costs

Disadvantages:

  • The timber shows no particular grain pattern
  • This method of sawing is not suitable for structural timber
  • With this method cupping of the timber is a problem
quarter sawing
Quarter sawing

Sketch this

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Advantages:

An attractive grain pattern is obtained

These boards are more stable and shrink less

The timber wears more evenly. This is important in flooring, for example.

Disadvantages:

There is a lot more work needed in the machining of the log as it has to be turned for each cut

More expensive.

tangential sawing
Tangential sawing:

Sketch this

The cut is taken tangential to the annual rings.

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