Level 1 Diploma in Carpentry and Joinery

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Timber conversion

Unit 115: Produce woodworking joints

Level 1 Diploma in Carpentry and Joinery

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Aims and objectives

Aim:Introduce learners to timber conversion.

Objectives:• Identify at least two methods of timber conversion.• Sketch through-and-through timber conversion.• State the method of conversion for carcassing timber.

Level 1 Diploma in Carpentry and Joinery

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Timber conversionThe way the cuts are made will depend on several factors, including: • The type of sawing machine.• The size of log (diameter of girth).• The condition of the log.• The wood species.• Economy.• The end use of the resulting timber – for its appearance, decorative or structural requirements.

Level 1 Diploma in Carpentry and Joinery

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Timber conversion

The resulting timber section (with the exception of that which surrounds the pith-heart) will be either:• Plain or tangential sawnor• Quarter or rift sawn

Level 1 Diploma in Carpentry and Joinery

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Through-and-throughLarge logs can be quickly converted in this way. It is cheap in comparison to other methods. The resulting timber will be part plain sawn and part quarter sawn.

Pith or heart

Level 1 Diploma in Carpentry and Joinery

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Quarter (radial) or rift sawnQuarter or rift sawn can be wasteful and expensive, but is necessary where a large number of radial, or near radial, sawn boards are required. Certain hardwoods cut in this way can produce beautiful figured boards, eg oak.

Quarter sawn boards retain their shape much better than plain sawn boards and will shrink less in service, making them suitable for good class joinery work and quality decking for floors.

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Quarter (radial) or rift sawn

Pith or heart

Level 1 Diploma in Carpentry and Joinery

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Tangential sawn• Logs cut in this way will, with the exception of the heart

(centre portion of the log) section, provide timber with a tangential face.

• This method of conversion is used when cutting up large diameter logs of hardwood or softwood.

• Timber produced by this method has a structural strength which makes it ideal for use as beam or floor joists.

• Boards produced by this method of sawing are also likely to shrink a great deal.

Level 1 Diploma in Carpentry and Joinery

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Tangential sawn

Pith or heart

Level 1 Diploma in Carpentry and Joinery

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Aims and objectives

Aim: Introduce learners to timber conversion.

Objectives:• Identify at least two methods of timber conversion.• Sketch through-and-through timber conversion.• State the method of conversion for carcassing timber.

Level 1 Diploma in Carpentry and Joinery

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Any questions?