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a) State two methods of converting round logs into commercial sizes.
b) Describe the most suitable method of producing oak boards for decorative and stable tabletops.
(a) Methods of converting round logs into commercial sizes.
Through & Through
Through & Through Little thought is given to the use of the timber (Plain, Flat or Slab sawn) and consequently it is used mainly for softwoods. The method is cheap and some boards are wide, but outer boards tend to warp (or cup).
Tangential Sawn
Tangential sawn or round the log here each time a board is removed the log is rotated 90 degrees then another board is removed. These 'tangential' boards are generally stronger as the annual rings are longest on the face of the boards. Also this type of conversion creates attractive grain patterns on the face of the boards as shown here on this European Walnut sample.
Small Timber logs
Small Timber Logs As the average size of a softwood log which will be used in a Swedish or Finnish saw mill is in the order of 300mm then fancy sawing techniques are irrelevant. usual practice is to take two or three large (225-250mm) pieces out of the centre and narrower side or edge boards from round the sides.
Quarter Sawn
Quarter Sawn used predominantly for hardwoods where stability (and in some cases madullary figure is required as shown here on this Japanese Oak sample). Quarter sawing is expensive in production time and also in the waste produced but boards are more stable, shrink evenly and generally stay flat.
The sample shows the medullary figure, light sapwood to the right and darker heartwood to the left
b) Describe the most suitable method of producing oak boards for decorative and stable tabletops.
Well Seasoned Quarter Sawn Boards will produce a very stable table top. Although the boards are nor generally very wide. If wide boards are needed for the table top then consider second seasoning tangential sawn boards.
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