AS/NZS 1080.2.4:1998

1 - AS/NZS 1080. 2.4: 1998 TIMBER - METHODS OF TEST - COMPOUND SLOPE OF GRAIN
1 - 1 SCOPE
1 - 2 PRINCIPLE
1 - 3 REFERENCED DOCUMENTS
1 - 4 DEFINITIONS
1 - Compound slope of grain
1 - 5 TEST PIECE
2 - 6 PROCEDURE
2 - 7 EXAMPLE OF CALCULATION
2 - 8 REPORT

Describes a method for calculating the compound slope of grain from slopes determined for two surfaces at 90 degrees to each other.

This Standard sets out the method for determining compound slope of grain in timber articles of which the backsawn (flat sawn) and quartersawn surfaces exhibit grain deviation from the axis of symmetry. This Standard is one of a number dealing with determination of slope of grain.Where the radial and tangential surfaces both show evidence of sloping grain, the true slope may be found to be greater than that on either surface. This compound slope of grain may become critical in pieces of small cross-section that are highly stressed, such as ladder stiles.NOTE: Where predictable strength of timber is the primary consideration, sloping grain can be an important characteristic. It is often difficult to detect by visual examination of the surface. The importance of the characteristic will be appreciated where it is realized that sloping grain means that a beam with sloping grain has a strength that may be significantly less than the strength of the wood fibre in the beam, e.g. there is a reduction in the strength of beams, from the fibre strength, of approximately 20 percent for a slope of 1 in 16, 30 percent for a slope of 1 in 12 and 50 percent for a slope of 1 in 8. Grading processes identify this reduction in performance.It is stressed that this test method determines only whether or not a piece of timber has slope of grain and its magnitude. It does not set down any criteria for grade specifications.

First published in Australia as AS 1080.2.4-1981.
Jointly revised and designated AS/NZS 1080.2.4:1998.