AS/NZS 1080.2:2006 (R2016)
$20.15
Timber – Methods of test – Slope of grain
Published By | Publication Date | Number of Pages |
AS | 2006-06-07 | 13 |
Scope
This Standard sets out four test methods for determining the slope of grain in timber articles, as follows:
(a) The timber articles are either regular or irregular in plan or section, by means of a scribe (Clause 4).
(b) The timber articles are either regular or irregular in plan or section by reference to checks appearing on the surface (Clause 5).
(c) The timber articles are either regular or irregular in plan or section by the removal of splinters from the surface (Clause 6).
(d) The backsawn (flat sawn) and quartersawn surfaces of the timber articles exhibit grain deviation from the axis of symmetry (Clause 7).
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 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% for a slope of 1 in 16, 30% for a slope of 1 in 12 and 50% for a slope of 1 in 8. Grading processes identify this reduction in performance.
It is stressed that the test methods herein determine only whether or not a piece of timber has slope of grain and its magnitude. The methods do not set down any criteria for grade specifications.