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Grades of Tas Oak
In general, dried and machined Tasmanian Oak produced for appearance
applications is graded to rules set by Australian Standard AS2796.2-1999:
“Timber-Hardwood-Sawn and Milled Products, Part 2: Grade
description” as a minimum allowable quality. This Standard
covers most milled timber products except window frames, sashes
and sills.
Tasmanian Oak is available in three grades; Select
(SEL), Medium
Feature - Standard (MF) and High
Feature (HF). Select grade timber is the most uniform
in appearance, while Medium and High Feature contain larger
amounts of natural feature such as gum, natural stains and knots.
Timber is generally graded on all faces.
Tasmanian Oak is usually sold free of sapwood, as it is susceptible
to attack by lyctid borers (although AS2796 allows inclusion
of sapwood treated with preservative). Burl or hobnail feature
may be present, as there is no limitation on them in any of
the grades. None of the grades contain timber with decay, compression
failures, shakes, splits or other fractures. Want, wane and
mechanical damage are permitted only on concealed surfaces.
Stains caused by processing (such as marks from racking sticks)
are only allowed in products that are to be painted.
All grades of timber are allowed the same amount of distortion;
this is governed by product type rather than timber grade. Thus,
a product of any grade can be expected to fit readily into its
intended application. However, flooring or light decking of
Medium or High Feature Grade may require knots or holes that
approach the maximum size allowed to be trimmed out.
A pack of timber of a particular grade will have a fair distribution
of boards with the amount of feature allowed in that grade.
Photographs of panels representative of each of the three grades
are presented on the following pages, along with a summary of
the maximum amount of natural feature allowed in each of the
grades. |
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