features
#010 / 1998

technical report review

Machining And Related Mechanical
Properties of 15 BC Wood Species

by Derek Williams and Roman Morris

This soon-to-be-released Forintek report manages to challenge and support the status quo in BC secondary wood product manufacturing. It challenges the industry with data that sometimes shows unexpected results. For example:

  • Aspen has superior planing properties to Douglas-fir
  • Larch comes second only to birch in screw holding ability
  • Western white pine is unrivaled for shaping/moulding
  • Using a brad point bit, hemlock bores a cleaner hole than alder
  • At a high feed rate, cottonwood planes better than western red cedar
  • Hemlock is a mediocre choice for turned components

These random highlights of the professionally researched and well-presented report are gleaned from chapters that detail planing, sanding, boring, mortising, shaping, turning and fastener-holding capabilities. Each section includes the procedures, equipment and ASTM (American Society for Testing Materials) test used (some custom adapted) and provides the results in convenient table format.

Where the report is less challenging and toes the traditional industry line is in its basic parameters and chosen range of technologies. For example, the test samples' moisture content level was set at 12% (softwoods) and 9% (hardwoods), the "typical" standard, according to the report. When furniturelink asked Bob Bird (vice-president, Canwood Furniture, and FRBC committee member) to comment he said that in addition to the 12% levels, tests should also have been made at furniture industry standards (8-9%) and measurements taken to gauge the effect of kilning/drying quality on the data.

Other aspects of the report that reflect traditional industry attitudes are:

  • Only HSS used for knives and drills
  • RTA hardware and staples not included as fasteners
  • No tests using CNC based machinery

In its conclusion the report makes recommendations for further studies, including a study of gluing and finishing properties. Designers/makers would certainly support such a study.

It is hoped that Forintek will consider value-created manufacturing when setting parameters for future studies and not restrict access to important technical information because of the way a particular sector defines wood products manufacturing.

(The report is available from Forintek.)

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© furniturelink 1998 (text and images)