Understanding wood : a craftsman's guide to wood technology

293 Pages·2000·67.59 MB·English

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UNDERSTANDING
WOOD
UNDERSTANDING
WOOD
R. Bruce Hoadley
NEPTUNE
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The Taunton Press
Cover photographer: Randy O'Rourke
Publisherr: James Childs
Associate Publisher: Helen Albert
Associate Editor: Jennifer Renjilian
Copy Editor: Diane Sinitsky
Indexer: Pamela S. Venneman
Cover and Interior Designer: Mary Skudlarek
Layout Artists: Mary Skudlarek, Rosalie Vaccaro
Illustrator: Mario Ferro (pp. 18,20,53,86 [bot tom] , 90,91,93 [top left], 1 13,135,155,169 [right], 174,215 [top])
The Taunton Press
Inspiration for hands-on l iv ing
Text © 2000 by R. Bruce Hoadley
Photographs by Randy O'Rourke, Richard Starr, Charley Robinson, Alec Waters, and Vincent Laurence
© 2000 by The Taunton Press, Inc.
Il lustrations by Mario Ferro © 2000 by The Taunton Press, Inc.
All r ights reserved.
Printed in the Uni ted States of America
1 0 9 8 7 6 5 4 3 2
The Taunton Press, Inc., 63 South Main Street, PO Box 5506, Newtown , CT 06470-5506
e-mail:
To my family—
my wife, Barbara, and my daughters, Susan and Lindsay—for understanding.
ACKNOWLEDGMENTS
As I stated in the first edition, the idea and approach for a wood specimens for photography. I am also indebted to
book of this type came originally from the many students I Cowls Building Supply, Inc., of North Amherst,
have worked with over the years, especially those in craft Massachusetts, for its contribution of lumber items for pho-
workshops, short courses, and seminars. Their many ques- tography and for permission to take photographs at its store
tions, discussions, reactions, and frequent suggestions to put and mill.
it all down on paper were the impetus to get me started. For Much of the technical data on physical and mechanical
his encouragement to begin the writing and for his support properties of wood as well as some of the illustrations were
throughout the first edition, I owe special thanks to Dr. reproduced or adapted from the Wood Handbook and other
Donald R. Progulske, head of the Department of Forestry publications of the U. S. Forest Products Laboratory at
and Wildlife Management at the University of Madison, Wisconsin. During visits to the laboratory and in
Massachusetts, Amherst. Twenty years later, in considering correspondence, members of the staff were always helpful
a second edition I again was pleased to have the strong sup- and cooperative.
port of Dr. William McComb, current head of our depart- During the early stages of production, my daughter
ment, now renamed the Department of Natural Resources Lindsay gave me the long hours of assistance needed in
Conservation. proofreading the scanned text of the first edition. She was
Teaching is in itself an education, and since the first edi- also my personal editor when I needed help with grammar,
tion, meeting with students in my classes has helped me to when an awkward sentence needed rewriting, or when a
rethink, revise, reshape, and update many of the fundamen- complicated paragraph needed rearranging. A major feature
tals of the book and the way I present them. I thank my stu- of the second edition is the color photography, for which
dents once again for their role, even though they may not Randy O'Rourke accomplished his camera magic with ded-
realize the important feedback they have provided. My fac- ication and patience and brought life to the many wood
ulty colleagues and close friends, Paul Fisette, David specimens and objects. Randy's photographs blend nicely
Damery, and Dr. Stephen Smulski, have been a continuous with many taken previously by Richard Starr and Brian
source of information, always willing to share their expert- Gulick. Once again, the electron micrographs by Wilfred
ise. Emeritus faculty of our department, Dr. Alan A. Marra Cote are an important piece to understanding wood,
and Dr. William W. Rice, have also contributed critical An author discovers that a book could not materialize
information for this second edition related to their respective without extensive professional support. Among the many
specialties of wood adhesives and wood drying. Daniel that made this edition a reality were consulting editors Aime
Pepin was invaluable in locating and machining many of the Fraser and Diane Sinitsky, and Jennifer Renjilian, Carolyn
Mandarano. and Lynne Phillips at The Taunton Press.
CONTENTS
preface 3
Forword 4
PART ONE
THE NATURE OF WOOD AND
ITS PROPERTIES Bending theory 87
The carying capacity and stifnes of beams 90
1 The Nature o f Wod 6 Factors afecting strength properties 94
Growth rings 10 Compresion failures and brashnes 9
Grain 10 Structural grades 10
Sapwod and heartwod 1
Structural arangement of growth 5 Other Properties of Wod 102
rings and rays 12 Thermal conductivity 103
Density and specific gravity 14 Efect of temperature on wod 104
Systematic clasification 16 Burning of wod 104
Celular structure 17 Fluorescence 105
Softwods 18 Psychological properties 107
Hardwods 20
6 Water and Wod 10
2 Figure in Wod 24 Fre water and bound water 12
Knots 32 Equilibrium moisture content 12
Abnormal wod 36 Gren vs. air-dried vs. kiln-dried 14
Fungi 40 Dimensional change in wod 16
Insect damage 4 Estimating shrinkage and sweling 18
Uneven shrinkage and sweling 123
Wod Identification 46
What to look for 50 PART TWO
Physical properties 52 BASICS OF WOOD TECHNOLOGY
identification techniques 52
Macrophotographs 55 7 Coping with Dimensional Change
in Wod 132
4 Strength Of Wod 74 Preshrinking 13
Compresion paralel to the grain 78 Control of moisture sorption 13
Compresion perpendicular to the grain 80 Mechanical restraint 134
Tension perpendicular to the grain 83 Chemical stabilization 136
Tension paralel to the grain 84 Design 139
Shear perpendicular to the grain 85 Monitoring moisture 141
Shear paralel to the grain 85 The moisture "widget" 145