Understanding Wood: A Craftsman’s Guide to Wood Technology

292 Pages·2000·22.53 MB·English

by  R. Bruce Hoadley

Completely Revised and Updated
Understanding
Wood
A CRAFTSMAN’S GUIDE TO
WOOD TECHNOLOGY
R. Bruce Hoadley
$39.95 U.S.
Understanding
Wood
A CRAFTSMAN’S GUIDE TO
WOOD TECHNOLOGY
“Clearly the best book available on the subject.”
—Wooden Boat
Understanding Woodanswers every woodworker’s
question:Why does wood do what it does? Updated
to include new information on composite materials,
adhesives,and finishes developed in the past
20 years,this completely revised classic has every-
thing you need to know about wood technology.
R.Bruce Hoadley,reknowned wood technologist,
explores the nature of wood and its properties,the
basics of wood technology,and the woodworker’s
raw materials.You’ll learn the best ways to cut,
season,machine,join,bend,fasten,and finish wood,
and explore the crucial interaction of wood and
moisture.You’ll also find the latest on wood prod-
ucts and where to buy them.
Everyone who works with wood—craftsmen,
builders,engineers,and designers—should own this
completely revised version of the classic
Understanding Wood.
Understanding
Wood
A CRAFTSMAN’S GUIDE TO
WOOD TECHNOLOGY

Understanding
Wood
A CRAFTSMAN’S GUIDE TO
WOOD TECHNOLOGY
R. Bruce Hoadley
t
Cover photographer: Randy O’Rourke
Publisher: 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 [bottom], 90, 91, 93 [top left], 113, 135, 155, 169 [right], 174, 215 [top])
Pp
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.
Illustrations by Mario Ferro © 2000 by The Taunton Press, Inc.
All rights reserved.
Printed in the United States of America
10 9 8 7 6
The Taunton Press, Inc., 63 South Main Street, PO Box 5506, Newtown, CT 06470-5506
e-mail: [email protected]
Library of Congress Cataloging-in-Publication Data
Hoadley, R. Bruce.
Understanding wood : a craftsman’s guide to wood technology / R. Bruce Hoadley.
p. cm.
Includes bibliographical references and index.
ISBN: 978-1-62710-158-5 (eBook)
ISBN: 978-1-62710-159-2 (ePub)
ISBN: 978-1-62710-160-8 (mobi)
ISBN: 978-1-62113-171-7 (fixed)
1. Woodwork. 2. Wood. I. Title.
TT180.H59 2000
684’.08—dc21 00-044322
About Your Safety
Working wood is inherently dangerous. Using hand or power tools improperly or ignoring safety practices can lead to
permanent injury or even death. Don’t try to perform operations you learn about here (or elsewhere) unless you’re certain
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 Côté 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 Aimé
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
Foreword 4
Part One
The Nature of Wood and
Its Properties Bending theory 87
The carrying capacity and stiffness of beams 90
1 The Nature of Wood 6 Factors affecting strength properties 94
Growth rings 10 Compression failures and brashness 99
Grain 10 Structural grades 100
Sapwood and heartwood 11
5
Structural arrangement of growth Other Properties of Wood 102
rings and rays 12 Thermal conductivity 103
Density and specific gravity 14 Effect of temperature on wood 104
Systematic classification 16 Burning of wood 104
Cellular structure 17 Fluorescence 105
Softwoods 18 Psychological properties 107
Hardwoods 20
6
Water and Wood 110
2
Figure in Wood 24 Free water and bound water 112
Knots 32 Equilibrium moisture content 112
Abnormal wood 36 Green vs.air-dried vs.kiln-dried 114
Fungi 40 Dimensional change in wood 116
Insect damage 44 Estimating shrinkage and swelling 118
Uneven shrinkage and swelling 123
3
Wood Identification 46
What to look for 50 Part two
Basics of Wood Technology
Physical properties 52
Identification techniques 52
7
Macrophotographs 55 Coping with Dimensional Change
in Wood 132
4 Strength of Wood 74 Preshrinking 133
Compression parallel to the grain 78 Control of moisture sorption 133
Compression perpendicular to the grain 80 Mechanical restraint 134
Tension perpendicular to the grain 83 Chemical stabilization 136
Tension parallel to the grain 84 Design 139
Shear perpendicular to the grain 85 Monitoring moisture 141
Shear parallel to the grain 85 The moisture “widget” 145
8 Part three
Drying Wood 146
The Woodworker’s Raw Materials
How wood dries 148
The dry kiln 149 13
Lumber 212
Drying your own wood 151
Lumber measure 216
Storing lumber 156
Lumber classification and grading 218
9
Machining and Bending Wood 158 14
Veneer and Plywood 224
Machining wood 159
Plywood 229
Bending solid wood 177
Classes of plywood 230
10
Joining Wood 180 15
Composite Panels 234
The elements of joints 181
Particleboard 235
Basic types of joints 183
Wafer- and strand-based panels 236
Worked joints 183
Fiber-based panels 236
Fastened joints 188
16
11 Engineered Wood 240
Adhesives and Gluing 192
Finger-jointed lumber 241
Adhesive joints 193
Glulam 242
Gluing fundamentals 194
Structural composite lumber 243
12 I-joists 244
Finishing and Protecting Wood 198
Surface condition 199 17
Finding Wood 246
No treatment 202
Trees 247
Coating treatments 205
Recycling used wood 249
Penetrating finishes 206
Local sawmills 250
Combinations and compromise 207
Lumberyards 251
Slowing moisture exchange 207
The woodworkers’retail outlets 252
Evaluation of finished surfaces 209
Industrial arts teachers 253
Preservative treatment of wood 209
Magazines 253
Specialty woods 253
The Yellow Pages and other listings 253
Internet 253
Lumbermen 253
Afterword:Forests past and future 254
Appendix 1:Commercial names for lumber 257
Appendix 2:Finding the specific gravity of wood 260
Glossary 262
Bibliography 272
Index 275