Wooden box and crate construction

Front matter

O M O >^*

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Introduction

The Forest Products Laboratory is a research unit of the Forest Service, U. S. Department of Agriculture. It is located at Madison, Wisconsin, where it was established in 1910 in co-operation with the University of Wisconsin. Its purpose is to acquire, disseminate and apply useful knowledge of the properties, uses and methods of utilization of all forest products and thereby to promote economy and efficiency in the processes by which forests are converted into commercial products. In this work 220 research technologists are employed. Its field of investigations and activities embraces :

1. Obtaining authoritative information on the mechanical and physical properties of commercial woods and products derived from them ;

2. Studying and developing the fundamental principles underlying the seasoning and kiln-drying of wood, its preservative treatment, its use for the production of fiber products (pulp, paper, fiber board, etc.). and its use in the manufacture of alcohol, turpentine, rosin, tar and other chemically derived products ;

3. Developing practical ways and means of using wood which, under present conditions, is being wasted ;

4. Co-operating with consumers of forest products in improving present methods of use ; also in formulating specifications and grading rules for commercial woods and materials obtained from them, and for material used in the preservative treatment of wood ; and

5. Making the information obtained available to the public through publications, correspondence, and by other means.

Commercial research and mechanical tests on containers were begun in 1915 in co-operation with the National Association of Box Manufacturers, the National Canners' Association, and the National Wholesale Grocers' Association. Methods of testing and testing equipment were developed which have since become more or less standard for the box industry. From the data accumulated by the laboratory, the War Department prepared during the war general specifications for overseas containers. At the laboratory in Madison, many containers to be used for the shipment of war equipment were tested and redesigned along more economical lines, including increase in strength, decrease in amount of material required, decrease in cubic contents and a consequent reduction of ocean freight costs.

Since the war the laboratory has co-operated with many associations and companies in testing and studying the construction of many different types of containers such as those used for the shipment of electric lamps, cream separators, small tractors, talking machines, boiler castings, furniture, paints and oils, piano benches, fruit baskets and crates, and shoes.

Contents

Page

Publisher's iNXRonucxiON v

I NTRODUCTION vii

List of Tables xiv

List of Plates xiv

List of Figures xv

CHAPTER I Use of Wood in Box and Crate Construction

Adaptability 1

Availability 1

Cost : 1

Salvage value 1

Qualities 2

Desirable qualities 2

Kinds and Amounts of Lumber Used 2

The choice of species . . ." 2

Amount of each kind of lumber used 3

Consumption of box lumber by States 3

Distribution of box lumber 5

Commercial Grades and Sizes of Lumber Available for Box

Construction 8

Standard Defects and Blemishes in Lumber 8

Grading According to Size of Lumber •. . . 10

Standard sizes of lumber 10

Grades suitable for boxes and crates 11

Important Physical Properties of Wood Which Influence Its Use

IN Box Construction 14

Weight 14

Importance 14

How the weight of lumber is expressed 14

Factors Which Influence the Weight of Lumber 14

Species 14

Density, or amount of wood substance 15

Resin content 15

Importance 15

How determined 15

Variation 16

How the moisture is contained in wood 16

Proper moisture content of box lumber 17

Shrinking and Swelling of Wood . 22

Fxtent 22

How Troubles from Shrinking and Swelling May Be Reduced to

a Minimum in Boxes 23

Checking 25

ix

X CONTENTS

Page

Cupping 25

Casehardening : jrl

Honeycombing ■ 25

Color 25

Odor and taste ^^

AIechanical or Strength Properties of Wood 26

Meaning of strength 26

Tensile strength 26

Compression strength 26

Shearing strength 26

Strength as a beam 28

Stiffness 30

Shock-resisting ability 30

Hardness i 30

Nail-holding power - 30

Care and Seasoning of Lumber in Storage 30

Possible Deterioration in Stored Lumber 31

Checking at ends and on surfaces 31

Twisting and cupping 31

Casehardening, honeycombing, and collapse 31

Blue stain or sap stain 31

Decay or rot 31

Insect attack 32

Proper methods of piling lumber in the yard 32

Foundations and skids 35

Stickers 35

Placing of lumber 36

Size and spacing of piles 36

Kiln-drying box lumber 36

The Use of Veneer in the Construction of Packing Boxes 2>7

Definition ^7

Manufacture of Veneer 37

Method of cutting 2>7

Drying 38

Woods Used for Box Veneers 38

Use of plywood in packing boxes 39

CHAPTER H

Factors Influencing Details of Design 41

Lumber and Veneer 41

Availability and supply 41

Cost 42

Manufacturing Limitations 42

Equipment 42

Cost of operation 42

Styles of boxes 42

Balanced Construction and Factors Affecting Strength 43

Width of stock and joints 43

Corrugated fasteners 45

Physical properties of wood 45

Defects 48

Nailing qualities of wood 51

Fastenings and reinforcements 53

Directions for nailing , 55

CONTENTS xi

Pace

Side nailing 56

Nails for clinching 56

Large nail heads 57

Overdriving nails 58

Screws 59

Strapping and wire bindings 60

Types of metal bindings 60

Reinforcements and Handles 62

Corner irons, hinges, and locks 62

Battens 62

Hand-holds and handles 62

Characteristics of the Various Styles of Boxes 64

Nailed boxes 64

Lock-corner boxes 66

Dovetail boxes 67

Wirebound boxes 67

Panel boxes 70

Factors Determining the Amount of Strength Required 70

Contents 70

Hazards of transportation 71

Factors Determining the Size of a Box 73

Gross weight 73

Desired quantity / 73

Nesting, disassembling, or knocking down contents 73

Minimum displacement 73

Traffic limitations 74

Special Constructions 74

Protection of fragile and delicate contents 74

Vermin 76

Thieving 76

CHAPTER HI

Factors Affecting Strength of Crates 77

Influence of Styles of Crates on Strength 77

Types of corner construction 77

Frame members 78

Skids 79

Bracing long crates 79

Fitting and fastening braces 80

Scabbing 80

Sheating 81

Physical Properties of Wood Affecting Strength 81

Relative thickness of material 81

Defects 81

Nailing and bolting qualities of wood 81

Fastenings and Reinforcements 82

Nails and nailing 82

Bolts and bolting 83

Lag screws 84

Straps 84

Binding rods 84

Internal bracing '. 84 xH CONTENTS

Page

Factors Determining Amount of Strength Required in Crates.. 85

Hazards of Transportation 85

Factors Influencing the Size of Crates oo

CHAPTER IV

Box and Crate Testing

Methods of Testing and Their Significance 87

Drum Test "^

Drop Tests

Drop-cornerwise test

Drop-edgewise test 92

Compression Tests ^2

Compression-on-an-edge test 92

Compression-cornerwise test 96

Compression-on-faces test 96

Supplementary Tests 96

CHAPTER V

Box and Crate Specifications

Purpose 97

Standardization of Packing Boxes 98

General Specifications for Wooden Boxes, Nailed and Lock-corner Construction 99

Material 99

Grouping of Woods 100

Thickness of Lumber ; 100

Thickness of parts 100

Width of parts 101

Surfacing 101

Joining 101

Schedule of Nailing 101

Size of nails 101

Spacing of nails 102

Specific Specifications for Nailed and Lock-Corner Boxes 103

Canned Food Cases 103

General Specifications for 4-One and Similar Boxes 103

General form 104

Grouping of woods 104

Materials 105

Cleats 105

Thin boards 105

Staples 105

Assembling 105

Boxes with wedgelock ends 106

Boxes with detached tops 107

CHAPTER VI Structure and Identification of Woods

Structure of Wood 109

Heartwood and Sapwood 109

Annual Rings 110

Springwood and Summerwood 110

The Structure of Hardwoods 112

CONTENTS xiii

Page

The Structure of Conifers 114

Procedure in Identifying Wood 115

Key for the Identification of Woods Used for Box and Crate

Construction 117

Conifers 122

Description of Box Woods 126

Ring-porous woods 126

Dififuse-porous woods 128

Conifers (non-porous woods ) 132

Grading Rules for Rotary Cut Box Lumber 137

Other species 138

Names and Description of Grades of Lumber Suitable for Packing

Boxes 141

Index 200

TABLES

Page

Factors determining amount of strength required in crates.... 85 Table 1.— Box Woods, Consumption by Box Manufacturers, and

Total Lumber Production 3

Table 2.— Box Lumber Consumption and Total Lumber Production

by States 6

Table 3.— Quantities of Principal Woods Used Annually by Box and

Crate Manufacturers in the Most Important States 7

Table 4.— Approximate Weights of Lumber per Cubic Foot, and per Square Foot of Usual Thicknesses Used in Packing Boxes, Thoroughly Air-Dry (12 to IS per cent moisture),

and Estimated Shipping Weights 12

Table 5. — Per Cent of Shrinkage Across the Grain . 23

Table 6. — Physical and Mechanical Properties of Woods Grown in

the United States 27

Table 7. — Some Physical and Mechanical Properties of Box Woods

on the Basis of White Pine 28

Table 8. — Thicknesses of Box Boards Obtained by Resawing or Dressing 4/4 to 7/4-Inch Lumber 40

Table 9.- — Standard Thicknesses of Hardwoods 41

Table 10. — Holding Power of Nails in Side and End Grain of Various

Species SD

Table 11. — Effect of Size of Heads on Strength of a Nailed Joint.... J7

Table 12. — Resistance to Withdrawal of No. 12 Screws 59

Table 13. — Size of Nails for Crating 83

Table 14. — Size of Bolts for Crating 84

Table IS. — Cement-coated Coolers or Standard Nails and Sinkers or

Countersunk Nails 139

Table 16. — Cement-coated Box Nails 140

Table 17. — Miscellaneous Cement-coated Nails 140

PLATES

Plate L — Defects recognized in the commercial grading of

lumber 163

Plate II. — Cubes of wood magnified about 25 diameters... 164

Plate III. — Styles of wooden boxes, nailed and lock-corner construction 167

Plate IV. — Special styles of boxes 169

Plate V. — Strapped boxes 171

Plate VI. — Types of handles 173

Plate VII. — Different types of corner construction 175

Plate VIII. — Wirebound boxes 177

Plate IX. — -Types of commercial boxes 179

Plate X. — Types of plywood or veneer panel boxes 181

Plate XL — Three-way crate corners 183

Plate XII. — Various arrangements of crate members at three-way

corner 185

Plate XIII. — Crates with special features 187

Plate XIV. — Method of numbering faces of test boxes and crates for convenience in recording data and location of

failures 189

Plate XV. — Different kinds of joints and fasteners 191

XV CONTENTS

Page

Plate XVI.^Hardwoods with pores 193

Plate XVII. — Diffuse-porous hardwoods 194

Plate XV^III. — Softwoods, conifers, or woods without pores or vessels 197 Plate XIX. — Split tangential surfaces of Sitka spruce and Douglas

fir 198

FIGURES

Fig. 1. — Annual lumber consumption by States for the manufacture of

boxes, crates, fruit and vegetable packages 4

Fig. 2. — Relation of moisture content of wood to relative humidity... 17 Fig. 3. — Relation between the volumetric shrinkage and specific gravity

of various American woods 18

Fig. 4. — Cupping of lumber 20

Fig. 5. — Efifect of moisture upon the strength of small clear specimens

of Western hemlock 21

Fig. 6. — End of honeycombed oak plank 23

Fig. 7. — Collapse in 1-inch boards 24

Fig. 8. — Method of measuring twisting of plywood 32

Fig. 9. — Lumber piled sidewise on concrete and metal foundations.... 33 Fig. 10. — A well-kept lumber yard maintained by a large Eastern wood-using factory 34

Fig. 11. — Side view of' lumber piled endwise to the alley with skids

resting directly on the piers 34

Fig. 12. — Efifect of condition and change of condition of lumber on strength of boxes in storage. Boxes for 2 doz. No. 3 cans, nailed with seven cement-coated nails to each nailing edge. . 46 Fig. 13. — -Effect of shrinkage on strapped boxes. Boxes made and strapped at a 30 per cent moisture content ; the boxes were photographed after drying out to 10 per cent moisture

content 47

Fig. 14. — Division of a beam into volumes for describing the location of

knots 48

Fig. 15.— Broken crating of ornamental concrete lighting post 49

Fig. 16. — Efifect of time on the holding power of nails 52

Fig. 17. — Details for nailing standard styles of boxes for domestic

shipment 54

Fig. 18. — Relation of number of nails to amount of rough handling required to cause loss of contents. Nailed boxes for 2 doz.

No. 3 cans 56

Fig. 19. — Iniury to wood fiber resulting from overdriving nails 56

Fig. 20. — Effect of overdriving nails 58

Fig. 21. — Nailed box showing panel style of construction 69

Fig. 22. — Box with corrugated fiber board lining and cells 75

Fig. 23. — Testing boxes in small revolving drum developed at Forest

Products Laboratory 88

Fig. 24. — Standard large drum testing machine developed at Forest

Products Laboratory 89

Fig. 25. — Method of making drop-cornerwise test 90

Fig. 26. — Method of making compression-on-an-edge test 93

Fig. 27. — Method of making compression-cornerwise test 94

Fig. 28. — Method of making compression-on-faces test 95

Fig. 29. — Section of Western yellow pine log Ill

Fig. 30. — Forest regions of the United States 125