L È ß R A R '^ ' September 1959

CURRE 'Ï SERí¿Vi¿gírículture Handbook No. 160

^ ce- i 195'^' ^ i

U, S. DEPARTMENT OF AGRICULTURE

by L. O. Anderson

rb<

FOREST SERVICE

U.S. DEPARTMENT OF AGRICULTURE
CONTENTS

Page

Introduction

o

Types and sizes of nails

Types of nails ^

Common and box nails ^

Cement-coated nails ^

Etched nails ^

Deformed-shank nails ^

Nail points and heads '

Nail sizes ^

How to nail a wood box ^

Nailing of cleats and battens 8

Assembly nailing of boxes ' H

Nailed wood boxes , H

Cleated panel boxes 13

Rules for nailing boxes 14

IÍOW to nail a wood crate 15

Fabrication nailing of open crates 15

Fabrication nailing of crate base 16

Fabrication nailing for sheathed crates 19

Assembly nailing of open crates 19

Fastening sides and ends to base 20

Fastening sides to ends and top 22

Fastening ends to sides 22

Fastening top to ends and sides 22

Assembly nailing of sheathed crates _ _ 23

Fastening sides and ends to base 23

Fastening sides to ends 24

Fastening top to sides and ends 25

Rules for nailing crates 26

Resistance of nails to direct and lateral forces 28

Factors affecting nail resistance to removal forces 28

Surface condition of nails 29

Nail points 30

Nailheads 30

Direction of driving 30

Clinched nails -- 32

Overdriving 32

Prebored lead holes 32

Nails in plywood 32

Placement of nails 33

Diameter of nail 33

Depth of nail penetration 33

Species and density of wood 33

Moisture content of wood 35

How to determine nail resistance 35

Direct-withdrawal resistance 37

Lateral resistance 38

Wood groups 39

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington 25, D.C. - Price 20 cents.
Nailing Better Wood Boxes

and Crates

By L. O. Anderson, Engineer

Forest Products Laboratory,^ Forest Service, U.S. Department of Agriculture

INTRODUCTION

The strength and stability of wood containers depend primarily

on adequate methods of fastening. This has been shown by extensive packaging research conducted at the Forest Products Laboratory

as a part of its program to improve the serviceability and utility of

wood products.

Containers, made of wood can be assembled with a variety of

fastenings, including nails, staples, screws, lag screws, bolts, and

adhesives. Because nails are the most commonly used fasteners in

box and crate construction, their proper use is stressed in this handbook.

Nails are used to fabricate and assemble many styles of boxes and

crates. Two typical box styles and two styles of crates are cited in

this handbook to illustrate the principles of fabrication with nails.

These are the nailed wood box commonly called style 2 in specifications, and the cleatecl plywood box (fig. 1), the sheathed crate (fig.

2), and the open crate (fig. 3). The nailing methods used to make

these containers are adaptable to many other styles, since good nailing principles vary little.

The two basic procedures in box and crate construction are fabrication nailing and assembly nailing. Fabrication nailing means the

nailing of box or crate parts. Examples are the nailing of cleats

to the end'boards of boxes, or sheathing to the frame members of a

sheathed crate panel. Normally in fabrication, the nails are driven

through both members and clinched, unless the total thickness of

the members is too great. Assembly nailing means the assembly of

the sides, top, bottom, and ends of a nailed wood box, or the various

panels of a crate, to form the finished container.

Containers properly nailed with the right kinds and sizes of nails

will be dependably strong and rigid. Containers improperly nailed

may fail even though wood members of adequate size and high qual1 Maintained at Madison, Wis., in cooperation with tlie University of Wisconsin. '

1
HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

BATTEN

END

SHEATHING

SIDE

SHEATHING

BOTTOM

SHEATHING

END

CLEATS

SIDE PANEL THROUGH

EDGE CLEAT

\—FILLER

EDGE CLEAT

INTERMEDIATE

CLEAT

THROUGH

CLEAT

B

M-114177

FIGURE 1.—Typical wood boxes: A, Style 2 nailed wood box; ß, cleated panel box.

ity are used. Adequate nailing means not the use of a large number

of nails but rather the use of the correct sizes, numbers, and types!

of nails at the right places. The purpose of this publication is to

describe the most important aspects of good nailing for wood boxes

and crates.
NAILING BETTER WOOD BOXES AND CRATES

^SIDE FRAME MEMBER

/STRUT '^

DIAGONAL

JOISTUPPER

FRAME MEMBER

JOIST SPACER

3

^DIAGOñ/AL EDGE STRUT

SHEATHING

SKID

f FIGURE 2.—Typical lumber-sheathed crate.

TYPES AND SIZES OF NAILS

Types of Nails

Nails are available in such great variety that they can be used for

almost any purpose requiring fasteners. These nails are made in

many sizes and shapes, from steel, aluminum, copper, and other

metals. Not all types, however, are satisfactory for boxes and crates.

Some of the more common types used in containers are shown in

figure 4.

Common and Box Nails

Common nails and smooth box nails are most often used in fabris cation nailing where clinching is required. A nail that is to be

s clinched need not be coated nor given any other treatment to increase

tiits withdrawal resistance. Common and box nails have the same

¡¡length, but the box nail is smaller in diameter (table 1).
HANDBOOK 160, tJ.S. DEPARTMENT OF AGRICULTURE

-DIAGONAL

TOP STRUT

LOWER FRAME

MEMBER

SKID

-DIAGONAL

-RUBBING STRIP

FIGURE 3.—Typical open crate.

Clout nails are commonly used to fasten plywood or other slieej

materials to cleats of boxes or to thinner frame members of cratei

These nails, available in lengths from 3^ to IV2 inches, have long,

tapered, duckbill points that clinch easily (fig. 4), and larger heads

than other container nails of comparable length.

Cement-Coated Nails

Cement-coated nails are steel nails with a resin or similar coatirl

that increases their withdrawal resistance. These nails are the moi

common type used in the assembly of boxes and crates. Cemen

coated nails can be obtained in a variety of sizes and diameters ; tl

most common types are sinkers, coolers, and box nails (fig.

Corker nails are also available with cement coating, although n(

often used for box and crate construction.

Etched Nails

Etched nails are bright steel nails (fig. 4) that have been treati

in a chemical solution developed at the Forest Products Laboratq

to roughen the surface and thereby increase withdrawal resistanc

The surface does not deteriorate as much as the coating on cemen

coated nails. Any steel nail may be treated with this solution.

Clean, bright nails can be effectively etched. Eemove any lubij

cant on the nails before treatment.
NAILING BETTER WOOD BOXES AND CRATES

tl

I

B H

' O M-l 13736

FIGURE 4.—Nail types: A, Common; B, clout; C, sinker (cement-coated); D,

cooler (cement-coated); E, box (cement-coated); F, etched; G, spirally grooved;

H, annular-grooved.

Etching is clone as follows :

(1) Prepare a 10 percent solution (by weight) of commercial

monoammonium phosphate in water. Do not use a metal container

to prepare or store the solution. Keep the solution at room temperature, approximately 70° F. Five gallons of solution are sufficient to etch 100 pounds of nails.

(2) Immerse the nails in the solution for about 7 hours and stir

occasionally to change the position of the nails for more uniform

treatment.

(3) At the end of the etching period, remove the nails from the

solution, rinse them thoroughly in water, and dry them to prevent

rusting.

Other roughened-shank nails with somewhat increased withdrawal

resistance include sandblasted, parkerized, and galvanized nails.

Galvanized, stainless steel, aluminum, copper, and brass nails are

used in special containers intended for service under severe shipping

and storage conditions where rust must be avoided.

Deformed-Shank Nails

Deformed-shank nails retain a great percentage of their withdrawal resistance even after the wood has undergone many changes

in moisture content. The two most common varieties of deformedshank nails are the spirally grooved nail, which has a series of

spirals around its shank, and the annular-grooved nail, which has
6 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

TABLE 1.—Dimensions and nwnher per pound of standard sizes and

kinds of nails commonly used for boxes and crates

LENGTH IN INCITES

Size of nail ^

Bright Cement-coated

Common Box Corkers Sinkers Coolers Box

2d 1

1%

l'A

1%

2

0 ],<;

2%

3

3 M

S H

4

VA

VA

l'A

2

2%

2A

2%

3

3/4

3K2

4

1

VA

1%

VA

VA

2A

2%

'2l{

3d

2%

2%

3%

\%

1%\%

VA

2/8

2%

2%

2%

3/

3;4

3%

VA

4d VA

5d VA

6d VA

7d

8d - --

2%

2%

9d ___ 2%

lOd

12d

2%

16d

20d

GAGE 2

2d_

3d.

4d_

5d.

6d.

7d_

8d.

9d.

lOd

12d

16d

20d

15

14

12^2

12>v

11/2

11/

10/

10/

9

9

8

6

15/

14/

14

14

12/

12H

11/

11/

10/

10/

10

9

12]

11

11

10

15/

14

13/

13

12/

11/

11/

11

10

9

7

16

15/

14

13/

13

12/

11/

11

16

15/

15

13/

13/

12/

12/

11/

APPROXIMATE NUMBER OF NAILS PER POUND

2d.

3d.

4d_,

5d_.

6d.

7d.

8d_.

9d..

lOd

12d

16d

20d

830

528

316

271

168

150

106

96

69

63

49

31

1,010

635

473

406

236

210

145

132

94

88

71

52

23i^

129

114

84

36

850

495

364

275

212

142

130

104

77

61

37

1,094

848

488

364

275

212

142

104

988

710

522

310

283

191

172

118

1 Nails are available in sizes up to sixtypenny. Bolts are usually preferred in

boxes and crates, however, where nails larger than twentypenny would be

required.

2 Conformed to the American Steel and Wire Company steel wire gage.
NAILING BETTER WOOD BOXES AND CRATES 7

small grooves around its perimeter (fig. 4). In general, annulargrooved nails sustain larger static-withdrawal loads and spirally

grooved nails sustain greater impact-withdrawal loads than do other

nails.

Nail Points and Heads

Diamond-pointed nails are perhaps most commonly used in container construction. The clout nail has a duckbill point that is

easily clinched because of its taper. Some special nails have a needle

point or a chisel point. A sharply pointed nail will cause splits in

denser woods. To minimize these splits, slightly blunt the i)oint of

the nail before it is used. When only a few nails are needed, blunt

them with a hammer. Blunting on an emery wheel is more practical when a large number are needed.

Railheads vary somewhat in diameter and thickness (fig. 5). The

flat head is used for the common nail, the cement-coated cooler, and

other similar nails./ The countersunk head, used for the sinker nail,

provides additional strength and does not break off easily. The

cement-coated box nail has a broad, flat head. Do not use this type

of nail in dense hardwood, or where an uneven blow may shear off

the head.

D

H M-l 13737

FIGURE 5.—Nail points and heads: A, Diamond; B, needle; C duckbill; Z), chisel;

E, blunted; F, flat; G, countersunk; E, broad flat.

501506"—59 2
8 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

Nail Sizes

The size of most nails, particularly those used for containers, is

based on their length; the diameter or gage varies with length and

nail type. The usual designation for these nail sizes is expressed

by the "penny^' system, abbreviated as "d." Thus, a sixpenny nail

is expressed as 6d, and an eightpenny as 8d. The penny system

originated in England, where it is said to have been based on the

weight of a thousand nails; that is, 1,000 tenpenny nails weighed

10 pounds and 1,000 eightpenny nails 8 pounds.

Bright common nails and box nails are of the same length, but

box nails are smaller in diameter for a given penny size (table 1).

Among cement-coated nails, sinker nails are available in the greatest

range of sizes. In sizes less than tenpenny, the four types of

cement-coated nails are of the same length for each penny size.

These nails are i/g inch shorter than bright common nails and box

nails of equivalent penny size (table 1). Bright box nails are

larger in diameter than cement-coated box nails of equivalent

penny size.

HOW TO NAIL A WOOD BOX

Generally speaking, box manufacturers use automatic nailing

machines as much as possible. These machines drive and clinch a

number of nails at one time and can be readily adjusted for the

fabrication of box parts of various sizes. They are also used to

fasten the sides and bottom of the box to the ends; the top is often

nailed on by hand after the contents are packed. The fabricated

box parts that form complete units are called "box shook" and are

shipped to the user in knocked-down form. The nailing principles

discussed here for the fabrication and assembly of two common styles

of boxes may be adapted to almost any similar container.

Nailing of Cleats and Battens

Ends of nailed wood boxes and panels of cleated panel boxes are

usually fabricated with nails that are driven through both the cleat,

or batten, and the sheathing and then clinched (fig. 6). Nails

should be long enough to allow for proper clinching. This extra

length should be at least i/g inch for fourpenny and smaller nails,

1^ inch for fivepenny, sixpenny, and sevenpenny nails, and % inch

for eightpenny nails. Longer nails require a longer clinch because

of their greater diameter. Clout nails, however, should be clinched

at least 14 ii^^h because of their thin, tapered, duckbill point.

These recommendations are based on the strength advantage of

an adequate clinch. Too long a clinch is undesirable because of the

difficulty of burying the nail point and the end of the shank into
NAILS CLINCHED

ON SHEATHING SIDEs

NAILING BETTER WOOD BOXES AND CRATES

-f MINIMUM

9

Í^'MINIMUM

CLEATS

NAILS CLINCHED

ON CLEAT SIDE, MINIMUM

B

MINIMUM

M-114116

FIGURE 6.—Nailing patterns and spacings for box ends of A, a nailed wood box,

and Bj a cleated panel box.

the wood. Clinching across rather than parallel to the grain of the

wood is recommended because it gives 20 percent greater withdrawal resistance.
10 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

Nails are usually clinched against the sheathing. However, in;

cleated panel boxes made with plywood or some other sheathing^

material that is too thin, it is best to clinch against the cleats for

greater strength. Clinching makes it especially, important to select

nails witli heads that will not shear off when they are driven. Such

nails include sinkers, coolers, corkers, and common nails. Common^

nails and sinker-type nails are often used and are a good choice

because they are available in many lengths. Sinker nails have^

strong countersunk heads that prevent their breaking off when used;

in hardwoods. i¿

In nailing plywood, fiberboard, or other sheathing material to thei

cleats, use nails with heads large enough in diameter to preventj

their being pulled through the sheathing. These nailheads should|

also be thick enough so that they will not shear off. In box con-j

struction, use a nail with a head not less than %2 i^^^h in diameter,^

especially in fiberboard, paper-overlaid veneers, and the thinner plywoods. Various types of nails, in the sizes and shank gages commonly used to make cleated panel boxes, are shown in table 2.

TABLE 2.—Types of nails often used to fasten sheathing to cleats of^

cleated panel boxes

Nail type Size Length Gage Head

diameter

Box (smooth) _

Clout

Penny

Sinkers.

CoolersCommon.

Inches

1/4

1/2

1/4

%

%

1

1/8

1/4

1%

1/

1/8

1/8

1/8

1/

1/4

14

14

15

14

14

14

13

13

13

13/2

14

13/

12/

12/

Inches

The nails used to fasten the sheathing of nailed wood boxes anc

cleated panel boxes are driven in a two-row staggered patteri

(fig. 6). For nailed wood boxes, the recommended spacing of naill

in each row is as follows:

Average spacing

Nail size (penny) : (inches)

6 or smaller 2

7 214

8 2%

9 2%

Nail size (penny):

10

12

16

Average spacing^

(inches)

3

SM,

___ 4 ]
NAILING BETTER WOOD BOXES AND CRATES 11

Space rows of nails not less than % inch apart ; % inch or more

is better if the cleat is wide enough, particularly with the larger

nails, in order to avoid cleat splitting. In wide cleats, each roAv

should be about % inch from the nearest edge. Space nails evenly

along the length of the cleat. The first nail at either end of the

cleats should not be closer than % inch nor farther than 11/2 inches

from the cleat end (fig. 6). Nail each board in an end panel to

each vertical cleat with at least two nails.

Nail interior battens for the sides, reinforcino; cleats, diai>:onals,

and similar members of wood boxes as described for end cleats.

The cleats in cleated panel boxes should be nailed as described

for the ends of the nailed wood box, but space the nails in each row

not more than 6 inches apart.

Assembly Nailing of Boxes

Assembly nailing of a box requires the use of coated nails or nails

with roughened or deformed shanks to increase withdrawal resistance. The nails should have strong heads of sufficient size to pre-

.. vent them from pulling through the wood or breaking oil'. The

types used for box part fabrication—such as sinkers, coolers, and

^ corkers—are satisfactory.

Nailed Wood Boxes

\ Although no definite assembly procedure need be followed, the

I logical first step is to nail the sides of a box to the ends. Nail the

'¡side sheathing of nailed wood boxes to the ends (fig. 7). The nails

!* are placed in a staggered pattern by alternately nailing into the end

h cleat and the end sheathing.

5' A good rule to follow in selecting nails of proper size is that the

\iiail be long enough to penetrate at least 2 to 21/2 times the thick-

;ness of the sheathing or the fastening members. Table 3, which

"lists nail sizes for box assembly purposes, gives data of value in

selecting the proper nails for low- and high-density woods according to the grouping by species shown on page 39.

Place the first nails in the top and bottom boards of the side

^sheathing at about one-half the spacing distance (designated on

t^^page 10) from the edges (fig. 7). This distance may vary a little

öftecause of knots, checks, or the location of fabrication nails. Drive

at least two nails at each end of each board of the sides.

,j. For nailed wood boxes, space the nails as shoAvn on page 10. If

*'.the sheathing frequently splits, nails one penny smaller can be used

jand spaced one-fourth inch closer than is specified on page 10 for

^inails of the size actually used.
12 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

,6"TO 8"SPACING

I(SIDES-fAND THICKER) NAIL TO CLEATS

AND ENDS

USE 2 NAILS FOR \

CLEATS 2-^' AND

WIDER

STYLE A

B STYLE B

FIGURE 7.—Assembly nailing patterns for A, nailed wood box, and ß, cleatq

panel boxes.

The bottom and top sheathing boards are nailed to the end sheatl

ing and end cleats in the same general manner described for th

sides.

Top and bottom boards are sometimes nailed to the side sheathii

when the thickness of the side sheathing is at least three-fourths^

an inch. Sevenpenny nails are used for side sheathing less than

inch thick and eightpenny nails for thicker side sheathing. Spa

nails about 6 to 8 inches apart (fig. 7).
NAILING BETTER WOOD BOXES AND CRATES 13

TABLE 3.—Nail sizes recommended for assembly of nailed wood boxes

made of tooods grouped for density ^

Thickness of sheathing (inches)

Size of nails

Group I

woods

Group II

woods

Group III

woods

Group IV

woods

%

/2

Ys

3/4

%

1 to 1%

Penny

6

7

8

9

10

12

Penny

5

6

7

8

9

10

Penny Penny

1 Group I, soft woods; II, hard coniferous woods; III, medium density hardwoods; IV, heavy hardwoods.

elected Panel Boxes

Assembly nails used to attach the ends of cleated panel boxes

cannot be placed in a staggered pattern ; all must be driven into the

edge cleats (fig. 7). This type of nailing may cause the cleat to

split if the nails are too large or the nail spacing is too close. The

choice of nail length should be based on the combined thickness of

the panel material and the cleat. The penetration of the nail into

the edge of the cleat should be about twice this combined thickness.

. . . T

Table 4 gives nail sizes and spacings recommended for nailing side,

top, and bottom panels to the ends, and the top and bottom panels

to the sides. However, nails should not be so long that they penetrate the opposite edge of the cleat.

Space assembly nails evenly, and use at least one nail in the end

of each cleat that is less than 2% inches wide; in wider cleats, use

2 nails (fig. 7).

TABLE 4.,—Nail size and spacing for assembly of cleated panel boxes

Combined thickness of panel and cleat (inches)

%-.

%-.

1__

1/8.

1/4

1%

Size of nails

Group I

and II

woods

Penny

8

9

9

10

10

12

Group

III and

IV woods

Penny

7

8

8

9

9

10

Spacing

of nails

(all wood

groups)

Inches

5

5

4/2

4/2

4

4
14 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

Most boxes are reinforced with wire or flat metal tension straps.

These straps are pkiced around the perimeter of a nailed wood box

and stapled in place. On cleated panel boxes the straps are placed

on the cleat around the top, bottom, and ends. Under most conditions, strapping has some vahie for nailed wood and cleated panel

boxes when properly placed and stapled. However, it presents a

snaefírinfí: hazard when il becomes loose.

Rules for Nailing Boxes

1. Bright nails may be used to fasten sheathing to cleats if the

nails are clinched. Use coated, etched, or other types of roughenedor deformed-shank nails, however, if clinching is not done. For

lumber sheathing, use common, sinker, cooler, corker, or similar

types of nails. For plywood sheathing, use clout nails.

2. Clinch nails across the grain of the wood. Allow a length af

clinch of not less than % inch for fourpenny and smaller nails,

1/4 inch for fivepenny, sixpenny, and sevenpenny nails and clout

nails, and % inch for eightpenny nails. Longer nails may require

a y2-inch clinch.

3. Fasten cleats or battens of box parts to sheathing with two

rows of nails whenever possible. Likewise, place assembly nails in

a two-row or staggered pattern when practical.

4. In the fabrication of nailed wood box parts, nail the ends of

each end-sheathing board to each vertical cleat with at least two nails.

5. Drive nails so that neither the head nor the point projects

above the surface.

6. When nailing sides, top, and bottom to the ends of nailed wood

boxes, put at least two nails in each end of each sheathing board.

7. For assembly of sides, top, and bottom to the ends, use nails

long enough to penetrate into the ends 2 to 21/^ times the thickness

of the sheathing.

8. If the desired nail is not available or wood splitting cannot be

avoided by slightly blunting the nail point, use the next smaller nail

and decrease nail spacing slightly.

9. When two rows of nails are required in the assembly of boxes,

drive the nails alternately into the cleat and the sheathing.

10. If the sides are at least % inch thick, fasten the top and

bottom sheathing to the sides with nails spaced 6 to 8 inches apart.

11. T\nien nailing thin plywood, fiberboard, and paper-overlaid

veneer to the cleats, use nails with heads at least %o inch in diameter ; this will prevent them from pulling through the sheathing.
NAILING BETTER WOOD BOXES AND CRATES 15

HOW TO NAIL A WOOD CRATE

Proper fabrication nailing of panels of both open and sheathed

crates develops the full strength of the crate and its members. In

open crates especially, fabrication nailing of panels is critically

important. In sheathed crates, the fabrication nailing joins adjacent members by means of sheathing that is securely nailed to all

frame members.

The construction and appearance of a crate are quite different

from that of a wood box, but the principles of nailing are similar.

Fabrication of the parts consists of nailing various framing pieces

together, with or without sheathing, to form panels. Assembly consists of fastening these panels together to form the container. The

sizes of nails recommended in this handbook for assembly of crates

are those generally used for group I and II woods (see page 19).

When woods of groups III and IV are used, use nails one penny

smaller for assembly nailing.

Fabrication Nailing of Open Crates

One of the simplest crates to build is the open crate. The key to

good fabrication nailing of its panels is effective nail clinching.

Because the sides, ends, and tops of open crates are much alike, the

same nailing methods are employed for all. The parts of each panel

are laid on one another and nailed together at the proper places;

the nails are clinched on the inner face (fig. 8).

The nailing patterns and the number and placement of the nails

should be such that the full strength of the members is approached.

However, don't use too many nails, for they may split the wood.

The nailing patterns recommended for woods of groups I and II

are shown in figure 9 for crate members crossing at right angles.

Use at least two nails for each joint. For woods of groups III and

IV, the number of nails per joint may be decreased by one if the

wood splits when the designated number of nails is used. For members crossing at angles other than 90 degrees, patterns similar to

those in figure 9 should be used. A detailed nailing pattern for the

base is shown in figure 10.

Clinch all nails used in the fabrication of open crates, unless the

member containing the nail point is more than 2 inches thick or the

total thickness of all members exceeds 3 inches. A i^-inch minimum

clinch is recommended for sevenpenny and smaller nails; a 3/g-mch

clinch for eightpenny through twelvepenny nails; and a l/g-inch

clinch for larger nails.

501506"—59 3
16 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

CLINCH NAILS ON

/BACK FACE

LOWER FRAME

MEMBER DIAGONAU AREA FOR ASSEMBLY

NAILING

UPPER FRAME

MEMBER

CLINCH NAILS ON

BACK OF STRUT

NAIL TO EDGE STRUTS

AREA FOR NAILING

END TO BASE

B

M-l 11518

FIGURE 8.—Typical construction for open crates: A, Fabrication of sides or top;

B, fabrication of ends.

Fabrication Nailing of Crate Base

The framing of bases for sheathed and open crates is similar.

The cross members, including the end headers and the larger loadbearing floorboards, are usually bolted to the skids (fig. 10). The

diagonals, cross members, and lumber and plywood flooring are

nailed to the skids. The nailing patterns shown in figure 9 are

used to fasten members, except plywood flooring, to the skids. Ply-
NAILING BETTER WOOD BOXES AND CRATES

fEDGE MEMBER

STRUTS AND

DIAGONALS

17

rOROSSING MEMBERS

' '•^

ë £ H

OR GREATER

Nh

^

FiGUBE 9.^-Typical nailing patterns for open crates: A, Nailing for assembly of

panels to each other ; 5, nailing for fabrication of panels, as used to nail floorboards to skids and lumber sheathing to frame members.

wood flooring is nailed in a two-row staggered pattern, with the

nails in each row spaced about 6 inches apart.

The nails should be long enough to penetrate the skid for a distance 2 to 21/2 times the thickness of the member holding the head

without projecting through, but not less than IV2 inches. Thus, to
18 HANDBOOK 16 0, U.S. DEPARTMENT OF AGRICULTURE

BOLT HEAVY MEMBERS

TO SKIDS

NAIL r MEMBERS

TO SKIDS WITH

8à OR 9^ NAILS

RUBBING STRIP

SKID

BOLT TO SKIDSFILLER PIECE

(SPACE NAILS

6"'8" APART)

PLYWOOD TO SKIDS

2 ROWS OF NAILS

I' FLOORING

2" FLOORING

FIGURE 10.—Typical constructions for crate bases: A^ Base for open crates; B,

for sheathed crate.

nail a %-inch-thick board to a large skid requires a nail about 2^4

to 2% inches long ; for example, an eightpenny or ninepenny cementcoated sinker nail, or an etched eightpenny common nail. Under

most conditions, these nails have higher withdrawal resistance than

plain nails. If, however, clinching is required because the total

thickness of all parts is no greater than 3 inches, plain nails are

suitable.
NAILING BETTER WOOD BOXES AND CRATES 19

Fabrication Nailing for Sheathed Crates

The sides, ends, and tops of sheathed crates are fabricated by

placing the precut frame members in their proper positions and

tastenmg them together with corrugated fasteners or staples. Wlien

a considerable number of crates of the same size and construction

are to be made, jigs are often used to hold the members in position

while the sheathing is applied. In lumber-sheathed crates, waterproof paper can be installed between the frame members and the

sheathing of side and end panels to seal the joints between sheathing

boards. Tops are waterproofed by various means; one effective way

IS to place waterproof paper between two layers of the lumber

sheathing. Plywood-sheathed crates do not require this type of

waterproofing, as all plywood joints are made over a frame member

and are securely nailed (fig. 11).

Nails are driven through both the sheathing and the frame members. If the total thickness of the wood is less than 3 inches, the

nails are clinched. The length of the clinch depends on the size

of the nails required for the joint, and the general rule outlined for

open crates should be followed. Coated, etched, or deformed-shank

nails recommended for fastening plywood % inch or less in thick-

^ness to 2-inch frame members need not be chnched, but should penetrate to a depth of at least 11/2 inches into the frame member.

Figure 11 shows recommended spacing and placement of nails

used to fabricate side, end, and top panels of sheathed crates. Drive

the nails through the thinner into the thicker member; if these

members are of equal thickness, convenience is the controlling factor.

Crate tops often have joists or similar supporting members that

are usually installed on edge either before or during crate assembly.

Nails are driven through the top sheathing and frame members

into the joists. Use two nails where each joist crosses diagonal or

longitudinal frame members. Twelvepenny nails are suitable when

both sheathing and frame members are nominally 1 inch thick, and

tenpenny nails are used with %- or i^-inch plywood sheathing.

When nailing through a strut of the top into a joist, space the nails

about 8 to 10 inches apart.

Assembly Nailing of Open Crates

It is relatively simple to assemble open crates, because there is no

great amount of "blind" nailing involved. Most of the nailing is

"direct" : that is, the pieces holding the nailheads and those holding

the points are in plain view (fig. 12). Most nailing, therefore, does

not require accurate marking for alinement of the assembly nails.

However, it is good practice to indicate by some method the number

and placement of the nails.
20 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

MINIMUM OF 3 NAILS

PER SHEATHING BOARDSTRUT

-J NAILS (MIN) PER

BOARD

DIAGONAL

^CLINCH NAILS ON INSIDE

FACE OF FRAME MEMBERS

SHEATHING

-CLINCH ON FRAME

MEMBER SIDE

//T ^ '

/ '

1 i!-

! ÏI' \ \ \ \ ^

\\\\A W

\\ \ \ VI

1 iLVLL'-'liJi-LiJ iViJ-lj-V---J

^.UPPER FRAME

MEMBER

USE 2 ROWS OF

NAILS FOR 4" WIDE

MEMBERS AND 3

ROWS FOR 6"AND

WIDER MEMBERS

PLYWOOD JOINT

-STRUT

B

FIGURE 11.—Typical construction for sides, ends, and tops of sheathed crates:

á, Lumber-sheathed crates; B, plywood-sheathed crates.

Fastening Sides and Ends to Base

Fasten the struts of the side panels to the base by nailing them

to the skids or other large base members. Nail diagonals that are

in the same plane as the struts and extend below the lower frame

member to the skid also. The number of nails used depends on the

gross weight of the crate and its contents. In properly designed

crates, the greater the weight of the article, the larger the struts,

diagonals, and skids; hence greater nailing area is automatically

provided.
NAILING BETTER WOOD BOXES AND CRATES

TOP TO SiDEK o/^^ ^^ ^^^

21

TOP TO END

END TO BASE

END TO SIDE

SIDE TO BASE

(USE LAG SCREWS FOR

HEAVY CRATES)

SIDE TO END

FIGURE 12.—Typical assembly nailing for open crates.

Nail each strut and diagonal of the sides to 2-inch skids with at

least three nails for 1 by 4's and four nails for 1 by 6's. Wlien

skids are 3 inches deep or more, use at least four nails for 1 by 4's

and five nails for 1 by 6 diagonals and struts. Heavy loads or small

crates, however, may require a greater number of nails to fasten the

sides to the base. The total number of nails required is shown in

table 6 by nail sizes and types for various gross loads.

Stagger the nails in patterns similar to those shown in figure 9,

and the struts and diagonals nailed to the skids or sills as shown

in figure 12. In table 5, eightpenny, ninepenny, and tenpenny nails

are listed, any of which may be used to fasten nominal 1-inch

members to the base.

For heavily loaded crates, the number of nails required may be

so great that their use would not be practical without additional

struts and diagonals. Under these conditions, the use of lag screws

is recommended. For example, the allowable lateral resistance of

a lag screw % inch in diameter and penetrating IV2 to 2 inches into

the skid is at least 4 times that of an eightpenny or ninepenny

sinker nail. Thus, two lag screws will do the work of eight nails

and require a small total fastening area.

The ends are fastened to the base by nailing the lower frame

member of the end to the end header. Eightpenny or ninepenny

nails spaced about 8 inches apart are used in a staggered pattern

(fig. 12).
22 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

TABLE 5.—Tot(d ininimwn nuniber of nails required to fasten sides to

hase of open crates ^

Gross load—

weight of

crate and

Sinker or cooler

nails

Corker nails Common nails

contents

(pounds) 8d and 9d lOd 8d and 9d lOd 8d and 9d lOd

1,000 20

38

58

76

96

114

134

152

18

36

54

72

90

108

126

144

18

34

52

68

86

102

120

136

16

30

46

60

76

90

106

120

16

30

46

60

76

90

106

120

14

2,000. _ _ 26

3,000 40

4,000. 52

5,000 _ 66

6,000 78

7,000 92

8,000 104

^ Use one-half on each side of crate and divide evenly between struts and

diagonals according to their respective widths.

Fastening Sides to Ends and Top

In most open crate designs, the frame members are arranged so

that the sides can be fastened to both the end and the top panels.

The edge struts of the sides overlap the edge struts of the ends

(fig. 12), and the nails should be placed about 8 to 10 inches apart.

For nominal 1-inch members, eightpenny or ninepenny nails are

driven through the edge struts of the sides.

The upper ends of the struts and the diagonals are fastened to

the edge longitudinal members of the top with eightpenny or ninepenny nails (fig. 12). The nailing patterns for open crates shown

in figure 9 may be used. Nails placed too near the end often cause

boards to split, especially those of the denser woods. Reduce splitting by slightly blunting the ends of the nails. If splitting persists,

either predrill nail holes or select nails that are onepenny smaller.

If smaller nails are used, more nails will probably be required.

Fastening Ends to Sides

In the design and construction of most open crates, the cross

members and the diagonals of the ends extend beyond the edge

struts. Nail these to the edge struts of the side panels (fig. 12).

Two eightpenny or ninepenny nails are used for 1- by 4-inch members, three nails for 1- by 6-inch members, and four nails for 1- by

8-inch members.

Fastening Top to Ends and Sides

The construction of top panels for open crates differs according

to the position of the longitudinal members and the cross members.

These variations may change the method of nailing the tops to the
NAILING BETTER WOOD BOXES AND CRATES 23

ends. In most cases, the longitudinal edge members of the top are

nailed to the upper frame members of the sides (fig. 12). For group

1 and most group II woods, use eightpenny or ninepenny nails

spaced 8 to 10 inches apart.

-In panels where the cross members are over the longitudinals,

nail the edge struts of the top to the upper frame members of the

ends. Use eightpenny or ninepenny nails spaced 8 to 10 inches

apart (fig. 12). In top panels where the top longitudinal members

pass over the cross struts and diagonals, the upper frame member

of the end is fastened to the edge strut of the top with nails spaced

8 to 10 inches apart.

These nailing principles can be applied to many styles of crates

other than the basic ones described here.

Assembly Nailing of Sheathed Crates

The assembly nailing procedures recommended for sheathed crates,

while similar to those for open crates in some respects, also differ

considerably. The reason is that much assembly nailing consists

of driving the nails through the sheathing directly into a structural

member. There is also more nailing surface. This allows more

uniform nail spacing and eliminates the concentrations of nails.

The latter, common in open crates, is often the primary cause of

splits when the loaded crates are stressed by rough handling during

transit.

Sheathed crates can be designed to carry greater loads than open

crates. The greater fastening area available allows the use of more

nails, which contributes greater resistance to lateral load stresses.

In small open crates, for example, only two or three struts may be

available to receive nails, but a sheathed crate can be nailed along

its entire length. As in all assembly procedures, coated, etched, or

deformed-shank nails provide superior withdrawal resistance.

Fastening Sides and Ends to Base

In sheathed crates, the side panels are nailed to the skids and the

end panels are nailed to the end headers of the base. When 2- by

4-inch skids or headers are used flat, stagger the nails slightly

(fig. 9). If skids or sills 3 or 4 inches deep are used, place the

nails in two rows in a staggered pattern; for skids or sills deeper

than 4 inches, three rows of nails are used (fig. 13).

Generally, eightpenny and ninepenny nails are used for nominal

1-inch lumber sheathing and 1/2-inch and thicker plywood, and

sevenpenny nails for plywood sheathing less than 1/2 inch thick.

The minimum number of nails for the side-to-base nailing is governed by the gross weight of the crate and its contents. Table 6

501506°—59 4
24 HANDBOOK 16 0/U.S. DEPARTMENT OF AGRICULTURE

TOP TO ENDTOP TO SIDE

LUMBER

SHEATHING

SIDE TO TOP

-PLYWOOD

SHEATHING

SIDE TO BASE

(USE LAG SCREWS FOR

HEAVY CRATES)

END TO BASE

END TO SIDE-

^SIDE TO END

FIGURE 13.—Typical assembly nailing for sheathed crates.

lists, by types of nails and wood groups, the number of nails required for each 1,000 pounds of gross load.

Good practice calls for at least two nails in each lumber sheathing

board. In addition, space nails used to fasten sides and ends to the

base no farther apart than 3 inches when in single rows, 6 inches in

double rows, and 9 inches when three rows are used. Nails spaced

too closely will split the sheathing. If nail requirements result in

spacing of less than II/2 inches, nails should be replaced with lag

screws installed as described for the side-to-base assembly of open

crates.

Fastening Sides to Ends

The side panels are fastened to the end panels with nails driven

through the sheathing of the sides into the edge struts of the ends.

The nails are spaced about 6 to 8 inches apart (fig. 13). Nail sizes

are the same as those recommended for side-to-base assembly. The

end panel is fastened to the side panel with nails through the

sheathing and edge strut of the end into the edge strut of the side.

The edge strut of the side is usually a 2-inch or thicker member.
NAILING BETTER WOOD BOXES AND CRATES 25

TABLE 6.—Number of nails ^ needed to fasten sides of sheathed crates

to hose for each ipOO founds of gross load^ hy wood group

Nail type 2 and size Group II

woods

Group III

woods

Group IV

woods

Sinker or cooler:

7d 23

19

18

17

15

19

15

13

26

21

19

19

16

21

17

14

19

8 or 9d_. _ _ ._ ___ 16

lOd 14

Corker:

8 or 9d ._ _-_ _ __ _ 14

lOd 12

Common:

7d _ ___ _ 16

8 or 9d„ - _ _ 13

lOd - - 10

Vs

1 Use one-half of total required for each side.

2 Should have coated, etched, or deformed shanks.

For lumber sheathing, this requires twentypenny nails and pre

drilled nail holes to prevent splitting of the members. Holes

inch in diameter should be satisfactory. When %-inch plywood

sheathing is used, a twelvepenny nail is satisfactory. Space nails

about 12 inches apart (fig. 13).

Fastening the sides and ends to each other in this manner results

in a rigid crate corner, because no matter how the corner is stressed

during handling and shipping, at least one set of nails will be in

lateral resistance.

Fastening Top to Sides and Ends

The construction of the top panels of sheathed crates varies a

great deal. Narrow crates do not require top joists to support top

loads, since the sheathing alone has sufficient strength. In wider

crates, however, joists are used to carry these loads. Because of

these and other variations, such as joist support systems, the nailing

procedure for fastening tops to sides and ends may be quite different. Whenever possible, however, nailing should be in two directions : from top to side and from side to top.

The nails for fastening the sides and ends to the top are driven

through the sheathing into an edge or other frame member of the

top. Use eightpenny or ninepenny nails for lumber sheathing and

sevenpenny nails for plywood sheathing less than 1/2 "^ch thick.

Space nails about 6 inches apart (fig. 13).

The top is fastened to the sides and ends with nails driven through

the sheathing and edge members of the top, and into the upper

frame members or joist spacers of the sides and ends. For top

frame members 1 inch thick, twelvepenny nails are needed to get
26 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

at least l^o inches of penetration into the side or end members.

For %- or i/2'ii^ch plywood sheathing, tenpenny nails are adequate.

Space nails about 8 inches apart.

These assembly nailing methods may not be strictly applicable to

all styles of sheathed crates, but the principles on which they are

based apply fairly generally. In addition to assembly with nails

and lag screws, many crates are strapped with a metal corner-reinforcing strap. This affords some additional measure of safety under

the severe handling that may be encountered in export shipping.

However, for domestic shipment, and for crates that have a large

amount of two-way nailing, strapping is often unnecessary. Tension straps are sometimes used to fasten tops to sides and ends of

special crates; for example, to permit removal of the top simply by

cutting the straps.

Rules for Nailing Crates

1. Unless nails are clinched, use cement-coated, etched, or deformed-shank nails to gain increased withdrawal resistance. Nails

used for assembling crates should have a diameter at least equal to

that of the sinker nail (table 1).

2. In fabrication of panels for large sheathed crates, fasten adjacent frame members to each other with corrugated fasteners or

staples before the sheathing is applied, unless jigs are used. This

aids in the alinement of the various frame members.

3. Whenever possible, drive nails through the thinner into the

thicker frame member. This is recommended especially when plywood is fastened to nominal 1- or 2-inch members.

4. A^Hien nailing two pieces of lumber together flatwise, as in

panel fabrication, clinch the nails if the combined thickness is 3

inches or less. Use a 1/4-inch clinch for nails up to sevenpenny in

size, a %-inch clinch for eightpenny through twelvepenny nails, and

a y2-inch clinch for larger nails. Plywood % inch or less in thickness may be nailed to nominal 2-inch members without clinching if

the nails penetrate II/2 inches into the members.

5. When the combined thickness of two pieces of lumber nailed

together flatwise is more than 3 inches, or when the flat face of one

member is nailed to the edge of another, nails are not clinched.

Tenpenny and smaller nails should penetrate into the piece holding

the nail point for a distance equal to about 2 to 21/2 times the thickness of the piece holding the nailhead. Twelvepenny and larger

nails should penetrate at least 11/2 inches into the piece holding the

point.

6. If diamond-point nails split the wood, blunt the points slightly

with a hammer, clipper, or other convenient tool. If blunting does
NAILING BETTER WOOD BOXES AND CRATES 27

not prevent splitting, use nails of the next smaller penny size and

space them a little closer together. Lead holes about three-fourths

as large as the nail in diameter will also reduce splitting. Except

for very large members, predrilling is usually used for twentypenny

nails and larger.

7. In general, drive nails no closer to the edge of a piece than a

distance equal to one-half the thickness of the piece and no closer

to its end than the thickness of the piece. Smaller nails of a given

type can be driven closer to the edges or ends than larger ones

because they are less likely to split the wood.

8. To minimize wood splits, either stagger the nails or place them

in two or more rows.

9. AAHien nailing two pieces of lumber together facewise and at

right angles to each other, use nailing patterns similar to those

shown in figure 9. Use the patterns and recommended numbers of

nails for fabrication of crate panels where nails are clinched when

fastening pieces of lumber together flatwise. Use also when nailing

a piece of lumber flatwise to the edge of another or to the face of

a larger frame member.

10. When attaching two members so that their grain is parallel,

such as sheathing to struts, the number of nail rows is usually determined by the width of the surface in contact. Use one row, staggered when possible, for surface widths up to 2 inches, two rows for

widths from 2 inches through 4 inches, and three rows for widths

greater than 4 inches.

11. When nailing plywood to struts or other members, space nails

not more than 4 inches on center and stagger them in rows spaced

not less than % inch apart. Space the rows as far apart as possible

to increase the racking resistance of the joint.

12. Wlien nailing a 1-inch-thick frame member flatwise to a

2-inch-thick member to form a laminated beam or similar member,

use sevenpenny nails with the heads placed on the thinner member.

Space nails about 16 inches apart in the rows. Use two rows for

4- and 6-inch pieces and three rows for wider pieces. Stagger the

nails between rows. Longer nails may be used and then clinched.

Place nails about 1 to 11/2 inches from the edges.

13. Wlien nailing two members, each 2 inches thick, together flatwise, as when making laminated joists or beams, use twelvepenny

nails placed 1 to 11/2 inches from the edges, according to the width,

and approximately 16 inches apart in the rows. Use two rows of

nails for members 4 to 6 inches wide and three rows for wider

members. Drive nails in each row alternately from opposite sides

of the pieces. Stagger the nails between rows.

14. When three pieces of 2-inch lumber are to be nailed together,

first nail two of the pieces together with twelvepenny nails spaced
28 HANDBOOK 16 0, U.S. DEPARTMENT OF AGRICULTURE

and located as described in rule 13, except that all nails are driven

from the same side. Nail third piece to the piece that contains the

nail points witli twelvepenny nails spaced about midway between

the points of the ñrst nails.

15. In fabrication of sheathed crate panels, drive at least two

nails through each sheathino; board into each member it crosses. In

assembly, also, use at least two nails to fasten each sheathing board

to each framing inember, including skids.

16. When two pieces of plyAvood sheathing are butt jointed, position the joints at the center of a vertical or horizontal frame member. Nail the abutting edge of each sheet of plywood with two rows

of clinched nails, staggering the nails between rows.

RESISTANCE OF NAILS TO DIRECT AND LATERAL

FORCES

During handling and shipping of boxes and crates, the nails used

in their construction are subjected to direct-withdrawal and lateral

forces. The ability of nails to resist these stresses depends not only

on the species and condition of the wood but also on the kind and

type of nail used (fig. 4).

Withdrawal resistance is the resistance of a nail to forces that tend

to pull it from a piece of wood. Lateral resistance is the resistance

of a nail to forces applied at right angles to its length. Lateral resistance depends principally on the diameter of the nail, the density

of the wood, and the depth of penetration. A nail should penetrate

wood to a distance at least 10 times its diameter in dense species and

14 times its diameter in species of moderate or low density.

Direct-withdrawal and lateral forces can be calculated. Later sections of this handbook give methods used to determine the resistance

of nails under many conditions, and tables that list allowable loads

for various constructions.

Factors Affecting Nail Resistance to Removal Forces

In calculating withdrawal resistance, the allowable load primarily

depends on depth of nail penetration, the specific gravity of the

wood, and the diameter of the nail. Other mechanical factors, however, also affect withdrawal resistance; among these are surface

condition of the nail, type of nail point, type of nailhead, direction

of driving, whether the nail is clinched or unclinched, moisture content of the wood when nailed and while in use, and amount of wood

splitting.
NAILING BETTER WOOD BOXES AND CRATES 29

Surface Condition of Nails

The surface condition of nails is sometimes modified durincr the

manufacturing process to increase their withdrawal resistance These

modifications consist of surface coating, surface roughening, or sur-

, face deformation.

Surface-Coated Nails,—One of the most common surface treatments for nails used in the assembly of boxes and crates is cement

coating. In many specifications, use of cement-coated nails is required where nails are not clinched. In low-density woods, cement

coating adds materially to withdrawal resistance if it has been

properly applied. In denser woods, much of the nail's coating may

be removed Avhile it is being driven into the wood. Cement-coated

nails from different lots may vary greatly in withdrawal resistance

according to the way in which they were processed. Different techniques for applying the coating, and variations in the ingredients

used, cause large differences in the nail's resistance to withdrawal.

Under such conditions, cement-coated nails may have only a slight

initial advantage over bright nails. The greater withdrawal resistance of cement-coated nails is not permanent; it may drop off

within a few months.

Nails that have special coatings, such as zinc, are intended for use

where corrosion is an important factor in performance or appearance. Over a period of time, uniformly galvanized nails have some

advantage in withdrawal resistance over plain nails.

Roughened-ßhank Nails,—The chemically etched nail has a roughened shank and is somewhat superior to a cement-coated nail because its finish does not deteriorate as does the cement coating.

Under impact loads, however, the withdrawal resistance of an

etched nail differs little from that of the plain or cement-coated nail.

Sandblasted nails perform much as do chemically etched nails,

in that both types provide roughened surfaces that engage wood

fibers and resist withdrawal.

Deformed-Shanh Nails,—The majority of nails used in the construction of boxes and crates have smooth, cylindrical shanks. Any

variation from this form is usually intended to increase the surface

area without adding weight. Nails with barbed, spirally grooved,

annular-grooved, and other ty]3es of deformed shanks are widely

sold (fig. 4). In wood that does not change in moisture content

the withdrawal resistance of these nails, excei)t for some types of

barbed nails, is somewhat greater than that of a common wire nail.

Under changing moisture conditions, however, some of these nails

have much greater withdrawal resistance than the common wire nail.

In general, the annular-grooved nails sustain larger static-with-
30 HANDBOOK 16 0, U.S. DEPARTMENT OF AGRICULTURE

clrawal loads and the spirally grooved nails sustain greater impactwithdrawal loads than do other nail forms.

Some types of deformed-shank nails are more difficult to drive

than the plain-shank nails. This is especially so in the denser

species of wood and in species that have a marked difference between

springwood and summerwood.

Nail Points

The shape of the nail point has some influence on withdrawal

resistance. Nails with long, sharp, conical points will usually have

higher withdrawal resistance than nails with diamond points, such

as most common and cement-coated nails have (fig. 5). However,

the sharp-pointed nail's tendency to split the denser species of wood

lowers its withdrawal resistance. When such a point is blunted to

form a truncated point, there is less splitting than with the common

nail and, in the heavier woods, about the same withdrawal resistance.

In the less dense woods, however, nails with truncated points have

less resistance to withdrawal than diamond-pointed nails. Nails

with blunt or flat, untapered points do not split wood so easily.

They tear the wood fibers much more, however, and therefore have

lower withdrawal resistance than common wire nails.

Nailheads

Nailheads prevent the pieces holding them from pulling loose

when a force is applied. Nailheads vary in size and shape, but most

nails commonly used in box and crate construction have a round,

flat head. The sinker nail has a head with reinforcing fillet underneath, and this is called a countersunk head (fig. 5). The countersunk nailhead is strong enough to withstand the force required to

withdraw the nail from most species of woods. Nails with thin,

flat heads should not be used in the denser woods, because the nailhead may be broken off or damaged when the nail is driven, or

when stresses are applied. Wlien nailheads are damaged, the

strength of the joint is greatly reduced.

Direction of Driving

The resistance of nails to withdrawal is greatest when they are

driven perpendicular to the grain of the wood, as in side-grain

nailing (fig. 14). When they are driven parallel to the wood fibers,

as into the ends of a piece, their holding power may drop to as low

as 50 percent of the side-grain values. Slant driving has some advantages over straight driving when nails are driven into the end

grain of the wood.
NAILING BETTER WOOD BOXES AND CRATES 31

B

D

FIGURE 14.—Methods of nailing: A^ Through side grain of both pieces; ß, through

side grain into end grain; C, slant-driven nails; 2), toenailing; E^ clinched nails.

Toenailing, often used in the framing of large structures, consists

of driving the nails at an angle through the end or edge of one

member into another member (fig. 14). The best results with this

type of nailing are obtained when (1) the largest nail that Avill not

split the wood excessively is used, (2) the distance from the end

of the member to the point where the nail enters it is at least onethird the length of the nail, (3) the nail is driven at an angle of
32 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

30 degrees to the face of the piece it enters first, and (4) the head

of the nail is buried without excessively mutilating the wood.

Toenailing reciuijes greater skill but provides greater strength than

end-grain nailing.

Clinched Nails

Because tlieir pointed ends are bent against the wood (fig. 14),

clinched nails normally liave mucli higher Avithdrawal resistance

than unclinched nails. However, this advantage varies a great deal

with the size of tlie nail, the moisture content of the wood, and

other factors. This increase in Avitlidrawal i-esistance can vary from

50 to almost 450 percent. Nails clinched across the grain of the

board have approximately 20 percent more resistance to withdrawal

than nails clinched parallel to the grain. In box and crate construction, clinched nails are ordinarily used in fabrication of panels

or other container parts, and unclinched nails are used to assemble

the panels.

Overdriving

Overdriving of nails occurs most often in machine nailing boxes.

It may be caused by variations in sheathing thickness, by differences

in the density or species of the boards, or by improper setting of

the machine. Overdriving is undesirable in fabrication nailing of

container panels and maj^ be seriously detrimental in assembly of

parts. It reduces the amount of wood under the nailhead and consequently decreases the withdrawal resistance, especially when thin

sheathing is used.

Prebored Lead Holes

To prevent splitting of the wood, it is often necessary to drill lead

holes for the larger nails, especially in dense woods. Nails driven

into lead holes, which are usually about three-fourths the diameter

of the nail, have slightly higher withdrawal resistance than nails

driven without lead holes.

Nails in Plywood

One advantage of plywood is its greater resistance to splitting, so

that nails can be placed close to the edges. The nail-withdraAval

resistance of plywood is from 15 to 30 percent less than that of solid

Avood of the same species and thickness. However, for plywood

less than i/o inch thick, the high splitting resistance tends to offset

the lower Avithdrawal resistance as compared with solid wood.
NAILING BETTER WOOD BOXES AND CRATES 33

Placement of Nails

Figure 15 illustrates improper and proper placement of nails along

the edges of end sheathing or end cleats. The nails in .1 and B are

forced outward because of severe grain divergence. Improper sloping of the nail is shown in O, and D shoA\s the resuU of too close

edge and end spacing. In E, the nail was placed so far in from

the end that it missed the cleat. So placed it may damage the

contents. In F^ the nail is shown properly placed with respect to

the thickness of the cleat, but contact witli a knot has bent it outward, causing a "shiner." What happens when corner nails come

in contact with each other is shown in G, Finally, H shows a properly placed and driven nail.

Diameter of Nails

Nail diameter has much to do with both lateral resistance and

direct withdrawal resistance. The greater the diameter, however,

the greater the likelihood that the wood will split. This is especially

true of dense species when the moisture content of the wood is low.

Depth of Nail Penetration

The depth to which a nail penetrates is directly related to its

withdrawal resistance because the deeper the penetration, the greater

the contact with wood fibers. "Withdrawal resistance is calculated

on the basis of the depth of penetration in inches. In lateral resistance, a minimum penetration is required and no premium is

allowed for greater penetration. However, in actual handling of

crates and boxes, the same nail is often subjected to both lateral

and withdrawal stresses; hence good penetration has advantages.

Species and Density of Wood

Species and density of wood definitely influence the withdrawal

resistance of nails, and the two are generally related. In withdrawal tests - at the Forest Products Laboratory, it was found that

withdrawal resistance was more than doubled Avhen the density of

the wood tested was twice as high. For example, for an average

density of 0.33, the average withdrawal resistance of a cementcoated nail was 150 pounds, as compared with 440 pounds for an

average density of 0.66. These tests were made on wood that had

a moisture content of about 10 percent or less. The nail was withdrawn immediately after it was driven.

2 U.S. FoKEST PRODUCTS LABORATORY. NAIL-HOLDING POWER OF AMERICAN

WOODS. Tech. Note 236. 1958.
34 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

B

H

FIGURE 15.—Improper and proper nailing: A and ß, Nail bent by divergent grain;

C, slanted nail; D, nail too close to edge; E^ too great end spacing; F, nail bent . |

by contact with knot; G, nail bent by contact with another nail; jfiT, nail '\

properly placed and driven.
NAILING BETTER WOOD BOXES AND CRATES 35

Moisture Content of Wood

The moisture content of wood has a definite effect on the withdrawal resistance of nails, on ease of driving, and on the wood's

tendency to split. Changes in moisture content have an even greater

effect on withdrawal resistance. As green lumber dries, the withdrawal resistance of nails falls off. A nail driven into and immediately pulled from green Avood has almost 4 times the withdrawal

resistance it would have if it were left there 1 year while the wood

dried and was then pulled.

It is good practice to use wood that has a moisture content of

less than 19 percent for building containers. However, wood with

an extremely low moisture content is not desirable for containers,

since subsequent moisture pickup and loss will also reduce withdrawal resistance of nails and may cause the lumber to warp and

split.

How To Determine Nail Resistance

The two main calculable functions of nails used for assembly in

box and crate construction are their resistance to direct withdrawal

and their resistance to lateral stresses. In rouffh-handlino; tests of

TABLE 7.—Aiierage aUoioable loads ^ for nails in direct loithdraioals ^

{nails equal in diameter and, length to sinker nails)

Allowable load

Wood species

Sixpenny

Eightpenny

Tenpenny

Twelvepenny

Sixteenpenny

Twentypenny

Basswood, cottonwood,

true firs, pines (except

southern yellow), spruces, yellow-poplar, and

similar species

Western hemlock, red pine,

redwood, other species of

similar density

Pounds

18

25

34

38

59

Pounds

27

37

51

56

88

Pounds

35

48

66

73

114

Pounds

42

58

81

89

140

Pounds

49

66

93

102

159

Pounds

58

79

Soft elm, sweetgum, black

ash, soft maple, other

species of similar density _

Douglas-fir, western larch,

southern yellow pine,

other species of similar

density

White ash, beech, birch,

hard maple, oaks, rock

elm, other species of similar density

111

121

190

^ Based on normal conditions for containers.

2 When driven into side grain of seasoned lumber to a depth equal to two-thirds

of its length.
36 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

wood boxes, both types of failures have been noted. In drop tests

made with crates, the nail faihires noted in the joints between sides

and base were caused primarily by lateral forces.

Formulas have been developed "^ to determine the allowable loads

for direct withdrawal resistance and lateral resistance of nails.

Tliese formulas have been based on nails used for construction, as

for nailing of Avood trusses, and for fa])rication and assembly of

other structural units. They are applicable under conditions of

long-continued or permanent loading; however, they can be modified for loads of short duration or where the loading conditions

are not so severe. Thus, the formulas in the text and the allowable

load values for containeis given in tables 7 and 8 have been increased

about 20 percent above those for permanent loading. They are

considered satisfactory for loading and storage conditions to which

boxes and crates are normally subjected. Under extreme shipping,

storage, or handling conditions, however, allowable loads may be

reduced from those included in tables 7 and 8. Only side-grain

nailing is considered in the calculations that follow.

TABLE 8.—Average aUowdhle loads ^ for nails in lateral resistance ^

{nails having diameters equal to sinker nails)

Allowable load

Wood species

Sixpenny

Eightpenny

TenpennyTwelvepennySixteenpenny

Twentypenny

Basswood, cotton wood,

true firs, pines (except

southern yellow), spruce,

yellow-poplar, other species of similar density

Western hemlock, red pine,

redwood, other species of

similar density

Soft elm, sweetgum, black

ash, soft maple, other

species of similar densityDouglas-fir, western larch,

southern yellow pine,

other species of similar

density

White ash, beech, birch,

hard maple, oaks, rock

elm, other species of

similar density

Pounds

30

37

42

46

56

Pounds

41

51

57

63

78

Pounds

45

57

63

69

85

Pounds

54

67

75

82

101

Pounds

62

77

86

94

117

Pounds

81

101

112

123

152

1 Based on normal storage and handling conditions.

2 When driven in side grain of seasoned lumber, minimum distance of penetration equal to two-thirds of its length in the softer woods and one-half in the

denser woods.

^ U.S. FOREST PRODUCTS LABORATORY, WOOD HANDBOOK. U.S. Dept. Agr., Agr.

Handb. 72, 528 pp., illus. 1955.
NAILING BETTER WOOD BOXES AND CRATES

Direct-Withdrawal Resistance

37

The resistance of nails with circuhir, uncoated, plain shanks to

direct withdrawal depends on the specific gravity of the wood, the

nail diameter, and the depth of penetration. The following formula

may be used to determine the allowable direct-withdrawal load for

nails of any size under normal conditions of use typical of containers :

P = 1^80 G^D

where P is the allowable load in pounds per inch of penetration

into the member receiving the point (side grain of seasoned wood),

G is the specific gravity of species of wood, based on weight and

volume when ovendry,^ and D is the diameter of the nail in inches.

Table 9 lists the specific gravity, G, and G ^ for a number of woods

commonly used for the construction of boxes and crates.

Table 10 lists nail diameters and other data used in the formulas

for determining withdrawal values as well as for calculating the

lateral resistance of nails. If nails other than bright, connnon

TABLE 9.—Values for specific gravity (G) of ov&ndry loood used in

cdJculating direct-'withdrawal loads for nails

G G- G G^ G

5

G^

0.32 Ö. 06 0.47 0. 15 0. 62 0. 31

.35 . 07 .50 . 18 . 65 .34

.38 .09 .53 . 20 .68 .38

.41 . 11 .56 . 23 . 71 .42

.44 . 13 . 59 .27 .74 .47

TABLE 10.—Sizes of bright comnion vnre nails

Size (penny) Gage Length

Diameter

D Z)*

4_ 12Î4

11^2

lOJi

10>i

9

9

8

Inch

1/2

9

2%

2/2

2%

3

3/4

3/2

Inch

0.098

. 113

. 113

. 131

. 131

. 148

. 148

. 162

Inch

0. 0307

6_ . 0380

7 . 0380

8 .0474

9_ . 0474

10___

12

.0570

.0570

16._____ .0652

4 MARKWARDT, L. J., and Wn.soN, T. R. C. STRENGTH AND RELATED PROPERTIES

OF WOODS GROWN IN THE UNITED STATES. U.S. Dept. Agi'. TBCII. Bul. 479, 99 pp.,

illus. 1935.
38 HANDBOOK 16 0, U.S. DEPARTMENT OF AGRICULTURE

wire nails are used (such as sinker nails), the gage, length, and

other values will change from those in the table.

The sinker nail is the type most often used in the assembly of

boxes and crates. Table, 7 lists the average allowable loads for

direct withdrawal of sinker nails, or nails of equal diameter and

penetration, in box and crate construction. These are average

values, however, and values for individual species or pieces may

be somewhat higher or lower than those listed in the table. The

values in table 7 do not allow for any shank treatment, shank

roughening, or deformation.

Lateral Resistance

Lateral resistance is the resistance of the nail to lateral loads

applied at right angles to the length of the nail. For example, this

is the type of force to which nails used to fasten ends and sides of

a crate are subjected. As in the method used for determining the

allowable direct-withdrawal values, the specific gravity of wood

and the diameter of the nail must be considered in calculating allowable loads. The formulas are based on the penetration of an uncoated, circular-shank nail into wood. The nail should penetrate

into the lower density species a distance of about two-thirds its

length. In the higher density species, nails should penetrate to a

distance about one-half their length.

The following formulas can be used for determining the allowable

lateral resistance of nails driven into the side grain of various

species of wood. The values are based on stresses normally placed

on containers.

Species Formula

Basswood, cottonwood, true firs, pines (except southern yellow), ^

spruces, yellow-poplar, other species of similar density P=1,080D^

Western hemlock, red pine, redwood, other species of similar ^

density P= 1,350 D^

Soft elm, sweetgum, black ash, soft maple, other species of similar

density P= 1,500 D*

Douglas-fir, western larch, southern yellow pine, other species of

similar density P=l,650 D^

White ash, beech, birch, hard maple, oaks, rock elm, other species

of similar density P=2,040 D^

In these formulas, P is the allowable load per nail in pounds and

D is the diameter of the nail in inches.

The values for D ^ are given in table 10 for various sizes of nails.

Table 8 is included for the convenience of builders of boxes and

crates, and formulas need not be used except for special conditions.

The values are based on the sinker nail or other nails of equal

diameter.
NAILING BETTER WOOD BOXES AND CRATES 39

Wood Groups

Many species of wood are adaptable for use in the construction of

boxes and crates. The various species commonly used are divided

into four groups, largely on the basis of their density. Other factors

on which the groupings are based include their nail-holding power,

ease of working, and their splitting tendency. It is ahvays good

practice, in the construction of containers, to use species in the same

group for similar parts. For example, the sheathing of a crate

should consist of species in one group. The cleats of a nailed wood

box should also be selected from one group, although not necessarily

the same one. By doing so, the builder can use a single set of

lumber sizes and nailing practices. Most container specifications

designate the size of members and the size and spacing of nails

according to wood groups. The denser Avoods are used in smaller

sizes and fastened with fewer nails.

In the following groups are listed the various species of woods

commonly used for the construction of containers:

GROUP I includes the softer woods of both the coniferous (softwood) and broad-leaved (hardwood) species. These woods do not

split readily when nailed, have moderate nail-holding power, moderate strength as a beam, and moderate shock-resisting capacity.

They are soft, lightweight, and easy to work, hold their shape well

after manufacture, and usually are easy to dry.

Aspen (popple) MagnoUa

Basswood Pine ( except southern yeUow )

Buckeye Redwood

Cedars Spruces

Chestnut WUlow

Cottonwood YeUovv-poplar

Cypress

Firs (true)

GKOUP II consists of the heavier coniferous woods. No hardwood species are included. These woods usually exhibit a pronounced contrast in the hardness of the springwood and the

summerwood. They have greater nail-holding power than the

group I woods, but they tend to split more readily. The hard

summerwood bands often deflect the nails and cause them to protrude from the side of the piece.

Douglas-fir Tamarack

Hemlock Western larch

Southern yellow pine

GKOUP III consists of hardwoods of medium density. No

coniferous species are included. These woods have about the same

nail-holding power and strength as a beam as the group II woods.
40 HANDBOOK 160, U.S. DEPARTMENT OF AGRICULTURE

but are less inclined to split and shatter under impacts. Group III

species are the most useful woods for box ends and cleats. This

<iroup includes those Avoods from which most of the rotary-cut

lumber for wirel)ound and plywood boxes is obtained.

Ash (except white) SweetAiiin

Soft elm Syeaiiinre

Soft maple Tupelo

GROUP IV woods are the heavy liardwood species. They have

both the p:reatest shock-resistin<>: ca])acity and the greatest nailholding power. Because of their extreme hardness it is difficult to

drive nails into them and they have the greatest tendency to split.

They are the heaviest and hardest domestic woods and are difficult

to work. They are especially useful where liigh nail-holding power

is required. iNIany of them make excellent rotary-cut lumber for

wirebound and plywood boxes.

Beech O.-iks

Birch Pecan

Haekherry Rock elm

Hickory White ash

Hard maple

U. S. GOVERNMENT PRINTING OFFICE: 1959