United States 

Department of 

Agriculture 

Forest Service 

Northeastern Forest 

Experiment Station 

Research 

Paper N E-515 

A Classification System 

for Predicting Pallet Part 

Quality from Hardwood Cants 

E. Paul Craft 

Kenneth R. Whitenack, Jr. 
The Authors 

E. Paul Craft, research forester, 

received a B.S. degree in forestry 

from West Virginia University in 

1951. From 1951 to 1961 he managed logging and milling operations 

and was a field representative far 

heavy construction and industrial 

equipment manufacturers. He joined 

the Northeastern Forest Experiment 

Station's Forestry Sciences Laboratory at Princeton, West Virginia, in 

1962. 

Kenneth R. Whitenack, mathematical statistician, received a B.S. 

degree in mathematics from Concord College, Athens, West Virginia, 

in 1968. He completed graduate 

courses at North Carolina State University and Virginia Polytechnic Institute and State University from 

1968 to 1970, He joined the Northeastern Station at Princeton in 1967. 

Manuscript received for 

publication 30 duly 1982 

Abstract 

Producers who manufacture 

pallet parts from hardwood cants 

generally must purchase cants on 

the basis of existing structural timber grades that do not adequately 

reflect the quality of pallet parts 

produced 'from resawed cants. A 

system for classifying cants for pallet part production has been developed that more accurately reflects 

the parts grade mix that can be produced from each of the new cant 

classes. A formula is given to determine value relatives for each cant 

class. 
Introduction 

The early practice of the pallet 

industry for procuring hardwood raw 

material was to purchase stringer 

stock (mostly 2 by 4's) and lowgrade random lumber for deckboards from sawmills. As the industry developed, this practice changed 

to the purchase of cants or lumber 

of specified dimensions, in multiples of sizes required for individual 

pallet parts. This material was then 

resawed into pallet parts. 

In 1958 the National Wooden 

Pallet and Manufacturers Association (now the National Wooden Pallet & Container Association) published specifications which included 

a pallet and parts grading system 

that reflected the degree of strength 

and durability of four grades of 

commercial pallets. The pallet 

grades were based on the placement of various grades of parts in 

the pallet. The parts grades were 

based on the size, type, and distribution of defects that affect the 

strength and durability of the part. 

Although this system provided 

a method of assuring overall pallet 

quality and performance, it did not 

include a method of predicting pallet part grade yield from cants. Existing structural cant grades (National Hardwood Lumber Association [MHLA] Rules) were developed 

for application to whole pieces; they 

were not intended to reflect the 

grade mix of parts resawed from the 

pieces. For the last 15 years, pallets 

have been produced by specifying 

the minimum quality of parts acceptable in the pallet, As a result, 

pallet producers who do not have 

markets for a variety of pallet 

grades develop surplus inventories 

of off-grade parts. 

To help alleviate this situation, 

we experimented with a cant classification system (Interim) that is 

based on the same defect size, 

type, and distribution as the National Wooden Pallet & Container Association (NWPCA) parts grading rules 

(Appendix). This system enables a 

pallet producer to purchase grade 

classes of cants that will yield the 

grade mix of parts that more nearly 

meet the requirements for his operation, and thus help minimize the accumulation of off-grade parts. 

This paper describes the system of classifying cants for pallet 

part production and provides the 

grade mix of parts produced from 

each cant class. It also compares 

the newly developed cant classes 

with two construction timber grades 

from NHLA rules and one grade 

used by some industry firms (Appendix). In this report, the latter 

three grades are referred to as 

"Present." 

Procedure 

Four- and six-foot-long bolts 

from each of three species groups 

(yellow-poplar-cucumber, birchmaple, and red-white-chestnut 

oak) were sawed into 4- by 4-inch 

and 4- by @-inch cants. The cant 

width was dictated by the size of 

the bolt. No effort was made to balance the cant widths produced. 

Bolts were processed until a 

minimum of 10 cants were produced 

for each of four cant classes in 

each length category and for each 

species group. The cant classes 

were developed from the NWPCA 

grading rules for industrial pallets. 

Each cant also was graded by specifications by Present rules. 

Each cant was sawed into I- by 

4-inch pallet deckboards and 2- by 4- 

inch pallet stringers. The pallet 

parts were classified by a grading 

system based on the NWPCA pallet 

grading rules. 
Results 

A total of 295 cants were processed 

into parts. The cant distribution by 

classes was: 

Classification Cant class 

system 

1 2 3 Below grade 

Interim 33 23 24 20 

Present 24 66 5 5 

Graded pallet part yields by interim 

cant classes were: 

Cant class Part grade yield (NWPCA) 

interim 

1 2 3 Below grade 

1 59 23 8 10 

2 33 23 29 15 

3 10 19 37 34 

Below grade 10 11 14 65 

(See Table 1 for grade yields by species and length.) 

Table 1.-Parts yields by NWPCA grades from cants 

classified by the interim grading system, in percent 

Parts grade Parts grade 

Species cllaa~ samples 1 2 

;y...."" 

Number Interimcant of Number 

nlnerr of 

3 Be1ow samples 1 2 3 Below 

nradta nr~rlcr 

Yellow-poplar 1 

2 

3 

Below grade 

Maple 1 

2 

3 

Below grade 

Oak 1 

2 

3 

Below grade 

Total 1 

2 

3 

Below grade 

---a*- FOOT LENGTH - - - - - - - - - - - - 6-FOOT LENGTH - - - - - - 
Graded pallet part yields by Present 

cant grades were: 

Cant grade Part grade yield (NWPCA) 

Present 

1 2 3 Below grade 

1 48 27 14 11 

2 29 18 24 29 

3 18 26 18 38 

Below grade 3 3 14 80 

Differences in parts yield between species and cant length 

could not be distinguished statistically for cants classified by the 

Present rules. 

A series of statistical procedures were applied to determine the 

classification system that was more 

closely related to the quality of pallet materials within the cant. Results indicate the Interim system is 

more accurate by 33 percent. (The 

procedures and conclusions are 

given in the Appendix.) 

Relative parts values generally 

applied in the pallet industry using 

Grade 3 value as the base are: 

Below grade parts = 0.0 

Grade 3 parts = 1.0 

Grade 2 parts = 1.4 

Grade 1 parts = 2.1 

Where these relative values apply, the current value of each part 

by grade is determined by multiplying the current value of Grade 3 

parts by the relative value of the appropriate part grade. For example: If 

Grade 3 parts are worth $125 per 

thousand board feet (M bf), the 

value for each part grade would be: 

Part grade Relative value Grade 3 value Part value 

1 2.1 

2 1.4 

3 1 .o 

Below grade 0.0 
These relative values were used 

to develop Table 2, To determine 

the value of parts from cants classified by the interim system, the value 

of Grade 3 parts may be multiplied 

by the appropriate table value. For 

example, if the value of Grade 3 

parts is $125 per M bf, the mean 

value of parts that could be sawed 

from 4-foot cants by class for all 

species combined is: 

Interim Grade 3 Gross 

For example: 

If the parts price relatives are: 

Grade 1 = 3.0 

Grade 2 = 1.5 

Grade3 =1.0 

Below grade = 0.0, 

The mean value relative for a 

No. 1 4-foot-long hardwood cant 

graded by the interim system is: 

cant class Table value part value cant value (.47)(3.0) + (.27)(1.5) + (.15)(1.0) + 

dollarslM bf (.11)(0) = 1.965 

1 1.584 125 

2 1.383 125 

3 0.880 125 

Below grade 0.541 125 

Where the relative parts values 

differ from the example, value tables can be developed by the formula: 

198 If the value of Grade 3 parts is 72'88 $701M bf, the mean gross value of 110 

56.38 parts from No. 1 4-foot hardwood 

cants is $70 x 1.965 or 

$137.551M bf. 

Cant Value Relative = PI - 81 + 

P2 R2 + P3 ' R3 -+ P4 ' R4 

Table 2.-Interim classification system value relativesa 

Actual means (weighted) 

Interim class Length 

(feet) Nb Poplar N Maple N Oak M All 

Below grade 4 10 0.730 10 0.592 10 0.301 30 0.541 

Below grade 6 10 0.437 10 0.403 10 0.488 30 0.443 

All 

All 

%Value relatives based on the relation: Glass 1 parts = 2.1; Class 2 parts = 1.4; Class 3 parts = 1.0; Below grade parts = 0. 

For other value relationships, tabular values are calculated by the formula: P1. RI + PZ - RZ + P3 - R3 + P4 R4 

bN = Number of samples. 
Literature Cited 

National Hardwood Lumber Association. Rules for the measurement 

and inspection of hardwood and 

cypress lumber. Chicago, IL: Nat. 

Hardwood Lumber Assoc., 1978. 

115 p. 

National Wooden Pallet and Manufactu rers Association. Specifications and grades for hardwood 

warehouse, permanent or returnable pallets, Washington, DC: Nat. 

Wooden Pallet and Container Assoc., 1962. 18 p. 

Appendix 

Cant Quality Classification 

Since no published pallet cant 

grading system is available, we devised interim quality classes for use 

in the study. The following summarizes minimum specifications for 

each of four classes of cants: 

Class 1 

Sawed knots. Maximum dimension 113 face width. Multiple knot 

dimensions additive if within 3 

inches of each other. None over 112 

inch in edges or end 3 inches. 

Unsound knots and holes. 

Unsound or loose knots or holes 

may not exceed 116 width of cant 

face. 

Cross grain. Not greater than 

1:10 except in vicinity of knots and 

burls. 

Split, shake, checks. Singly or 

in combination not to exceed 113 

cant length, except 3 inches or less 

long are ignored, 

Wane. May not exceed 112-inch 

width on any edge of the cant. 

Manufacture. 75 percent of 

pieces must be at least of specified 

dimensions, and may not exceed 

114-inch thickness in excess of 

specified dimension; 25 percent 

may be within - 118 and + 114 inch 

of specified dimension. 

Class 2 

Sound knots. Maximum dimension 112 face width. Dimensions of 

clustered knots additive if within 3 

inches of each other. None over 1 

inch in edges or end 3 inches. 

Unsound knots or holes. Unsound knots, loose knots, or holes 

may not exceed 114 width of cant 

face. 

Cross grain. Not greater than 

1:6 except in vicinity of knots and 

burls. 

Splits, checks, shake. Singly or 

in combination, may not exceed 112 

of cant length. Those less than 3 

inches long are ignored. 

Wane. May not exceed %-inch 

width on any edge of the cant. 

Manufacture. 66-213 percent of 

pieces must be at least of specified 

dimensions, and may not exceed 

114-inch thickness in excess of 

specified dimension; 33-113 percent 

of pieces may be within - 118 inch 

and + 114 inch of specified dimension. 

Class 3 

Sound knsls. No size limitation. 

Unsound knots and holes. 

Unsound knots, loose knots, or 

holes may not exceed 112 width of 

cant face. 

Cross grain. No limitation. 

Splits, checks, shake. Singly or 

in combination, may not exceed 314 

of cant length; those less than 3 

inches long are ignored. 

Wane. May not exceed 314-inch 

width of any edge of the cant. 

Manufacture. All pieces must 

be within - 118 inch and + 114 inch 

of specified dimension. 

Below grade. Cants that do not 

meet Class 3 specification. 

Interim Grading System 

The interim pallet cant grading 

system has not been adopted by industry. Most cants currently are purchased by some variation of the following rules (Present). 

Class 1 

Sound end and faces 114-inch 

wane on not more than two faces. 

Class 2 

Sound-Square-Edge grade as 

defined in NHLA Rule Book, 1978, 

p. 74. 

Class 3 

Common Timbers Ik Industrial 

Blocking Grade as defined in NHLA 

Rule Book, 1978, p. 75. 
Statlstlcal Analysis for Value 

Relations 

The mean value relave (m) for 

the entire sample was: VR = 1.135 

with standard deviation (S) S = 0.61 12. If the cants are now classified by Present rules, the following 

results are obtained: 

Present class No, cants VF"I S 

1 70 1.499 0.476 

2 195 1.091 0.586 

3 16 0.884 0.474 

4 (Below grade) 14 0.21 4 0.368 

An analysis of variance 

(ANOVA) with a Duncan's Multiple 

Range Test yields the following results: 

1. No difference between 

Grades 2 and 3 

2. Pooled standard deviation -. 0.548 

Classifying the same cants with 

the proposed system (Interim) yields 

the following results: 

Interim class No. cants VR S 

1 97 1.646 0.399 

2 68 1.295 0.433 

3 70 0.824 0.399 

4 (Below grade) 60 0.492 0.457 

Similarly, an ANOVA with a 

Duncan's Multiple Range Test performed yields these results: 

1. All classes different 

2. Pooled standard deviation = 0.419 
A comparison of the two analyses reveals the following pertinent 

points: 

1. The lnterim system produces 

a more uniform distribution of the 

cants into classes. Note that with 

the Present system, 66 percent of 

all cants were grade 2 cants, only 5 

percent were Grade 3, and another 5 

percent were Grade 4. 

2. The differences between adjacent mean value relatives for both 

systems are: 

Classes Difference (Present) Difference (Interim) 

1, 2 0.408 0.351 

2, 3 0.207* 0.471 

3, 4 0.670 0.332 

*Not significant. 

Note the more uniform spacing 

between the lnterim system means. 

3. The standard deviations for 

the lnterim system are very consistent among classes. This is not 

true for the Present system. These 

are more variable with the largest 

standard deviation occurring in the 

Grade 2 cant class-the one that 

contains 66 percent of all cants. In 

fact, the standard deviation for this 

class (0.586) is nearly the same as 

the standard deviation with no 

grouping at all (0.6112). 

The smallest standard deviation 

(0.368 in Grade 4) occurs in a class 

that contains only 5 percent of all 

cants. 

Thus, the proposed system produces four distinct classes versus 

only three for the Present system. 

Further, the standard deviation is 

23.5 percent smaller than that 

yielded by the Present system. This 

means that in using the proposed 

system (Interim) we can more accurately predict the value of the material within a group of cants and 

within significantly narrower limits. 

Also noteworthy is that the Interim system of classification can 

explain 33 percent more of the variation among the value relatives than 

the Present system, i.e., 0.535 - 0.205 -- 0.33 or 33 percent. 
On page 4, column 3, paragraphs 2 and 3 

should read: 

The mean value relative for a 

No, 1 4-foot-long hardwood cant 

graded by the interim system is: 

If the value of Grade 3 parts is 

$70/M bf, the mean gross value of 

parts from No. 1 4-foot hardwood 

cants is $70 x 2.115 or 

$848.05/%/B $5. 
Craft, E. Paul; Whitenack, Kenneth R., Jr. A classification system for predicting pallet part quality from hardwood cants. 

Broomall, PA: Northeast. For. Exp. Stn.; 1982; USDA For. 

Serv. Res. Pap. NE-515. 7 p. 

A system for classifying cants for pallet part production was 

developed that more accurately predicts the pallet parts grade 

mix that can be sawed from cants than the structural timber 

grades that are now used. A formula is given to determine 

value relatives for each cant class. 

ODC: 739:834.9 

Keywords: Pallet cant classes; value relatives 
rs of the Nortkastern Forest Experiment Station are in 

Broomall, Pa, FeId laboratories are mairttained at: 

hwtts, in cooperation with the University of 

Berea, Kentwky, in cooperation with Berea College. 

Burlington, Vermont, in cooperation with the University of 

Vemont . Delawm, OM. 

ew Mmplhire, in cooperation with the University of 

Hamden, Comwtieut, in cooperation with Yale University. 

@ Morgantown, West Virginia, in cooperation with West Virginia 

University, Morgantown. 

@ Omno, Maine, in cooperation with the University of Maine, 

Orono. 

Parsons, West Virginia. 

Princeton, West Virginia. 

@ Syracuse, New York, in cooperation with the State University of 

New Uork College of Environmental Sciences and Forestry at 

Syracuse University, Syracm. 

@ University Park, Pennsylvania, h eooperation with the 

Pennsylvmla SCah University. 

@ Warren, Pewnsylvanlissl 

U.S. GCVEWEIEhT PRINTIKG OFFICE: 1982-605-024:51