United States 

Department of 

Agriculture 

Forest Sentice 

Northeastern Forest 

Experiment Station 

Research 

Paper N E-504 

New Techno 

for Low=Grade Hardwood 

Utilization: S~S 

by Hugh 

and Cha 
The Authors Abstract 

Hugh MI. Reynolds received his 

bachelor's degree in electrical engineering from the University of Minnesota in 1950. His engineering experience includes work in mining, 

heavy equipment manufacturing, 

and design of specialized research 

equipment. He did research work in 

drying of softwoods on the West 

Coast before joining the drying 

group at the Forest Products Laboratory in Madison, Wisconsin. For 

the past 16 years he has been working at the Forestry Sciences Laboratory of the Northeastern Forest Experiment Station at Princeton, West 

Virginia, doing research on the utilization of low-grade hardwoods. 

Charles J. Gatchell received his 

bachelor's degree in forestry from 

the University sf Massachusetts in 

1955. After a tour of duty with the 

U.S. Navy, he returned to the New 

York State College of Forestry at 

Syracuse University where, in 1961, 

he received his master's degree in 

wood-products engineering. From 

1961 to 1965 he was a project scientist in the product and process development project at the Forest 

Products Laboratory in Madison, 

Wisconsin. I-le is now project leader 

of the Low-Grade Hardwoods Utilization Research Work Unit at the Forestry Sciences Laboratory of the 

Northeastern Forest Experiment 

Station at Princeton, West Virginia. 

System 6 is a technology for 

converting low-grade hardwood to 

high-valued end products such as 

Furniture and kitchen cabinets. 

Among its concepts are: (1) a new, 

nonlumber product called standardsize blanks; (2) highly automated 

methods of converting the logs to 

blanks; (3) total processing of every 

board that contains a minimum-size 

cutting; and (4) minimized machine 

operator decisions and limited 

choices. While details of procedure 

and machinery may vary, the seven 

steps given are considered mandatory for profitable low-grade hardwood conversion. 

Manuscript Received for Publication 

17 February 1981 
Introduction 

Only the best part of the hardwood resource is presently used to 

make the solid wood parts in highvalued products such as furniture 

and kitchen cabinets. Conventional 

technology starts with the harvesting of large, high-quality trees of selected species. Only the highest 

quality logs, bucked from these tree 

stems, are sawed to standard hardwood lumber. And, only the best 

lumber (1 Common and Better) is 

generally used for the solid wood 

parts of furniture and kitchen cabinets. As a result, only a small part 

of the harvested hardwood resource 

is used in these finished high-vatued products. 

What is done with all the rest 

of the hardwood resource? Trees of 

low quality or less desirable species 

and the low-grade lumber from the 

better logs are used for railroad 

crossties, pallet parts, mine props, 

pulp chips, firewood, and many 

other products. However, these 

products have lower value than furniture and kitchen cabinets. The value of the end use of the raw material usually determines which trees 

can be harvested and processed 

profitably. 

A hardwood forest of small, 

poor quality trees has a very poor 

profit potential, and much of the 

hardwood resource in the eastern 

United States fits this description. 

Removing only part of the trees and 

leaving the best to grow to a mature, high-quality forest is often not 

profitable. The value of the poor timber removed often will not cover the 

cost of the timber stand improvement (TSI) work. 

Furniture and kitchen cabinet 

manufacturers also have problems. 

Hardwood forests do not yield an 

adequate supply of large, high-quaiity logs, and this causes a shortage 

of high-quality lumber. Shortages 

cause price rises. In the half-decade 

1975 to 1979, hardwood lumber 

prices rose 160 percent while hardwood furniture prices rose only 40 

percent. 

We believe that gradual, profitable conversion of low-quality, 

small-diameter farests to mature, 

high-quality forests is possible. But 

the low-quality, small-diameter trees 

that are removed must pay for the 

TSI work. The small trees must be 

profitably converted to high-valued 

products. This wilt require new technology and a new intermediate product. The new technology we call 

System 6. The new product is called 

standard-size blanks. Toget her, they 

can bring profitable conversion of 

the low-grade hardwood resource 

and reduce hardwood shortages. 

ideal mix of products are not readily 

available (Reynolds and Gatcheil 

1979). 

Four basic concepts differentiate the new System 6 technology 

from the conventional techniques 

used to convert hardwood tree 

stems to furniture and kitchen cabinet solid wood components. These 

concepts are: (1) a new, nonlumber 

product called standard-size blanks 

that is the output of the System 6 

process; (2) highly automated rather 

than manual techniques for convertBasic Concepts of System 6 ing logs to blanks; (3) total processing of every board that contains a 

An ovewiew of the System 6 minimum-size cutting; and (4) miniprocessing techniques starts with mized operator decisions and limitlogs that are 6 feet long (75 inches ed choices. Contrast these with 

actual) or 8 feet (99 inches actual), conventional techniques: logs are 

sound, and contain no more than 1- sawed to lumber. Lumber is sorted 

112 inches of sweep. Because this 

system is for low-grade, smalldiameter trees, diameter is restricted to 7.5 to 12.5 inches on the small 

end. Larger logs can be better handled with other techniques. We envision System 6 logs for furniture and 

kitchen cabinets to be part of a multiproduct bucking scheme where 

tree-length, low-quality logs are 

bucked to System 6 logs, pallet 

bolts, pulp bolts, or firewood. However, System 6 may well carry the 

entire cost of harvesting and processing where markets for such an 

by grade, with the higher grades 

being used to make furniture and 

kitchen cabinets. The lower grades 

are used for pallets and other less 

valuable products. Much of the con 

ventional processing is done manually and operators must choose 

the best of several options. 

Standard blanks have been developed by Araman et al. from an 

analysis of the rough part sizes required by 32 major manufacturers of 

kitchen cabinets and furniture. A 

standard blank (Fig. 1) is a piece of 

Figure 1.----Standard blanks 
solid wood (it may be of edge-glued 

construction) of a predetermined 

length, width, thickness, and quality. These blanks may be efficiently 

processed to the needed rough 

parts by simple ripping and crosscutting with a very small loss in kerf 

and end trim. 

Automated processing must be 

used to reduce costs and increase 

production. Current hardwood production techniques are essentially 

manual and require high-quality logs 

and lumber. A machine operator 

views a log or a piece of lumber to 

be processed and decides how to 

process it. Then he controls the machine as the operation is performed. 

For example, the lumber crosscut 

operator in a furniture rough mill 

has the task of cutting out pieces of 

specified lengths with a minimum 

of defect and making optimal use of 

each board. We views the board, 

moves it manually under the saw, 

pulls the saw through the board, 

and decides where the next crosscut should be made. Low-quality 

fumber has many defects, making 

decisions difficult and production 

slow. 

In System 6, manual processing 

is minimized. The crosscut operator 

examines each board, decides 

which one of three gang crosscutting options is best, and enters this 

choice into a gang crosscut saw. 

While the saw is automatically making the board crosscuts, the operator is examining the next board. 

With standard hardwood lumber, the higher grade boards are 

sold and processed for different end 

products from the lower grades. In 

System 6, however, every board produced from the &foot logs is processed through each step if it contains at least one minimum-sized 

cutting. This will be done without 

regard to any other board-quality 

factors such as grade or wane. 

Details of System 6 Technology 

The details of System 6 (Fig. 2) 

technology have been developed 

from numerous trials at our Meth0ds Testing Plant at Princeton, 

West Virginia. Several manufacturFigure 2.-System 6 begins with logs 

and ends with blanks 

ers of furniture and kitchen cabinets 3. Use automated cant sawing 

have evaluated the output of System to make boards. 

6 and found it satisfactory for the 

production of fine solid wood prod- 4. Use best drying practices. 

ucts. For System 6 to give the best 

results, seven sequential steps 5. Remove the majority of demust be considered: fects with automated cut-up. 

1. Divide the low-grade hard- 6. Bring pieces to specified 

wood resource into different round- size and quality with manual cut-up. 

wood products. 

7. Make standard-size blanks as 

2. Saw System 6 bolts to cants, the final product of the System 6 

not lumber. rough mill. 
A description of each of these 

seven steps follows: 

Step 1. Divide the low-grade 

hardwood resource into different 

roundwood products. Maximum use 

of the small-diameter, low-grade 

hardwood resource requires markets, such as pallets, pulpwood, or 

firewood, for species not used for 

furniture and those portions of desired species that are not adequate 

for System 6 processing because of 

crookedness, lack of soundness, or 

size. 

The System 6 bolt criteria are: 

Minimum 6 feet nominal; 75 

length: inches actual or 8 feet 

nominal; 99 inches actual 

Sweep: 1-112 inches maximum, 

any diameter 

Diameter: 8- through 12-inch diameter classes (7.6 

inches minimum to 12.5 

inches maximum diameter inside bark on small 

end) 

Quality: Sound and solid. Sound 

defects without limit. 

Small hardwood timber and 

low-grade hardwood timber are 

synonymous most of the time. We 

have made recovery tests with bolts 

having three or four clear faces and 

compared them with tests where 

straightness and soundness were 

the only criteria. 

Surprisingly, the poor-looking 

bolts had practically the same yield 

as the good-looking bolts. "Beauty 

was only skin deep" on the goodlooking bolts; the clear wood was 

only an inch or so deep. This thin 

covering of good wood is cut off 

during the making of cants and 

boards. 

The maximum sweep of 1-112 

inches over the bolt length controls 

the bucking decisions when treelength logs are cut to shorter 

lengths. Experience has shown 

(Reynolds and Schroeder 1978) that 

6 feet is the shortest length that will 

minimize crook and sweep while allowing an acceptable yield of long, 

clear cuttings. 

The lower diameter limit for 

System 6 material is the 8-inch diameter class (7.6 inches actual) on 

the small end of the bolt. System 6 

bolts are processed to two cants 

whose thickness determines the 

width of System 6 boards. Minimum 

cant thickness has been set at 3-114 

inches and a 7.6-inch diameter bolt 

is the smallest that will give two 3- 

114-inch thick cants. 

The upper diameter limits for 

System 6 bolts are set at the 12-inch 

diameter class (12.5 inches actual) 

on the small end of the bolt. Material larger than 12.5 inches is better 

processed with more conventional 

technology. Bolts at or near the upper limit will very nicely produce 

two cants that are 4 inches thick. 

Step 2. Saw System 6 bolts to 

two-sided cants, not lumber. Sawmills lose money sawing small factory grade 3 and poorer logs to turnber. Twenty percent or less of the 

lumber from these logs will be 1 

Common and Better-the profitable 

grades. Yet small factory grade 3 

sawlogs are, for the most part, the 

best available in the low-grade resource. The sawmills must make a 

different product-one that can be 

quickly and easily produced and 

one that can be sold at a profit. 

In System 6, sawmills make 

two-sided cants instead of lumber 

(Fig. 3). A marketing analysis (Reynolds and Gatchell 1979) shows that 

circular headrig sawmills should be 

able to make cants profitably if they 

use the following procedure: 

1. Load the bolt onto the small 

carriage and saw a 3-inch minimum 

wide face. 

2. Rotate the bolt 180". 

Figure 3.-Sawmills make 2-sided cants 
3. Make the second saw cut so 

that the bolt has the thickness of 

two cants plus a saw kerf. 

4. With the third and last saw 

cut make two cants, either 3-114 or 4 

inches thick, 

When large numbers of System 

6 bolts are to be sawed, automated 

sawmills that can make the two 

cants in one pass are practical. 

The requirement for 3-114- or 4- 

inch-thick cants reflects the needs 

of automated ripping. Boards wider 

than 4 inches may contain more 

than one cutting and this system is 

not designed to return a board for a 

second cut. We recommend only 

two thicknesses (all4 and 4 inches) 

because these cants require a minimum of sawing to produce a valuable sawmill product. 

Step 3. Use automated cant 

sawing to make boaads. One of the 

reasons that conventional hardwood 

sawmilling is costly is that logs are 

sawed to get the highest grade of 

lumber, This requires numerous 

turns of the log and the judgment of 

a highly skilled sawyer. Low-grade 

hardwoods do not contain enough 

high-quality material to permit such 

sawing for grade. Instead, they need 

a rapid, automated sawing technique to saw cants quickly into 

boards. Automated sawing means 

that the saw is set and runs without 

additional operator attention once 

the material is committed for processing. 

Circular gang resaws (Fig. 4) 

meet the automated sawing requirement quite well. They are relatively 

inexpensive, well proven through 

years of use in the hardwood pallet 

industry, and provide excellent accuracy. These machines require two 

flat parallel faces on the wood being 

sawed. Two-sided cants are ideally 

suited for these machines as the 

two rounded sides do not affect the 

sawing. 

Circular saws are put on the 

gang-saw arbor with spacers between them that determine the 

board thickness. With System 6, all 

boards from a cant are sawed to the 

Figure 4.---Circular gang resawing 

same thickness, As wilt be seen later, proper drying is very important-so important that we recommend stacking straight from the 

gang saw. Boards must be of the 

same thickness far optimum drying. 

Boards that do not have one minimum-size (1-1/2 inches wide x 15 

inches long) clear area are rejected 

before stacking, At/ other boards are 

used, 

Sawing a few boards from the 

cant and returning the remainde: of 

the cant for further sawing does not 

always work. Often there are 

enough growth stresses in smalldiameter hardwoods to cause a 

crook in the cant when afew boards 

are sawed at one time from one 

side. When the remainder of the 

crooked cant is sawed, the board 

nearest the fence is always thin on P 
sne end and of no value. We recommend a single-arbor circular gang 

saw with a large enough motor to 

saw all boards automatically in one 

pass. 

Stsp 4, Use best drying practices. The suwput of the gangsawing step is boards that are 3-114 

or 4 inches wide, about 6 or 8 feet 

long, and full of stresses that must 

be rerieved during drying. The drying step is crucial to the success of 

System 6. 

In our System 6 pilot plant at 

the Princeton Forestry Sciences 

Laboratory, a conveyor runs from 

the cant saw to the stacking jig (Fig, 

4), The boards are sticker-stacked in 

4x4~6-foot packages banded with 

polypropylene strapping and are 

brought "1 the air drying yard or to 

the forced-air predryer on the day 

the boards are sawed. 

System 6 drying experiments 

have shown that three practices will 

permit good drying and stress relief: 

First, boards should be stacked for 

drying immediately after they are 

sawed. Second, smooth 112-inchthick stickers on 2-foot centers 

should be used in stacking. These 

thin stickers keep the boards'surfaces from drying too fast initially. 

Third, 2,006-pound concrete slab top 

weights (~ii 5) should be used to ' 

prevent twist and cup in the top layers of the drying stacks. 

Some boards will crook while 

being dried. We have found it best 

to let this movement occur. Smooth 

stickers aid in this. When the 

boards are restrained to prevent 

crook, the stresses get locked in. 

Then when these boards are processed to remove defects, the cuttings that resutt will crook, Obviously, it is best to let this crook occur 

during drying to relieve stresses and 

get stress-free cuttings. Predrying 

and kiln drying schedules that include liberal equalizing and conditioning times will produce boards 

that are flat and stress-free. 

Figure 5.-Stacked board packages with top weight 

Step 5. Remove the majority sf 

defects with automated cut-up. System 6 processing results in narrow 

(3-114- or 4-inch) boards of only two 

lengths (6 or 8 feet). Most of these 

boards are of poor quality. In our 

trials to date, one-half to two-thirds 

of all boards were below the quality 

standards for 3A Common. Very little was as good as 1 Common. This 

is certainly much poorer quality 

lumber than that normally used in 

furniture and kitchen cabinet rough 

mills. 

We have developed techniques 

to get all that is good from these 

boards rapidly and efficiently. Gang 

crosscutting is followed by gang ripping. What separates our approach 

from the conventional one is that at 

each of these steps the operator inspects the workpiece and chooses 

the best of a very limited number of 

sawing options. Once these decisions are made, the board is processed automatically, These techniques have been developed so that 

all boards, regardless of quality, 

may be processed. 
Gang cresscutting 

A multiple-saw gang crosscut is 

used to make one to four pieces 

from each board (Fig. 6). The spacing between saws will depend upon 

the lengths of blanks that are to be 

made. The number of pieces generated will depend upon the quality 

and length of the board. 

The outer saws are used to trim 

the ends of those best boards (approximately 10 percent) that contain 

one full-length cutting. Mediumquality boards (approximately 20 

percent) contain a cutting that is 

long, but less than full length. The 

outer saws and one inner saw are 

used to cut these boards to one 

long piece and one short piece. 

Low-qua1 ity boards (approximately 

70 percent) are crosscut to three 

short pieces (6-foot boards) or four 

short pieces (8-foot boards). A degree of flexibility is gained by allowing the operator to turn the board 

end for end. yowever, once the 

combination of saws'to be used is 

chosen, the crosscutting is done automatically without further guidance 

from tho operator. This gang crosscutting procedure may be done rapidly by an operator with very little 

training. 

Gang ripping of acceptable pieces 

Pieces coming from the gang 

crosscut saw are accepted if they 

contain at least a minimum-size cutting (1-112 inches wide by shortest 

blank length to be made). Only one 

cutting will be made from each 

piece. To speed processing and 

ease the operator's decisions, we 

recommend cutting-width increments no smaller than 112 inch. In 

our work, we have standardized on 

cutting widths of 1-112, 2, 2-112, 3, 

and 3-112 inches. 

Each piece to be gang sawed is 

inspected to determine the better 

Figure 6.---Gang crosscutting saw, outfeed end (guard removed to show 

saw blades) 

6 
edge; this edge will be given a 114- 

inch dressing cut. The piece is 

placed in one of five pockets on the 

gang rip table (Fig. 7) so that the 

1/4-inch edge cut and the width cut 

to remove defects are made at the 

same time. The gang ripsaw operator can easily recognize into which 

pocket each piece should go because we use only five widths and 

each is separated by a 112 inch increment from the other. Pieces 

coming from the gang ripsaw must 

have edges of glue-joint quality. 

Any piece with large defects on 

both edges is unlikely to have a 

minimum-size cutting in it. It will 

therefore be rejected before the 

gang ripping step. Other pieces will 

have a better edge that may be discovered by flipping the piece from 

face to face. 

Gang ripping does not work 

well for boards wider than 4 inches 

because they may contain more 

than one cutting. Boards that contain more than one cutting require 

the operator to recognize both and 

make the necessary decisions to secure both, which is too complicated 

for rapid operation. In System 6, 

once the operator places the piece 

in a ripsaw pocket, he is through 

with it. Bolts up to 12.5 inches in diameter, when sawed to two cants, 

will yield the 4-inch maximum width 

System 6 requires. 

Step 6. Bring pieces to speeifled size and quality with manual 

cut-up. After gang crosscutting and 

gang ripping, the cuttings are in no 

more than five lenghts. Eighty percent or more of the defective wood 

will have been removed after step 5. 

However, there may still be some 

defects that need removal. A manually operated crosscut saw is used 

to remove end defects. Pieces are 

cut to blank lengths. A manually operated glue-joint ripsaw is used for 

salvage ripcuts when required. 

Figure ?.-Gang ripsaw 

7 
Step 7. Make standard-sine 

blanks as the final products of the 

System 6 rough mill. The furniture 

and kitchen cabinet industries use 

parts in thousands of different 

sizes. It would be almost impossible 

to convert low-grade hardwoods directly into these many different 

parts efficiently. Production runs 

would be too short and scheduling 

would be a vexing problem. Fortunately, standard-size blanks (Araman et al. 1982) solve these problems. 

Blanks are made to specified 

thicknesses, widths, lengths, and 

qualities. They are designed to be 

the rough size of the most commonly needed parts or to be multiples of 

the lengths and wigths of these 

rough sizes. Blank widths from 1-112 

to 3-112 inches in 112 inch increments work very well for narrow 

parts, or edge-glued wider blanks 

can be ripped back to the needed 

sizes. Clamp-carrier edge gluing 

with PVA glue at 200 psi (pounds 

per square inch) pressure has been 

used at our Methods Testing Plant 

at Princeton, West Virginia. 

Summary 

System 6 will require modified 

procedures all the way from the tree 

to the furniture rough mill. For 

greatest efficiency, tree-length logs 

should be bucked to multiple products including System 6 bolts, pallet 

bolts, pulp bolts, and firewood. System 6 bolts will be sawed to twosided cants to aid in the release of 

growth stresses and to control the 

width of boards that will be gangsawed from the cants. A maximum 

board width of 4 inches is recom- 

,vended. Boards from cants must be 

dAed immediately. Once property 

dritlrd, they will be converted into 

blarbks of specified length, width, 

thick,\ess, and quality. 

"The economics of System 6 has 

been covered elsewhere (Reynolds 

and Gatchell 1979; Gatchell and 

Reynolds 1980). There appears to be 

a sufficient economic potential at 

each step from trees to standard 

blanks. In addition, there are opportunities for secondary products: 

slabwood from the sawmill, rejected 

boards and slabwood from the cant 

gang saw, edgings, and trimmings 

from the kiln-dried boards, and 

green and dry sawdust--.all available for use as fuel or as inexpensive raw material for further processing. 

Literature Cited 

Araman, Philip A., Charles J. 

Gatchell, and Hugh W. Reynolds. 

1982. Meeting the solid woad 

needs of the furniture and cabinet 

industries: Standard size hardwood blanks. USBA For. Sew, 

Res. Pap. NE-494, 27p. 

Gatchell, Charles J., and Hugh W. 

Reynolds. 1980. Conversion of 

low-grade, small hardwoods ta a 

new raw material for the furniture 

industry with System 6. Proc, 

Symp. Util. Low-Grade South. 

Hardwoods-Feasibility of 36 Enterprises, Nashville, TN. 

Reynolds, Hugh MI., and Charles J. 

Gatchell. 1979. Marketing Iowgrade hardwoods far furniture 

stock-a new approach. USDA 

For. Serv. Res. Pap. NE-444, 7 p. 

Reynolds, Hugh W., and James 

Schroeder. 1978. Furnibre cuttings made from logging residue: 

the three-sided cant system. 

USDA For. Serv. Res, Pap. 

NE-417, 4 p. 
Errata Sheet (RP-NE-504) 

Page 5--para. 3, line II, "2,000-pound concrete slab top weights'' 

should be "1,250-pound concrete slab top weights" 
B 

Reynolds, Hugh W., and Gatchefil, Charles d. New technology 

for low-grade hardwood utilization: System 6. Broomall, PA: 

Northeask For, Exp. Stn.; 1982; USDA For. Serv. Res. Pap. 

NE-504. 8p. 

Sma!i! diameter (7-6 to 12.5 inches) low-grade hardwoods can 

be canver"rd to high-valued end products using System 6. 

Among its concepts are: (9 a new, nonlumber product called 

standard-sine blanks; (2) highly automated methods of converting tine logs to blanks; (3) total processing of every board 

that contains a. minimum-size cutting; and (4) minimized machine operator decisions and limited choices. Details of System 6 technology are presented. 

Keywords: hrniture manufacturing; lumber drying; hardwood 

dimension 
Headquarters of the Nodheastern Forest Experiment Station are in 

Broomall, Fa. Field laboratories are maintained at: 

@ Amherst, Massachusetts, in cooperation with the University of 

Massachusetts, 

Berea, Kentucky, in cooperation with Berea College. 

@ Burlington, Vermont, in cooperation with the University of 

Vemont , 

@ Nlawaw, OGo. 

New Hamphire, in cooperation with the University of 

New HmpMre. 

@ Hamden, Connwticut, in cooperation with Yale University. 

Morgantown, West Virginia, in cooperation with West Virginia 

University, Morgantown. * Orono, Maine, in cooperation with the University of Maine, 

Omno. 

@ Parsons, West Virginia. 

@ Princeton, West Virginia. 

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

New York College of Environmental Sciences and Forestry at 

Syracust! University, Syracuse . University Park, Pennsylvania, in eooperation with the 

Pennsylvania Shte Univemity. 

Warren, Pennsylvania.