Guide to use of wood as an alternate material in agricultural implements

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Title:
Guide to use of wood as an alternate material in agricultural implements
Physical Description:
Mixed Material
Creator:
Benson, A. O
Bell, C. C
Forest Products Laboratory (U.S.)
University of Wisconsin
Publisher:
U.S. Dept. of Agriculture, Forest Service, Forest Products Laboratory ( Madison, Wis )
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oclc - 263428400
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Table of Contents
    Front Cover
        Front Cover
    Main body
        Page 1
        Page 1a
        Page 2
        Page 3
        Page 3a
        Page 3b
        Page 3c
        Page 3d
        Page 3e
        Page 3f
        Page 3g
        Page 4
        Page 5
        Page 6
        Page 7
        Page 7a
        Page 7b
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
    Back Cover
        Back Cover
Full Text



(UIDE TO USE Of WOOC) AS AN AITEINAT[ MATEIIAL


IN AGIICUIJITUIAL IMPRL[ANTS

June 1942















OpEST tV|N




















UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
FOREST PRODUCTS LABORATORY
Madison, Wisconsin
In Cooperation with the University of Wisconsin






GUIDE TO USE OF WOOD AS AN ALTENATE MATERIAL
IN AGRICULTURAL IMPLANTS


A. 0. BENSON, Wood- Technologist
C. C. BELL, Forester

The past few months have witnessed the development of shortages in
several important raw materials used in farm equipment prior to the war. Dul
to the necessity not only of maintaining but even considerably increasing the
production of farm crops the shortage of such raw materials as iron, copper,
rubber, etc., cannot be permitted to stand in the way of rn output of essential
farm equipment.

The notable developments in farm equipment have come in the present
Generation largely because of the substitution of mechanical for animal power.
Steel has replaced wood in many places where it is the better material for the
use. At the same time steel in various forms has been used in some items
where wood can serve without much change either in service or design. Right
now it is important that all items of equipment be thoroughly analyzed with
the objective of usin. wood wherever it is adaptable in an effort to conserve
metals that are essential in the war program. It is not necessary to go be-
yond the uses where wood can be used to advantage to arrive ot totals that
represent substantial savings of metal and rubber.

On the basis of information, both from manufacturing. plants and
Laboratory research, subject matter is presented in this report that will be
helpful to manufacturers and to others looking for ooportunities to replace
critical materials.


Implement Parts of Similar Use Reouirements


Mrny implements in the agricultural machinery field hve parts or
r3semblies for which the requirements are similar. It is possible, therefore,
to group items on a use requirement basis even though the implements embody-
ing these parts m-.- be quite dissimilar. For instance, Guide Handles rr be
set up to apply to all wnl:irc- implements, such as plows, planters, cuitiva-
tors, hillers, rn,' diggers. The function of the aide handles for these var-
ious irplements is the same, and a material that is suitable for one is suit-
Pble for another, Naturaly plow handles must be capable of ,ithstonding
greater loads than garden cultivators. But, essentially, if wood will serve
for one it ,ill s rv-; for the other.

Table 1 is a listing of parts of similar service requirements where
wood has b'jen used with satisfaction in the past or where it is reasonable to
conclude that it can be used now as a means of reducing the drain on critical
mnjtals, At this time mere preference for a given material cannot bo a, decid-
in, factor; it is a matter of necessity to use the most serviceable )nd eco-
norical material that is available in quantity. Wood, right now, is a material
that meets these conditions in nui.-rous cases.
R1299








Table l.--Grouping of farm implement items on basis of similar
use requirement 3

Suggested form of wood stock


Tyrpical use groups :Lumriber : Dimen!"ion Plyo'ood
: stock ":or ibre
: board

Beam s .... ... ........................... x
plows, cultivators :
Conveyor chutes ............................. : 7
elevators, sellers, threshers :
Conveyor slats............................... .: x
binders, elevators, pickers, loaders
Floors...................................... : x
wagons, spreaders
Framework ................................... : x x
peanut pickers, poultry batteries, :
feeders, grinders
Han les, guide ................................: -
plows, cultivators, planters
Hitch parts.............. .............................. : X
wagons and other horse-dra-n implements
Hoppers .....................................: x x
"ills, fertilizers, lime sowers,
I" 'anzcers, feeders :
Le vrrs.. . ........ .................................
harrows, mowers, rakes, plows :
Panels ............. ....... ................ x x
hammer mills, incubators, threshers,
sellers
Poles or tongues............................. X : . ..x
wheeled implements, wagons :
Reels.............................................. : x x
binders, combines
Running gears ................. .. .......... : x
wagons, manure spreaders, rakes, drills :
Skids........ ......................... .. ... : x x
engines, portable freders and brooders :
Ta-Lnks s.......... .. .. ............... ................ ..: x
--'tering, storage, spraying, cooling :





Table 1 also indicates what seems to be the logical form of wood
product to use for the various parts. In solid form wood can be bought as
lumber in whatever quality classes or grades the manufacturer may elect to
use. As dimension or ready-cut stock it is available from both sawmills and
plants specializing in fabricated parts. Also millwork and furniture plants
may be looked to as potential suppliers of machined and reedy-to-use parts.

In sheet form plywoods and dense fibre and mineral boards will give
service in z.an- cases comparable to that rendered by sheet metal or solid
lumboTr. Where coverage is the chief purpose to be served plywood of two gen-
eral types based on adhesive used in manufacture is in the picture: (1)
Ordinary or interior type for equipment kept inside or operated outside only
in dry weather, and (2) weather-resistant or exterior type for equipment that
may be subject to longer periods of exposure to the weather or to other damp
conditions. The compressed fibre boards also come strongly into the picture
for coverage purposes. Especially where there is some fire hazard, as in
incubators, the min-ral boards, such as asbestos-cement or ypsur compositions,
have special virtue.

Designer may need alterin, to make changes from sheet metal to these
materials; curved surfaces may have to give way to flat ones, because neither
thick plywoods nor wall boards as normally manufactured will take extreme
curvature.

Wire used extensively in some poultry equipment may be replaced by
- ooden dowels or wooden lattice work.


Choice of Woods for Farm Implements and Eqpipment


Table 2 deals with the selection of species for the component parts
of farm implements and equipment. The list is not complete from the stand-
point of kinds of machines, but broad types of implements are represented.
For items not included some comparable machines appear in the list, Ind con-
clusions can be drawn with respect to the adaptability of wood for the use
and the kind of wood that would be suitable.

No attempt hos been made to list all the ,-oods that miiht be used for
the various implement parts. In some cases the use reqV.irments are not ex-
acting, and the list of satisfactory woods night Le exte:.nded to include aiiy
species commonly available. The recommendations for woods tke into consider-
ation a number of factors, namely, strength properties, ability to stay in
place, decay resistance, resistance to wear, availability, price, and others.
The choice of a wood is based on a combination of these factors. 0(Ocasionally
a certain wood is exceptionally adopted to meet aw outstandinO requirement,
as, for instan-*, the ability of hickory to withstand the vibration to which a pitman rod is subjected. Broadly, however, woods fall into prop-
erty groups, and within these groups there is often considerable latitude for
selection. There are the dense (or heavy)nardwoods, such as oaks, elus, hick-
ories, ashes, maples, birches; the nrondense(light-weight) hardwooc1s repres,nted
b:- such species as the cottonwoods, basswood, yellowpoplar: the dense noft-
woods, of whicb southern yellow eina', Douglas-fir, and western larch are
aro examples; the nondense softwoods, such as the soft pines, true firs,
spruces, and c, did's. nturnlly there are no s.hn'p lines serarating one -;roup


aI299-


-2-







from another, but on the average the dense hardwoods are s-tronger than the
nondense, the dense softwoods stronger than the nondense, and th;- donsri soft-
woods are stronger than the nondense harlhoods. Thus, there are cases where
a use requir-rent is such that the choice of wood may be from more t-in one
group. Where strength is a requirement, the dense hardwood:; or den,, soft-
woods include the suitable woods; -here the use is chiefly a rnvtter of cov-
eraf--o the suitable wood will most likely be found among th- nond"ns',- h-ird-
woods or the nondense softwoods.

Strength properties alone do not govern the choice of Toors. T7oods
with excellent mechanical properties may not be available in the .Aizus re-
quired, they may not be obtainable through regular lumber :n',r! they may be had only at prohibitive prices. Insofar as pos'aible these various
factors have been given weight in preparing table 2.


Alternate Names for Species


U. S. Forest Service nomenclature 'has been used here in li.stng
woods.. In some cases this differs from the co.mmonlr accepted commercial or
trade nomenclature. In order that there may be no misunderstanding< the chief
instances where differences occur are pointed out in the folloK-inr tabulation:

Nomenclature in Lists Conon Trade Yame

Red pine 'Lor,'-ay pine
Water tupelo Tuvilo
Sweetgum Red !zum
Baldcypress Cypress
Sugar maple Hard maple, rock maple

TWhen oak is listed it is meant to include the commercial ,-hite oaks or com-
mercial red oaks. White ash includes the ashes accepted in the "nito ash
group. Hickory includes the true hickories as distinguished from the pnecan
hickories.

Southern yellow pine includes principally longleaf, shortleaf, lob-
lolly, slash, and pond pines. The dense wood of any southern oin- ha", prac-
tically the same strength and characteristics as the dense -noJ of :n:- other
southern pine, and the lighter pieces are more or less rlilk. Ther, .h
strength values are important, lonzleaf pine. or ien!e *:outh:rn r... low ine
have been suggested. The term "dense", when. used in connec4+ion iti- 'ou-thern
yellow pine and Douglas-fir, refers to lumnber'. -r- ed und.;r :, dens" t,,
specification.

Spruce includes any of the spruces, re .-irlles of secios, 7-hich maPT
be available in lumber form to the fabricating pnlnt.

Rock elm refers to the true rock elm only, nnfl not to th, e]-; of
other species sometimes designated in the trade as rock lim.


R1299






Table 2.--Substitutions in specific implement parts and by kinds of rood


Equipment and parts Serviceable -voods
---------------------------------- ----------------------------------------
Bin-l'rs, combines
(grain, rice, etc.)


Decks


Divider board


Pitman rod
Lever

Rein guide
PRollers

Conveyor slats


Brooders
(poultry, battery type)
Fr'nmorork


:Oak, sugar maple, southern yellow pine,
: Douglas-fir
:Southern yellow pine, red pine, D las-
: fir, ponderosa pine, yellovwpoplbr,
: basswood
:Southern yellow pine, oak, "rhite ash,
sugar maple, yello" birch, cottonwood,
: yellowpoplar, Touglds-fir
:Hickory, sugar maple, whitee osh, ok
:Hickory, white ash, sugar maple, oak,
: yellow birch.
:TWhite ash, oak, surar maple
:Sugar maple, yellow birch, southern
yellow pine, oak
:Yellovr birch, beech, sugar maple, hickory,
: pecan, oak, -hite ash


:Oak, sugar maple, yellow birch, southern
: yellow pine, Douglas-'ir, white ash


-------------------------- -----------------------------------
Corn sellers
(hand and power)
Hopper, bang board :Cottonvwood, sweetgum, water tupelo, black-


: gum, southern yellow pino, Dou-las-fir
:Southern yellow pine, Douglas-fir


Cob stacker
Base


Frame :Oak, sugor maple, bech, white ash,
southern yello- pine, Dou.alaF-fir
Panels :Cottonioo, ypllo-'ponlr, 0s" oo
Grain and feeder elevators :Southern yellow pine, DouolTs-fir, ponderosa
: pine, rhitc pinr-, spruce

Cultivators (tractor, sulky)
Lever :Hickory, white ash, su;ar maple, oak,
: yello-" birch

Diggers (walking units)
andler beams, and levers :Oak, .hitrt -,fh, hick-ory


(a)


RiV'





Table 2 (continued)


Equipment and parts Serviceable woods

Drills


Hopper


Footboard

Wheels (see wagons)
Levers


:Yello--poplar, r;d'-ood, baldcyprcss,
southern yellow pine, w-stern hemlock,
cottonwood, sweet-um
:Southern yellow pine, oak, white a,
sugar maple, Douglas-fir

:Hickor;-, white psh, su' rrnaolco, oa.k,
yellow birch


Elevators (portable)
Conveyor chute :Southern yellow pine, Douglas-fir, western
larch, cotton-,ood, balicypr'i--s, redwood
Conveyor cleats :Oak, southern yellow pin i
Chute derrick :Oak, southern yellow pin(, Douglas-fir,
: western larch
Wagon hoist derrick :Oak, southern yellow pine, Dou&rlas-fir,
western larch
Hopper :Southern yellow pine, Douglas-fir,
: western larch

Ensilage and hay cutters
Feeder sides :Southern yellow pine, Dourl;os-fir, western


Conveyor slats


larch, yellowporILr, oak, 'hito ash,
: cottonwood, basswooa
:Oak, sugar mrplo, beech, yelio'-r birc,
: white ash, pecan


Feed grinders


Hopper :Southern yellow, pine, Dour1la,-fir,
yellowpoplar, baldcropr,-ss, western larch
Stand :Oak, sugar.manple, white ash, bch,
yellow birch
Skids :Southern yellow pine, Douwles-fir, western
larch, anr'." dense hrp rr ood

Feeders, hog
Hopper :Southern yellow pine, vretern larah,


: Dougas-fir, z'estern -mlci hit.
: pine, rod -ine
:South(rn yellow pine, Doulas-Fir
: Oak


Cover
Trough


Skids :Southern yello- pine, Dou'llp;-fir,
Western larch, any dense hx-rwood
-------------------------------------------------------------
Feeders, poultry
Stand and trough :Southern yellow pine, Dorcl' -fir, redwood


Sbaldcypres, cedar, cottonroo1, jionderosa
Spine, b-.*sood, sweetgum
--------------------------- -------------------
R1299 (b) c' j -


V





Table 2 (continued)


Equipment and parts Serviceable woods

Fertilizer distributors ......
Hopper :Southern yellow pine, baldcy.-press,
: Douglas-fir, red-;ood, cottonwood,
: basswood, white pine, yello-popl,-r


Hames :Sugar maple, yellow birch, beech, white ash

Hammer mills
Foed tables :Southern yellow pine, Douglas-fir, nn,
: dense hardwood
Side pnd top-plates :Any commercial softwood
Skids :Southern yellow pir.e, Douglis-fir, any
: dense hard&ood
Frame :Ok, white ash, s-i.a- mn-il0, -.1low birch,
: beech

Harrows, drag
Tooth bars :Oak, white as, sugar male
Drav bar :Oak, southern yellol- pine, vhit, ash,
hickory, Douglas-fir
Lever :Hickory, white ash, sug'ir 7-.1iple, oal:;,
yellow birch

Harrowvs, disc
Weight boxes :Oak, sugar maple, white ash
3..':iings :Sugar maple., persimmon, Aog7,ood
Lc -."rs :Hickory" -hite ash, sugar maD, oJ:,
yellow birch

Harro'-s, spring tooth
Draw bar :Oak, po1:thr'rn yellow' pine, hit. ash,
hickory, Do" .-las-fir
Lever :Hickory, white -in, sm-:,r moply, oa-k,
: yellowv'birch

Huy loaders
Conveyor cleats :Oak, -ugar maple, yellow birch, white ash,
hickory
Rake bars, deck, :,nd deck sides :Southern yellow pine, Douglas-fir

H r-., presses
Feedtable :Southern yellow pine, Dougles-fir, red pine
Division blocks :Southern' yello- pine, yellovronlnr,
..... Doujlns-fir, sveetgum., cotton'ooi, oak
Block setter head :Oak, sugar maple, white ash, hickory, any
dense hartdlood
Runnin- gear :Osk, white ash, hickory
rn-O": Su'.-,'r mnplo, in,' dense hardwood
---------------------- ------------------- ------------- ----------
R1299 (c)





Table 2 (continued)


Equipment and parts Serviceable woods

Hay rakes, sully
Tooth bars :Oak, sugar maple, white ash, Douglas-fir,
: yellow birch, southern yellow pin'
Wheels (see wagons)

Hay rakes, sweep :Southern yellow pine, DouTlas-fir, oak
Teeth

Hitch parts
beck yoke, singletree, double- :Oak, hickory, -hite Psh, su7ar mnple,
tree, evener, and draw bar : beech, yellow birch, rock elm, black
locust, ,reot1urm, dense soIthe.rn yollow7
pire, dense Do. lins-fir

Hillers, walking
Beam., handles, -uide :Oak, v',hite ash, hickory

Hog feeders, rotary
Hopper :Southern yellow pine, DouJTlar-fir, bald-
cyrpress, redw-rood, Iestern lrch

Incubators :Western redcedar, redwood, baldcyprmss

Lime spreaders
Hopper :Southern yellow pine, Dou-las-fir, bald-
cypress, cottonwood, yellov',poplar,
basswood, s'eet ur)
Wheels (see wagons)

M.nger partitions :Anyv' commercial softwood, ny, comrxercinl
hardwood

Manure spreaders
(see ',.3oris)

Mowers
Divider or swath board :Southern yellor- pine, Dou,-is-fdir,
cottonwood, yellov'poplar
Lever :Hicko 'y, -'hite ash, sugFrr maple, oak,
Yellow birch
Pitman rod :Hickory, su-nr maple, white ash, oak
Divider board stick :Oak, *'-rite ash, su-ar r'rile, yellow irch,
southern yellow" nine, Dou4las-fir
-------------------------------- --------------------------------------------
Pickers and h-sk,.rs
Elevators :So-uthern ycllo-- pipe, Doprlns--fir.
yello-rpopl'!r, cotton"-ood.
Conveyor flights :Cak, birt,, maple, beech
Gatherers :Oak, sugar maple, yellow birch, !oithern
: yellow pine, Do'i;li'-fir, reJ .ino

R1299 (d) continueu ad)





Table 2 (continued)


Equipment and parts : Serviceable woods
---------------------------------- ----------------------------------------
Pickers, peanut


Frame


Agitator bars


Fan housing
Hopper

Chute


:Southern yellow pine, Douglas-fir, oak,
maple
:Oak, maple, hickory, white ash, beech,
: yellow birch, southern yellow pine,
: Douglas-fir
:Yellowpoplar, cottonwood, basswood
:Oak, sugar maple, beech, yellow birch,
: white ash
:Yellowpoplar, cottonwood, bns-'-obd,
: magnolia


Trur-:s (see -.'Pons)
-----------------------------------------------------------------------
Planters, corn, potato, etc.
Hoppers :Southern yl.lorw pine, Douglas-fir,


Levers


cottonv`0x, 'io-.rpoplpr
:Hickory, ,'h s ite hsi, sag; r maple, oak,
: yellow birch


Wheels (see vragons)

Planters, garden
'Jheels (see wagons)
Frame, guide handles :Oak, rhite ash
Hopper :Cottonwood, yellovpoplnr, basswood,
white pine, red pine, ponderosa pine,
gum

Plows, cultivators, walking
Beams, stretchers, qnd guide :Oak, white ash, hickory, sv.gFr maple
hanJles
Frane :Any dense hardwood
Wheel (see wagon)
-------------------------------------------------------------------------
Plows, sulky and tractor
Levers :Hickory, -'hitc ash, sugvr ir.nple, oak,
: y,-llow birch
-------------------------------------------------------------
Poles, implement :Longleaf pine, Douglas-fir
(dense)
------------------------------------------------------------
Potato sorter and grader
Hopper :Southern yellow pine, Dougls-fir, oak
Rollers------------------------------
Rollers


Platform, draw bar :Oak, white ash, hickory, southern
Yellow pine, Dougls-fir
----R129 (e) continueu d)-------------------------------------

Rl 2T(e) (continriu ')





Table 2 continuedl)


Equipment and parts Serviceable v-oodfc
--------------------------------- -----------------------------
Skids, engine and other :Oak, southern yellow pine, Do,-zlas-fir,
: western larch, an:. dense hardwood
------------------------------------------------------------------------
Sleighs
Runners :Rock elm, oak, hickory, white ash

Sowers, hand
Hopper :Cottonwood, yellowpoplnr, bas-',roo, pines,
Douglas-fir, spruce

Spraying machines
(See tanks)
(See poles, implement)

Stanchions
Side bars :Sugar maple, yellow birch, b-cL, white
ash, oak, hickory, pocan

Tanks, watering
Storage, cooling :Baldcypress, Dou'las-fir, rI' -oo4, cedar,
white oak, southern yellow pine

Thills :White ash, oak, hickory, southern yellow
: pine

Tongues or poles
(See ',,,a-ons, tongues)

Wagons, spreaders


Floor boards


Sills

Scoop boards


End ladders


Side and end boards



Footboards
Seat


:Tde-grt ine1 Douglas-fir, -odg--rained
Southern yellow, nine, r-!':i.:d ",es-
Stern lprch, yellow' birc, ;vwet birch,
whitewash, beech, oak, surr rn.ple
Southern yellow- pi-e, Douxlas-fir, oak,
: hickory, pecan, ash
:Edy,-- -rpined southern yellow pine, edie-
grained Douglas-fir, ed .-Fr in' ws-
tern larch, any dense hardroodI
:Southern yellow pine, Douglns-fir, ook,
whito a;h, hickory, yello,-, birch, beech,
sug'r' maple
:Yellovoopilr, cottonwood, barvs'.o3, onk,
White ash, southern yellow pi-e, Dounlas-
fir, baldcypress, yellov, birch, sru-, r
Simple.
:Same as'for floor boards
:Yellowpoplar, white pire, cot tor,,ood,
Sbasswood


Cleats (see hounds, below) :
R129 (f) (otinu d)-----------------------
R1299 (ffoolitinuoT)




Table 2 (continued)


Equipment and parts : Serviceable woods
---------------------------------------------------------------------------


Wagons, spreaders, trailers, trucks:
Hubs

Felloes and rims

Spokes

Tongue and reach

Axles :]

Bolsters

Bolster stakes
Sand bolster :

Hounds, and slider bar :

Brake bar
Brake block
Brake bar han.--er


Waterers, poultry
Stands

Troughs


Rock elm, oak, black locust, sugar maple,
sweet birch, yellow birch
Hickory, oak, white ash, rock elm,
yellow birch, sugar maple
Hickory, oak, rock elm, white ash, yel-
low birch, sweet birch, sugar maple
Oak, white ash, southern yellow pine,
Douglas-fir
Hickory, white ash, sugar maple, oak,
pecan, yellow birch
hickory, oak, white ash, sugar maple,
pecan, yellow birch
Same as for hounds
hickory, oak, pecan, sugar maple, white
ash, yellow birch
liickory, oak, white ash, rock elm,
yellow birch, sugar maple, beech
Same as for axles
Same as for axles
Uickory, white ash, sugar nimple, oak,
pecan, yellow birch


:Southern yellow pine, Douals-fir, red
Spine, bildcypress, redwood
:Redwood, b'ildeypress, cedar


Wheelbarrows


Handles :Oak, hickory, sugar maple, ,ellow birch,
: white ash, elm
Trays, garden type :Basswood, yellowpoplr, cottonwood,
sweetgum, water tupelo
Trays, utility type :Elm, oak, sugar maple, beech
--------------------------------------------------------------------------
Windmills
Platform :Baldcypress, redwood, white oak, Douglas-
fir, southern yellow pine, western


Sails


Arms
Tower


Pump pole

Ladder

Sucker rods

Pump jack
R1298


Slirch, cedar
:Baldcypress, yellowpopl3r, spruce,
basswood
:Oak, southern yellow pine, Douglas fir
:Southern yellow pine, Dou41as-fir, wes-
Stern larch, oak, sugar maple, yellow
birch, white ash
:White ash, hickory, oak:, southern :.-ellow
: pine, Douglas-fir
:Southern yellow pine, oak, sugar 2 atple,
yellow birch, Douglas-fir, white ash
:White ash, hickory, southern yellow pine,
: Douglas-fir
Southern yellow pine, Douglas fir..


(g) (concluqcd)





Availability of Species


During the war period it is impossible to state with certainty the
extent to which the individual species are available for farm implement and
equipment manufacture. As demand for wood increases with ex.ani'n. military
uses and substitution becomes necessary because of limitation of use- of
critical materials the supply situation is constantly chonning. A ",ood that
is available in abundance today may be less available tomorrow. The recent
order freezing certain grades of softwood construction lumber is n case in
point. However, the shop and factory grades are not frozen so that the sip-
ply although narrowed in range may still be sufficient in quantiity in4l
quality to meet any demands that might come from farm implement manufacturers
and other users of lumber in remanufactured form.

Certain hard-7oods have been relatively scarce for some timr.e because of
abnormal demand for special war uses. White oak, wVhite ash, and yellovr birchi
are examples. There are other woods that will give comparable: servic-.

Some woods are abundant in certain localities, anrA yet not -enerally
available throughout the territory in which the farm implement indutr: is
largely concentrated. For instance, black locust is abundant in tnec
Appalachian region from Pennsyrlvania south into Georgia nnd AlAbrma ind in
parts of the Ohio Valley, yet it comes into the general luu'.r rnr!ets only
in small quantities because it is not a general purT)pose Wood.

Certain woods with excellent properties are avilo'ble in the sizes
required only at prohibitive prices. Among such' ere do.-ood, pcrsi-Tron, and
osageorange. Unless a manufacturer is unusually well located v,'ith aspect
to supply of these woods they should be considered in the unavailable class.


Optional Forms of Wood Stock and Sources of Supply


A wood user has much the same option in buy'ing stock as h'Ia the metal
user. He may buy material in uncorked form or he may buy parts for nis erod-
uct in machined form readlr to assemble at his factory. There, aro .:an- sub-
stantial sawmills and !oodwork1ng plants that are equipped -'ith ir:: kiln:; nd
machinery that are capable of doing just as Pood a job as the factories them-
selves. For farm equipment plants without wood-'orkinq machinery or ;nen fa-
miliar with woodworking the purchase of rtady-cut parts offers a solution to
the problem of changing from metal to vrood. For factories equip-eO1 '-ith fa-
cilities for working wood the opporturity to buy parts cut and c'riod to their
requirements has some distinct dva:ntagces. It enables them: to increase;
production at a rapid rate without overloading their wood prep'ratory shops.
Another decided Pdvuntage is elimina-tion of a large lumber inventory with
the many items of direct and indirect costs that go with it. Tedvntage
of a substantial back-log of lumber is that the factory is more or loss in-
dependent of extreme fluctuations in prices and there is also les; danger of
a breakdown in supply flowing to the assembly shop. At the pret.;nt time
ceiling prices on most lumber items have eliminated the danger of run-a'"j
prices, so that the argument for a large lumber inventory lose? much of its
force.


R129g


-4-





On the basis of a thousand board feet, cuttings bought ready-cut
and cuttings obtained by a factory from lumber in its own shop should not
vary greatly in cost. The advantage is usually on the side of read.-cut
stock as a factory operator who has included all of his costs knows. It is
the advantages aside from apparent costs that often strengthen the case for
ready-cut stock.

A convenient method of locating sources of supply for lumber and
ready-cut stock is through lumber trade associations. Among the lumber
associations important from the standpoint of farm equipment manufacturers
ore the
National Hardwood Lumber Association
59 East Van Buren St., Chicago, Illinois

Northern Hemlock & Hardwood Manufacturers' Association
Oshkosh, Wisconsin

Southern Hardwood Producers.
805 Sterick Building, Memphis, Tenn.

Northeastern Lumber M.inufacturers' Association
271 Madison Avenue, New York, N. Y.

Southern Pine Association
Interstate Bank Building, NeT Orleans, La.

West Coast Lumbermen's Association
564 Stuart Building, Seattle, Wash.

Western Pine Association
510 Yeon Building, Portland, Oregon

Appalachian Hardwvood Manufacturers, Inc.
41l Walnut Street, Cincinnati, Ohio

Hardwood Dimension Manufacturers' Association
229 Heyburn Building, Louisville, Ky.

A r-qu:,st to the National Lumber Manufacturers' Association, 1337
Connecticut Avenue, N. W., Washington, D. C., will ilr-'riys bring pertinent
inform-Ation whether the inquiry concerns hardrvoods or softwoods.


Ply,-ood

Were circumstances normal resin-bonded plywoods would be available
for many uses. They are especially us-,ful where& cove r,- is the chief
1requirnment. Such plywoods rr so extremely resistant to moisture that
th::" will withstand prolonged exposure to weather. however present mili-
tary demnnds for this type of plywood plus the demand for the materials
from which the synthetic resin gluce.s are made create p situ-otion -hich
leaves limited quantities for ordinary civil ui:es.


-5-






Where equipment is used indoors or is exposed to the weather for
only short periods plywoods formed with other glues will give good service.
For some uses plywood has qualities superior to those of solid 7ood. It
swells and shrinks less than solid wood when exposed to changes in unirrdity.
It is effectively resistant to checking. It can'be obtained in wide, long
panels, and where rigidity is a factor large, unbroken sections hove a de-
cided advantage over sections of the same size composed of a number of
narrow pieces not edge-glued.

Plywoods are available in various thicknesses and of different woods.
Among the sources for information on plywood supplies and uses are the
Hardwood Plywood Institute, 205 W-'st Wacker Drive, Chicago, Illinois, and
the Douglas Fir Plywood Association, 1203 East D Street, Tacoma, Wa ;hin:-ton.
Most local lumber distributing agencies can be relied on for information on
plywood that will be helpful to prospective users.


Fibre Boards and Wall Boards

Of fibre boards there are several that might be considered as al-
ternates to plywood. Some of these are hard and stiff, and serve rucll for
coverage. Properly coated they will stand severe exposureo to the weather.
They may be obtained in large panels, 4 feet by S feet, and in thicknesses
from 1/9 inch up.

Another type of wall board is that made from minerals or minerals
combined with wood or other fibres. Examples of these are gypsumr. boards and
asbestos-cement boards. These are highly fire-resistant, and are especially
adaptable to uses where the fire hazard is a factor to be reckoned with.

Information on fibre boards or wall boards is generally available
from local building material supply agencies.


Classification of Woods
According to Important Properties


Table 4 shows in approximate terms the property relationships of a
number of the commercially important woods. Provided a prospective user
kno-'s the requirements for a specific purpose the table ra: b usd as a
guide in the choice of woods for items not included in table 2. usually the
choice is determined by a combination of two or more properties alon with
the factor of price and availability. Where requirements are not exacting
price may be more important than properties of th' woods, and agaig9n ,"'here
two or more woods have almost identical property ratings, advantage as
represented by price may outweigh other considerations.

For the more complete information on wood properties that every d1-
signing engineer should have there is available from the S-.-.p rint- ''nJcrnt of
Documents, Washington, D. C., the "Wood Handbook," price y3 c, nty; (cash or
money order, stamps not accepted). It deals in detail with wood as a mate-
rial of construction, and contains data for its use in design -n! specifi-
cations.
R129g -6-








Use of Wood in New Forms and by Neov' Methods


New forms of wood products, new processes, new treatments, new
equipment, and new fastenings have come into existence since wood began to
recede from use in agricultural implements. With the exception, however, of
the structural use of plywood and dense fiber boards and i-nproved kiln-dry-
ing facilities the prospective user or designing engineer should not put too
much reliance on using wood in some radically new form. This is not to min-
imize the importance of the new developments, but to focus on the obvious
fact that the important substitutions of wood for other materials in the
implement field for the immediate present will be through the use of conven-
tional materials and forms. The fact that often critical materials are in-
volved in the newer developments or that supply facilities cannot b set up
at this time is the main reason why the designer must adhere larely to
standard form. There are opportunities for the designer to show ingenuity
and to devise short cuts using standard readily available forms of material
without relying on forms more difficult to obtain.

In addition to-the exceptions referred to above there are, however,
certain rapidly growing practices that ma:. be expected to find, Cpplication
in this field more readily than others. Reference is made to: (1) Special
metal connectors to supplement bolted joints in heavy structural mrnmbers.
Such connectors are available on a license basis from one supply organiza-
tion. (2) The lamination of curved or straight members, with moisture-
resisting, cold-setting adhesives, by nail, clamp, or machine pressure.
Glued, laminated products are available from a few producing plants ;vhich
specialize in this business, or they con be made f.iirly readily by thc user.
T7,o uses in which laminated construction is kno"'r to hrve been used in the
agricultural equipment field are for toniques Pnd quite recently for heavy
hoops for storage bins and silos.

1Aysterious formulae for impregnations or coatings to eliminate the
swelling and shrinking of wood have been commonly promoted, but wood still
swells and shrinks. Soundly compounded, heavy-bodied coati-'s are effec-
tive in reducing the rate of dimensional ch-nge but not th amount of change.
Considerable progress has been made in the development of coatIns that re-
duce end splitting of lumber and logs incident to storag-r or sCasoninp.
Fairly good fire-reta.rdant paints are available for special usages if re-
quired. Information in this field can be supplied upon request.

7ood plastics, plasticized wood, compressed vrood, and similar new
products have special utilities and promise, but for quantity nondefense'
usage at present are practically out of consideration because of the dif-
ficulty of obtaining accessory materials or equipment needed in their pro-
duction. As a substitute for brass in small >'earings or similar parts cer-
tain products in the laminated plastic field do come in for consideration
if the need is sufficiently important.




-7-
RI2,






Table 4.--Broad classification of woods according to
characteristics and properties

(A, among the woods relatively high in the particular respect listed;
B, among the woods intermediate in the particular respect listed;
C, among, the woods relatively low in the particular respect listed)


Kind of wood


: Working and behavior char-
: acteristics


Str.mn : properties


: : : : : : : :
S0 0 T ^r4- 0
( : :c o .: *:.< : : .+ :
:~( 0:. ("1 .,
T:J 4-1q (4 r-1 Id U) 0 0 0 '). (
0 'H fj 91 0a ;q -1 0 *t, p 44J- 4-) ^ ;
4-5 0ci Q o. HM 44: 4o ^ 4-3 : n. (D.- 40 >
4- : 0 4. 'r 0 '4 0
0 [0 Cd PI M- -. -d $A 'C ) o.o
P4 0i D^ < :ar- i c 1) () pa). Zd^ *- p-H
: .^
P40 .* P Cd ed ca (L. -J C' : k' ,; fi. T (n. 4^ .-) Cb 0
P-I---- ------- '--- C I--------------
S2:3 4 5 : 6 7: 9 :10 :11 : 12: 13 : 4
- - - - - - - - - - - - - - - - - - - - - - - - -


Ash, white.......... :
Ash, black........... :
Baldcypress......... :
Basswood............ :
Beech ............... :
Birch, yellow........
Cedar, northern white:
Cedar, western red...:
Chestnut.............:
Cottonwood...........:
Douglas-fir..........
Elm, soft ............:
Elm, rock............
Fir, balsam..........
Fir, white...........:
Hackberry............:
Hemlock, eastern.....:
Hemlock, western.....:
Hickory, true........:
Hickory, pecan....... :
Larch, western....... :
Locust, black........:
Maple, hard..........:
Maple, soft .......... :
Oak, red ............. :
Oak, wnite...... .. :
Pine, ponderosa......
Pine, southern yellow:
White pine group: :
Northern white...:
Western white....:
Sugar pine.......:


:..: A C
C
A: B : A
:..: C : C
:..: A : C
.. A C
A C : A
A: C : A
:..: B : A
:..: C : C
C: B: B
.. A B
..:...: B
B:...: C
B: C: C

B:B : C
B: B : C
:..: A: C
C



C: A: B
.. A C
:..: A: C
:.. A C
:..: A C
:..: A A
B: B :(2)
C:A: B

A: B :(2)
A: B :(2)
A:... :(2)


(continued)


R1299







Table 4 (continued)


Working and behavior char- Strength
Kind of wood. acteristics properties


q .I
S S p *rS a ui Sl
C Z : : : U 0 0
1 00 00 ,D o -
H P4 03'-
9 S:.. 0 O .H.o 0 *: o .: : :g :4
-d I'd f,* Q) 1- 0) sa; 0- aoj p^ T M oo
: : ,?.: ^ .( : '. : m o:3( : a .: $ -4: o- : anj: 0
0 x " o r10 ( r, 4 P :
4 d. C, c, jci ;L 14: 0
--------------------------------------------------------------------------------------
1 : 2: 3: 4 : 5 : 6 : 7: 9 : 9 :10 :11 : 12 : 13 : 14

Redrood ............... B 3: A A : : A: B A A B A: B
Spruce, eastern .......: C: 3: B : A : B : B: B : C : C : : B : B : B
Spruce, Sitka...........: : B: B : A : B : B:... C : C : B : A : B : 3
Spruce, Engelmann.....: C: C: B : A : B : B: C : C : C C : C : C : C
Sweet u: ............... .: B: B: C : C B :..: B : B : B : B : B
Sycnmor-...............: A: A: C C :C :..: A C :3: B 3 3 B
YelloTpoplar... .........: C: B: B A A ..: 3 C 3 C : C
Water tupelo ..........: A: A: 3 C : C :..: A C : C : : '3 : 3


IExclusive of the all-henrtwood grades that are aveilpble on j ecial order
in birch, cedar, bnldcypress, Douglas-fir, sweetgu-m, southern yellow
pine, and redwood.
-Conflicting opinion and absence of adequate test data preclude P definite
rating. Placing reliance on high decay resistance is not rco 'r-,.,tded
when this wood is used untreated.

(concluded)
R1298





Lumber Grading


Softwoods

Softwood lumber is graded under rules issued by the various regional
lumber inspection burpau8 or associations. The following table indicates
where to go for information on grading the various species referro.d to in
table 2.


Lumber Inspection Agencies



Kinds of wood : Agency or association : Address of
: sponsoring grading rules as: nsociption

Southern yellow pine :Southern Pine Inspection :Canal ?ui1iri,
:Bureau :V.e Orlenns, La.
----------------------------------------- ~----------------------------------
Baldcypress :Southern C.-press :2 P'rr'tt ]'tional
I:nufacturers' Assn. B?,n: ilrl.in;,
: :JJcksonville, Fla.
-------------------------------------------------------------
Douglas-fir, western hem-:P-cific Lumber Inspection :364 Stuart }3uildin",
lock, western redcedar,: Bureau :Seattle, Washington
Sitka spruce
-------------------------------------------------------------
Eastern white pine, red northern n Pine :4435 "entworth Avenue,
pine, eastern spruce : .nnufacturersl Assn. :!;inneapolis, 'irn.

Eastern spruce, northern :Northeastern Lumber :271 'adison Ar',nue,
white pine, red pine Ma: manufacturers Assn. :_,ew York, 1. .

Redwood :California Redwood Assn. :40r. Vont-aoim ry Street,
S:S'n Fr'-ncisco, Calif.
- ---------------------------------------------
Ponderosa pine, western :Western Pine Associa.tion :51C Y.o: BTildin,,
white pine, western :oPortland, Oreg n
larch, sugar pine,
r'estern redcedar
-----------------------------------------------------------
Eastern hemlock :Northern HeL-.lock and :P. 0. Box 104",
: Hardwood M.nufactiurers' :Oshkosh, Wis.
: Association



Hardwoods

Standard grading rules for grading all conmcrcirellv irrort-nt haTd.-
woods are issued by the National Hardwood Lumber Association, 5) Eozt Van
Buren Street, Chicago, Illinois. Amonf- the -oods incluri:. rrc o-k, maplo,


R129g


-9-






ash, elm, basswood, beech, birch, hickory, sweetgum, yellowpoplar, cotton-
7'ood, pecan, locust, tupelo. Also included in the rules issued by this
association is cypress.


Lumber Prices


Information on current lumber prices is publisnhed in various trade
journals. Among such are the following: American L-.rmb'-rm-n, Commercial
Bulletin, 1ew York Lumber Trade Journal, Southern Lumberman, 7nd West Coast
Lumberman. Published price information is chiefly valuabl' for comparison
of species. Prices are quoted with reference to specific markets so that
they are not reliable indexes of what the costs might be delivered to cer-
tain points distant from the price basing centers.

There are no published prices for dimension or re'o:W-.zut stock.


Seasoning


Wood used in the manufacture of farm machinery and equipment will
not give its best service unless it has been properly dried before it is
installed. Tests made by the Forest Products Laboratory sho'i that wood for
outdoor use should be dried to moisture contents of 7 to 14 percent based
on oven-dry eight. For use in the dry southwestern state the averA-e
should bn 9 percent and the variation in moisture content not greater than
7 to 12 percent. In:the remainder of the United States th, moisture content
should be about 12 percent and variation not more than between 9 and 14 per-
cent. Wood dried to these moisture contents will give satisfactory service
in most items of fTari machinery and equipment. It is especially recomIended,
however, that wood wheel and wagon box parts be thoroughly dried so there
will be no further shrinkage after assembly.


Moisture Content Tests

The moisture content of wood can be determined by n' one of sev-
eral methods, the most common of which ari oven-dryin- tfsts and instan-
taneous electrical moisture meters. The oven-di`,inf method is the more
accurate but is slow, while the electrical method -wivs quick results, but
is not accurate under all conditions.

In the oven-drying method, samples 3/4 to 1 inch lone in the direc-
tion of the grain are sawed from representative boards or pi-eces. These
samples should be cut at least 1 foot fro:: the end of the i.oce to avoid
the effects of drying from the ends, and should be free from knots and
other defects,

Cutting samples for oven-drying tests.--Each sarmle is weighed
immediately after cutting, placed in an oven heated to 2120 to 221 F.,
and, dried for g to 24 hours or until no more weight is lost. Scales or


T1298


-9-





balances with a capacity of about 200 grams and sensitive to 0.1 gram should
be used. The following example illustrates how moisture content is computed:
(Original weight) (Oven-dry weight)
125 grams .inus 105 grams 20 = 0.19 or 19 percent
105 grams 105
(Oven-dry weight)
Several types of portable electrical moisture meters are available
with which the moisture content of wood can be determined directly. In rs-
ing these instruments sharp, short, metallic terminals are imbeddeO in the
wood, and the electrical resistance read from the instrument in termi, of
moisture content. The rpng-e of most of these instruments is about 7 to 24
percent. Electrical moisture meters measure the moisture content of the
wettest wood with which the terminals come into contact. They are usually "
designed for use on lumber or wood parts which arc about 1 inch thick and
may not be accurate for thicker material -- which is normally wetter in the
interior than on the surface. In wood thicker than 1 inch the moisture 'ra-
dient may be estimated by using electrodes driven to different depths. Tolse
instruments will also be inaccurate in testing pieces which have for an"
reason been recently wet on the surface.


Air Seasoning

Thoroughly air-dried wood will reach a moisture.content of 12 to 15
percent, and is, therefore, usually at or above the 'mruaximum :hich should be
used for farm equipment parts. For this reason it is important that mnnu-
facturers who have no kiln-drying facilities air dry their lumber to the
lowest practicable moisture condition.

The methods of piling lumber for air seasoning have boen studied
in considerable detail, end considerable information is available covering,
the methods Pnd practices which should be followed in order to get the best
results. Following is a summary of these practices as concern the most
important damav'es to lumber during air seasoning.

Lumber Piling Practices Which Will Reduce Seasoning Damage
To reduce the occurrence of:

Chec'-ing : Warping Blue stain and decay

Lower the founda-:Use :Raise the foundations. )
tions. Decrease :stickers,:Increase the spacing be- )
the spacing be- :of uni- : tween boards and between )
tween boards and :form : piles. )
between piles. thickness:Provide one control flared )Stain or Jpca7
Use thinner, nar-:properly : chimney, or a 7eo'ies of ) occurring throufh-
rower stickers. :aligned : narrow chim.r.ys. .) o't thc nile.
Place the end :and sup- :Use thicker, narrower )
stickers so that :ported, : stickers. )
they project be- :and suf- :Build narrower piles. )
yond the bonds of :ficient ---------------------------------------------
the pile. in number:Provide short chimneys (1/3)Stain or dcn' oc-
Use end coatings.: : or 1/2 height of pile). ) curring iu the low-
:Use thicker stickers in the) er part of the oilo
: : lower part of the pile. ) only. _____
R129S -10-






Kiln Drying

Advances in dry kiln construction, installation, and operation have
been rapid, especially durin- the past 15 or 20 years. Most of the old-
model kilns do not have the volume or quality of production which is possible
in the newer units, in which tLperature and relative humidity can bo con-
trolled more closely and in which the rate of circulation has been increased
rreatlyr.

As in the case of air seasoning, detailed studies and research hrive
been conducted covering many important phases of dry kiln construction,
operation, and maintenance. The following is a summary of these prractices
as they apply to some of the most important items of drm.-. to 7ood, during
kiln drying:

Practices Which Will Reduce Kiln Drying Damage
To reduce the occurrence of:

*
Surface checking : End checking : Wcarping Honeycomb

Increase the rate :Pile more :Pile more care- :Prevent surface check-
of circulation. : carefully. fully, using : ing ond minimize case-
Use higher humid- :Use end coat- : more stickers. : hardening by using
ities at the be- ings. :Increase rate of : milder drying con-
ginning of run. : circulation : ditiors.
: through pile. :Get uniform circula-
:Relieve casehard-: tion throughout pile.
ening.
:Use heavy weights:
on top of pile.



E:-H Coatings

Since rood dries faster from the end grain then from the side <,rnin
some kinds of vood, especially in thick sizes, may check and split during.
air seasoning. For this reason it is often a>visable to use a moisture-
resistant end coating for air seasonin- or kiln drying.

Coatings ordinarily used are of two classes. Those inr the firnt
class are liquid at ordinary air temperatures and can be riolied cold.
Those in the second class are solid at ordinary tem',rrtures, nnd nust be
heated before being applied. The hot or cold coatings are Pffective for
drying temperatures up to 140 F., but for trrp-rtures bhtveen l140, and
1700 hot coatings should be used.

TI:.1 two best cold coatin,-s developed are harden'ed loss oil thick-
ened with barytes and magnesium silicate (very cheap) nnJ hifh-'ra'e Dpar
varnish and barytes (expensive).

The gloss oil is made up as folloi-s: The oil should be of a thick
grade -,:.d- up (by the paint manufacturer) of about 8 parts by weight of
quick lim3, 100 parts rosin, and 57.5 ..ar:.s mineral spirit. To 100 parts
H129g -11-






of the gloss oil add 25 parts barytes and 25 parts of magnesium silicote.
One or two parts of lamnpblack- can be added if a black coating is desired.
This coating can be made by any paint manufacturer, or it can he nmixod( by
the user as needed, in case the proper grade of gloss oil] is obtain<1.
Some gloss oils have little moisture resistance, and it is necessary,
therefore, that the coating be made up according to the ,bove fori:ulia.

Paraffin is a satisfactory end coating for use on materiel -rhich
is to be air seasoned, but its melting point is too low for use on stock
to be kiln dried.

The most effective method of applying hot coatings is to dip the
ends of the stock about 1/2 inch into the coatings. For this reason it is
difficult to apply these coatings to large-size material. Hot coatin;-s are
effective in the following order:

213 co-l-tar pitch ............................... cheapa)
2540 coal-tar pitch............................... (c p)
Rosin and lampblack (100 parts of rosin to 7 parts
of lamipblack)................................... .(moderate co;t)


Preservative Treatment


The use of wood. in farm machinery nmd equipment involves only rel-
atively few parts and items in which preservative treatment or th( usV of
naturally durable -oods is necessary. The;e parts are, for )xv-Thl:

Skids -- for engines, shelters, self-feeders, ho- trar s,
and other wood-mounted items

Tanks and silos -- for water and fodder storage

Foundations and frames -- the lower parts of which norm'Ill7
are'in contact with the ground
N
The need for decay resistance in a wood part "-ill be determined b77
use conditions. Resistance to rot is necessary in parts which l. rr to be in
direct contact with the ground and in parts viwhich otherwise )ro used inder
conditions which result in the accumulation of mioisture'. For u -iInder these
conditions it is recommended that the wood parts concerned be tented by one
of the following methods:

1. Pressure treatments -- using preservatives such as coal-tnr creo-
sote or pentachlorronenol solutions (for parts which are not to be pointed),
or zinc chloride (for parts which are to be painted). Pressure treatment is
the most effective, and most expensive, treating method, and neeA ised
only under conditions of high decay hazard.

2. Hot and cold bath treatments are less expensive than the pres-
sure treatments, and can be accomplished at the manufacturing -,uIant. TheIse
are the most effective of the nonpressure treatments, end are s'ita'bi for Oe-
cay protection under all but the most severe service conditions.
R1299 -12-





3. Steeping treatments are generally less effective than the hot
and cold bath methods. LMercuric chloride has been commor.P used, but zinc
chloride, sodium fluoride, and other water-soluble pres-rvatives can be
employed. Soaking dry wood in untreated solutions of pentachilorphenol gives
some protection with practically any wood and may give excellent results
-ith woods that are easy to treat.

4. Dippin- treatrc-nts using hot preservatives, such a- the cre-
osotes or pentachlorphenol solutions, have only limited effectiveness under
severe service conditions.
5. Pruhir nd spraying treatnents that are sometimes use. with
preservative oils, are the least effective methods of protecting wood from
doc ay.

Detailed information on these treatments and the chemicals us-.l is
available from the Forest Products Laboratory.


Bent Wood Equipment Parts


Curved members of wood are produced by band sa-inc or by b'nd.ng.
B3ud-s.s'ed parts are more subject to splitting. and breikin,: because the
direction of the grain of the wood does not follow the curvture of the
piece. Thin stock bend more readily than thick stock; therefore, bent.
single pieces are sometimes glued together to produce a part of the re-
quired thickness.

In making single-piece bent members the stock must be softened,
and heated usually -'Tith steam or hot water, to permit the required defor-
mnItion. Straight-grained material free from defects is essential for bends
that involve extreme deformations.

Hard-'oois, especially elms, ashes, hickories, withstand extreme
bending better than softwoods -- pines, firs, hemlocks, etc. The oaki;,
beech, birches, maples, and gums can be successfully bent.

Wood that has been steam-bent should preferably be dri'd on forms
or otherwise held to desired shape until at about the moisture content it
will have in service is reached.

An extremely important factor in bendin 7 wood successfullW is the
design of the mechanical apparatus used for rp-lyinp pressure. :ny comrmer-
cial losses in bendinr can be preventcO thro".rK th' use 1f rroor Oqui-.'ent.
The use of adequate straps on the tension sit!>, of the bend and proper ores-
sure t:-k,-r devises for the ends of the Tiece.. are features commonly over-
looked. This is a clear-cut mechanical problem, not one that has to be loft
to chance and the so-celled vagaries of wood.

7Tnod loses some of its strength in bending, the amount of loss l.e-
peniliic- upon the svfrity of the bend. Trade directories include thc. names
of concerns that specialize in wood bending. In some cases it m-ir be advon-
taOeous to investigate the capacities of such plants for undertalcin, s-ecial
bonclir. jobs.
H129 _-13-







Wood-damagin2 Insects


Implement stock in dry storage is sometimes badly danmad by te
larvae of the pow-der-post beetle, so it is well to be on the lookout for
this destructive insect. Evidence of its work is the accumulation of a fine
powder coming from holes 1/16 to 1/12 inch in diameter. When then-e holos
are numerous they weaken the wood to a considerable deree.

Woods preferred by these insects are ash, hickory, ard ok; other
harrd'.-oods, including maple, elm, and poplar, are affecteO to a lesser ex-
tent. Only seasoned sap-ood of these roods is dmaged; therefore, wood
that has been in dry storage for a considerable period of timi noeds close
watching and preferably old stock should be used before newly-pil:2c0 material.

Since the eggs of thn insect are laid in the open pore.s of the wood
any finish, such as paint, varnish, or boiled linseed oil, will effectivelyr
prevent infection. If infestation is already present, sterilization may be
accomplished by steaming at not less than 130 F. treatment in a dry kiln
at lO for 1-1/2 hours is effective for inch lumber, and a proportionately
lon-er time for thicker lumber.

Where practical the infestation ia,:. be halted by a thorog.,'h appli-
cation of kerosene or a mixture of three parts kerosene and one part coal-
tar creosote.

The following points are set down to sum up this discussion:

1. Commonly affected woods are ash, oak, hickory.

2. Heartwood is not affected.

3. Only seasoned sapwood is affected.

4. Keep old stock moving.

5. If practical, paint or finish parts to be stored.

6. If practical, sterilize wood with steam or dryr kiln trentmant.

7. Where practical, halt infestation with ;-erosene or k ro '-
coal-tar creosote mixture.


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UNIVERSITY OF FLORIDA

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