|Table of Contents|
Front Cover 1
Front Cover 2
Board drop hammers and commercial laundry machines
U. S. Department of Agriculture, Forest Service h
FOREST PRODUCTS LABORATORY
In cooperation with the University of
Wisc .G\O' 0
K .) -p/t
THE USE OF WOOD IN AMERICAN MACHINERY
By GEORGE C. MORBECK
July, August, 1936
/ 'F /
Digitized by the Internet Archive
THE USE OF 7;OD IN AMERICAN MA:LHII:RYi
GOR(G C. IOCRETCr:
This brief description of how and where wood is used for
machine parts was prompted by a request from C. I. B. (International
Committee on Wood), an European agency interested in wood utilization-
The information gathered with respect to American industries should also
be of interest to American wood users and to the woodworking and lumber
industries in general. In addition it contributes to a subject of
current economic interest, namely, the future trend in wood consumption.
Smie c-: the data presented are chiefly of historical interest,
since in certain manufacturing industries wood has all but disappeared
in current types of machinery. On the other hand, in some machinery
lines wood parts have withstood the assaults of encroaching materials
to a remarkable degree. The employment of wood for parts of machines
of current manufacture is dictated largely by service requirements and
cost. There are r aching parts for which wood is apparently indispensable.
For nany other p. rs w.%d is giving satisfactory service at less cost
than any material that tight be substituted for it.
Machinery, for the purpose of this study, is limited to actual
operating units in a fairly restricted sense, and does not include other
items equally necessary to production, which may be termed accessories
or equipment. For example, a paper machine is a highly developed piece
of operating machinery. Tanks, vats, and chests are accessories required
in papermaking. In most industries more wood is used in accessories
and equipment than in machine parts. No attempt has beeoon made, however,
to cover the equipment phase of wood use, except in the pulp and paper
industry, where it was found very difficult at times to make a clear-cut
distinction between machinery and equipment.
All industries having machinery that employs wood parts
obviously cannot be covered in this brief survey. Many industries not
considered probably use more wvood for machine parts than some of those
covered. The lines of machinery selected for consideration are fairly
representative of machinery in general and should afford a good insight
into the extent and kinds of wood used for machine parts.
The use of wood in agricultural implements is steadily declin-
ing. Apparently it must be proved that wood members in farm equipment
are the equal of or superior to members made of other materials, and
where equality of service exists it must be shcwn that wood can be
installed at a lower cost, to make its uso possible.
A study of the current use of wood in agricultural machin.r',
reveals that handles of wood are holdir- up very well. All typos of
walkin. plows, hand corn and cotton drills, and hand and hor23-dra.m
cultivators are equipped almost universally with wood handles. The
species used are chiefly oak and ash. Wood handles have advantages over
other materials in that they are easily fabricated, can be readily
replaced, and are low in cost. Wood handles also afford a comfortable
grip in service regardless of prevailing temperatures, which is an
important factor contributing to their wide use.
Plow beans of wood are apparently on the way out, except for
special equipment. Heavy duty plows are made with oak beams, heavily
reinforced with steel. Standard plows arc practically all equipped with
steel beams. Substitution of steel for wood in standard plows was
largely the result of production difficulties, three of which stand out
prominently: high loss of stock from warping and checking daring season-
ing, difficulty of obtaining a regular and constant supply of beams, and
difficulty of adapting beams to the various forms required.
Hitch parts in earlier days were wholly of wood, chiefly oak
and hickory. Today practically all horse-drawn farm machines are
equipped or can be su
Grain drills have stood up well against changes in materials
of construction. The old standard wood seed box and Tood wheels can still
be had in drills, but the all-steel drill is rapidly replacing the
composite type. Implements for preparing soil for crops, in which wood
was formerly used in large amounts, now contain practically no wood.
Some items still have wood platforms, generally hardwood, for weighting
with roc'.- or iron. Wood bar harrows are occasionally made and disc
har:rows have har.d maple bushings.
Harvesting and threshing machin-rry likewise contain few wood
parts. Reel bars and arms, chiefly of yellow pine; pitmans of hickory
or hard maple; conveyor slats of oak, hard maple, or similar hardwoods;
occasional elevators, divider boards, gatherer boards, and bundle con-
veyors, all chiefly of southern yellow pine, constitute the bulk of the
few remraining items of wood used in the construction of harvesting and
A bright spot in the agricultural machinery field is the exten-
sive use of wood in haying tools. Hay loaders have conveyor slats of
maple, oak, or similar hardwoods, and conveyor guides of yellow pine or
Dou-laz fir. Sweep rakes are almost wholly of wood. The long, heavy,
square tooth and the framework of the machine arc chiefly southern yellow
pine. Hay stackers are also principally wood, most of which is southern
The substitution of metal for wood parts of farm machinery,
apparently largely a matter of production, often has little to do with
the utility of the material displaced.
Flour Milling M.achinery
Probably no other important industry employs a higher propor-
tion of wood in the construction of machinery than flour milling. Many
of the machines are almost wholly of wood. Roller mills (grinding
machines) are the one notable exception. Flour milling machines are
of sturdy construction. Conditions of service of these machines are
conducive to long life and replacement is largely due to remodelling of
plant or obsolescence.
The principal items of flour millirv: machinery are roller
mills, sifters, purifiers, bran dusters, and rolls. IAalt cleaning and
crushing machinry- is a closely allied item in which considerable wood
Wood used in the construction of flour milling machinery is
rather highly standardized as to species and quality of material. Some
of the machines are subjected to a continuous oscillating movement in
use. All must withstand considerable vibration under operating condi-
tions. The framework o' the various machines must therefore be strong
and alAe to withstand instantt wracking in service. Wood used in housing
machines should be light in weight, and have little "come and go" with
normal changes in moisture content thus insuring tight joints at all
times. Also the wood should remain in place well with a minimum tend-
ency to warp.
Hard maple is preferred for the heavy framework of all flour
mill machines, When hard mcple is not available yellow birch is used
for machine frames. Posts, top and bottom members, and other frame
parts in the larger sizes are approximately 3 by 5 inches in cross sec-
tion. White ash is extensively used for bracing, door frames, and
collector sides. Northern white pine is the standard species for housing,
sheathing, conveyors, and similar items where light weight and tightness
of construction are essential. Douglas fir is occasionally used for
conveyor sides, replacing white pine. Sieve frames of flour sifters are
basswood; the cross bars are hard maple. Flour sifters are supported by
a series of rock elm rod assemblies. There are usually eight rods in a
group and two sets of rods are required for each sifter.
The encroachment of other materials in flour milling machines
has in general not been extensive. Roller mills are of metal except
for the housing, which may be either of wood or metal. Few roller mills
with metal housing are sold because of their additional cost. Sieves of
flour sifters are obtainable with aluminum frames, also at added cost.
The interior moving parts of rolls &re sometimes of metal, replacing
wood. Bran dusters can be had in an all-metal construction. Malt
cleanin- and crushing units are of all-wood and all-steel construction.
The increased use of steel in the last mentioned two items is of fairly
In the textile industry the heavy framework of looms is grad-
ually being replaced by steel angle irons. Less wood and more steel
is beinhr iised in the fabrication of laywoods. Canvas picker stick con-
nectors are rerlacirng to some extent hard maple and ash. In some paper-
less beams, low carbon steel is replacing Sitka spruce. Pressed steel
sheaves are sometimes installed in the larger looms in place of the hard
maple sheaves. In general, however, wood is holding up well in the con-
struction of textile machinery.
,7ood in the textile industry is employed for parts where the
requirements are usually very exacting. One of the largest loom works
reports that in the construction of a wide variety of looms, seven
species, namely ash, hard maple, birch, hickory, applewood, yellow
poplar, and Sitka spruce, comprise more than 99 percent of the total
wood used for machine parts.
The most important requisite of any wood used for loom parts is
its ability to remain straight and true in service. Also of utmost
importance is freedom faom checking in use. These requirements can be
satisfied by selecting straight-grained stock and by proper seasoning.
Where large sizes are needed the parts are commonly built up in order
to avoid warping and checking in service. In addition to the general
properties just named, there are several types of uses of wood in looms
that have individual requirements. These requirements are given in the
Beams and Rolls
Beams in this category are cores of large spools upon which warp
is wound. The warp is delivered to the loom from the "spool" and only
the first winding comes in contact with the wood. Sitka spruce is used
exclusively by one large firm for beams. Yellow poplar is employed to
some extent by other manufacturers for th,-t purpose. Beams are either
solid, in sectors, or built up. Sitka spruce and yellow poplar have
sufficient strength for beam use, are light in weight, and machine
well with a minimum of splintering, all of which contribute to their
high serviceability for beams.
Rolls are largely guides for the warp and cloth. Aside from
stiffness and strength required of a wood for rolls, it must be hard,
uniform textured, nonsplinterinC and wear-resisting. A smooth surface
is essential at all times. The wearing surface of this type of roll
is exclusively hard maple. Small rolls are solid; lar-e rolls are
built up with yellow poplar ends and Sitka spruce centers. Cloth
guide-rolls of certain types are Sitka spruce, particularly the large
covered rolls of built-up material. Rolls which receive the finished
product are also largely of spruce.
Frameowvork, Connectors, and Beamrs for
Attachmunent of Working Parts
The added requirements for most of the *,;ood parts in framework,
connectors, and attachment beams are high strength and hardness, -,ood
wearing qualities, and high shock resistance. Apparently white ash
satisfies these requirements very well, since, except for a small amount
of hard maple, it is the wood most used for the purpose.
Shuttle Racks, Runs, and Shuttle Tops
Woc'd for shuttle racks, runs, and shuttle tops must be hard
and wear resisting, and must remain smooth in service. By far the most
extensively used wood for such purposes is apple. Dogwood is used in
smaller amounts. For the most exacting parts Turkish and West Indian
boxwood are employed.
Picker Sticks and. Connectors
The requirements of a wood for picker sticks are most exacting.
The ideal wood should be light in weight, very strong, tough, and resilient.
Hickory conforms most nearly to the requirements for picker sticks, and
hence is universally used for that purpose. Picker stick connectors are
of hard maple and ash because of their high strength and general service-
Sheaves, Bearings, and Similar Items
Sheaves, bearings, and similar items are of hard maple. The
hardness and ability of maple to wear smooth in service adapts it well to
such uses. When employed for bearings and bushings, maple is made self-
lubricating byitrpregnating with oil. The extensive use of oilles bearings
in the textile industry is due to the fact that they reduce the hazard
of soiling cloth-making materials.
Dobby Bars and Cylinders
Bars and cylinders of dobby looms are constructed chiefly
of birch and hard maple. Both uses require a hard, strong wood that
wears smooth in service and is not splintery in boringJ. Birch,according
to one large manufacturer,splinters less than hard maple and is there-
Dairy Products Machinery
Wood in machinery for making dairy products is confined largely
to churns, cheese vats, and cheese presses. Smaller items, such as hand
butter workers, butter printer boxes, ladles, and packers, are also chiefly
The requirements of wood in dairy products machinery are quite
exacting. Of first importance is the matter of freedom from inTparting
objectionable odor or taste to the manufactured product. The wood should
also be strcnE., stable in service, and have low shrinking and swelling
in use. This requirement is attained by employing only edge-grained
material. High decay resistance is also essential. Other factors being
equal, the cost of lumber for items requiring stock of large sizes limits
to some extent the species used
Commercial butter churns are essentially closed tanks of various
sizes to suit individual requirements. T'.e cylinders and heads of churns
made by one of the largest manufacturers of commercial dairy products
equipment are of clear heart vertical grain Douglas fir. The staves are
of various thicknesses, ranging usually from 1-1/2 to 2 inches when
finished. Douglas fir stave stock is purchased rough, and is surfaced,
tongue and grooved, and run to the proper curvature in one operation. The
width of staves is uniform for churns of all sizes, nominally 4 inches.
Churn heads are of stocl 10 to 12 inches wide. Churn shelves are also
of clear heart vertical grain Douglas fir. Butter rolls are redwood.
Each roll is made from a 7 by 7-inch or a 10 by 10-inch redwood timber.
The stock is practically green when used. Churn doors are of 1-inch
redwood, Doujlas fir, or cypress, usually in one piece, up to l1 inches
in width. Vertical grain stock is preferred.
Cheese vat frames are of vertical grain Douglas fir of the
same quality as for churns. The stock is wide and occasionally in the
larger vats 2-1/2 inches thick. Douglas fir is also used in large
sizes for cheese press frames. Red-ood is occasionally used for cheese
vats and presses on special order.
Hand butter workers are hard maple. Butter print boxes are
heart yellow poplar. The sides are of one piece l1 inches wide. Ladles
and packers are usually hard maple.
There has been no substitution of other materials for wood
in commercial churns. The wood used, however, has changed with time,
due to difficulties in obtaining suitable material or to high cost.
Early churns were commonly of yellow poplar and cypress with yellow
poplar rolls. Hard maple was also used for rolls. Douglas fir and red-
wood, the species currently used for cylinders, shelves, and rolls, are
apparently satisfactory in use and are readily available in the sizes,
types, and grades required.
Cheese vats and presses can be had of all-metal construction.
The use of metal vats is incrensin,-.
Board Drop Hame.iers
Board drop hammers are in common use in the production of
certain types of forgings, The essentials of such equipment are the
ram to which the board is attached.and the rolls which, pressing against
the board, lift the ram to the height desired for dropping. CI.:rps are
sometimes used for grippin:- the board instead of rolls. Hammer boards
are invariably of hard maple. Many other species have been tried, but
none seems to be as satisfactory as maple. Boards range in t'.ickn..3s
from 1-1/4 to 1-3/4 inches, in width from 2-1/2 to 16 inches, and in
length probably from 6 to 12 feet. The most commonly used finished board
sizes appear to be 1-9/32 to 1-1/2 inches thick, 5 to 6 inches wide, and
g-1/2 feet long. Boards over 8 inches wide are built up of two or more
Hammer boards are subjected to hard usage. The life of a board
in service may be only a few minutes if serious hidden defects are present,
or 300 or more operating hours under favorable operating conditions. The
average life of hammer boards in service is probably somewhere between 50
and 100 operating hours.
Hard maple for hanmmner boards must be straight grained, flat,
sound, and dense. The wood must also be thoroughly seasoned. Failure
of the wood in hammer boards is due largely to crushing of the board
where gripped by clamps or where the rolls start in raising the ram.
The shock sustained by the board at moment of impact is likely responsible
for failures through splitting. Boards seldom if ever fail due to the
load being lifted.
The volume of maple used for hammer boards cannot readily be
estimated. Manufacturers of hammers furnish some boards, but the bulk
of the stock is supplied by local dealers. There is at present no sub-
stitute material replacing hard maple for hammer boards as far as can be
Commercial Laundry Machines
Wood in laundry machinery is confined chiefly to washers. P..:
conditions which have to be met in a material for washers involve l.r,-elh
corrosion in contact with chemicals employed in waFhinf processes, and
contamination or stainirng of the clothes. Wood resists chemical action
and contains no substances injurious to fabrics.
Commercial washers consist essentially of two parts, the shell
or stationary tub, and the interior cylinder. The shell in the best
grades of washers usually has heart cypress sta-es and heads. Other
softwoods having high decay resistance are probably also suitable for
shells in the better grades of wai;hcrs. Lo'.er priced washers have tubs
of Douglas fir. Both staves and heads are usually of 2-inch material.
Heart cypress and Douglas fir have sufficient strength for tub use,
hold fastenings well, resist action of chemicals, and arc resistant to
Washer cylinders are commonly of heart longleaf pine. This
species is preferred for cylinder parts because of its high resistance
to wear under action of chemicals employed in washing. Cylinders of
lonleaf pine and similar woods are strong and rigid and hold up well
in service. In the better grades of washers, heads of cylinders are of
3-inch stock. Staves are generally 2 inches thick.
Hard maple lifting ribs are the rule. Hard maple has the high
wearing and nonsplintering qualities required in a wood for rib use.
Doors aind door ribs are commonly of the same species as the staves.
Current types of commercial washers show some replacement of
wood by other materials. Washers with brass cylinder partitions and
doors and with monel metal liftingE ribs are available in the higher
priced lines. Galvanized iron doors are replacing wood doors in the
cheaper grades of product.
Pulp and Paper Machinery
The use of wood in the construction of pulp and paper plants
is declining with each new mill installation. Wood when employed is
confined to structural units, such as conveyors, chip bins, and other
component parts of the building and in more or less nonoperating items,
which to differentiate them from operating machinery, may be classed
as equipment. In this category are storage tanks, vats, screen boxes,
bins, pipes, tubs, and chests.
It is obviously difficult in many cases to separate equipment
from the machinery it serves. Since the bulk of wood used in pulp and
paper manufacturing processes is employed in items defined as ciuipmynt,
it may be well to cover briefly the use of wood in that classification.
Species used for containers of liquids and pulp mixtures are
the regular tank and vat woods, principally cypress, redwood, Douglas fir,
and southern yellow pine, includin- longleaf, generally of tmank grade.
From the standpoint of service other species can be substituted in some
types of tar-:s and vats; the foregoing woods, however, are readily avail-
able in stock sizes, which is a considerable advantage when purchasing
tank l-j'-bor. The species employed for tank, vat, tub, or chest depends
on the type of use to which the container is Put. Containers of southern
yellow pine and Douglas fir are commonly employed for storing chemicals
in which chemical action on the wood is the principal cause of failure.
Stock ready for the paper mill, because of frequent washings is free of
injurious chemicals. Deterioration of various wood containers used in
the latter stages of papermakinu is therefore due largely to decay.
Where lon. life is desired of such containers, heart cypress is commonly
employed in their construction. Heart redwood is probably equally suit-
able. Quite commonly,however, little attention is paid to species for
tank and vat construction as between the various species mentioned.
Douglas fir and southern yellow pine are less expensive than redwood
and cypress, and that consideration is sometimes the determining factor.
Pipes carrying stock or water are often of wood. Douglas fir
and redv';.od are commonly used for stave pipe. Wood pipe is preferred
by many to pipe of other materials because of its low t.'ndency to "slime,"
and its relatively low cost.
WTood in pulp and paper equipment is rapidly being displaced by
metal, concrete, rubber, and other materials in new installations and
also often in replacements. Tanks, vats, sieve boxes, and similar items
are principally affected. These items will probably continue to have
certain wood parts, such as agitation arms, which are of hardwood --
chiefly hard maple, oak, and ash; cylinder fins for elevating pulps in
deckers; some wood couch rolls in wet machines of a variety of species,
such as hard maple, black gum, cypress, yellow poplar, and yellow pine;
and filler strips between beater bars, chiefly of hard maple and oak.
The total incidental wood employed in modern equipment for making paper
is small, with little apparent chance of future increase.
A still smaller volume of wood is used in pulp and papermaking
machines, especially in machinery of the latest designs. The machine
that probably uses the largest amount of wood is the "jordan," which
consists essentially of an outer shell with a cone-shaped plug. The
filler strips between the metal bars of both shell and plug are hardwood,
chiefly red oak and sugar maple.
"Save-alls" at the front end of paper machines are often of
wood construction. Cypress or some other decay-resistant softwood of
tank stock grade is commonly employed for this item. The "shock ab-
sorber" attached to a shaker is of wood, usually hard maple. Suction
box covers are hard maple, or some other long, even-wearing species.
Recent paper machine installations have suction box covers of bakelite.
Press rolls of wood are obsolete. Felt rolls are of yellow
poplar, basswood, or some other soft fine-textured species. NeW materials
for rolls include rubber metal, various compositions, and granite.
Wood Bearings and Bushings
Bearings and bushings of wood have been used in machine con-
struction for many years. Although developments in machine design and
materials have eliminated wood bearings in many types of equipment there
are still certain machines in which nothing appear, to be more suitable
for bearing use than woQd. Improvements in wood bearings and bushimngs,
in recent -rears have increased their usefulness considerably, and new
uses for those items have been developed. Practically all wood bearin-s
and buashings are now impregnated with lubricating material. The result
is a bearing that needs no oil during its useful life.
Qilless bearings and bushings have four principal uses for
which they are well adapted: for use in locations difficult of access;
where oil or other lubricants would soil or damage the product being
made; .1hei-e use conditions require occasional or frequent removal of
bearings; and where use of ordinary lubricants is impractical or im-
Probably the most general use of wood bearings and bushings
is in textile machinery, where danger of damage through soiling of
fabrics in the various processes of manufacture must be kept to a mini-
mum. For similar reasons wood bearings are extensively used in washin-
machines and wringers. Certain types of agricultural machinery are
equipped with wood bearings and bushings, notably disc harrois. When
worn out or broken in such use they can be quickly and cheaply replaced.
Wood bearings are employed in equipment that is constantly submerged in
water or other liquids in service. The use of ordinary lubricants under
such conditions is obviously impossible. In addition to the foregoing
uses, wood bearings and bushings are employed in flour machinery, shoe
machinery, paper folding and envelop equipment, cream separators, cash
carriers, vacuum cleaners, wells and pulps, scientific instruments,
hydraulic equipment, and stern bearings for ships. For the last named
two purposes lignum vitae is the principal wood used.
Practically all wood bearings and bushings are of hard maple.
The type of maple employed is usually northern grown clear sap stock.
For some uses beech is satisfactory.
There are a number of firms making wood bushings and bearings
though the market for them so far as number of outlets is concerned is
probably decreasing. In equipment that e;:ploys large quantities of wood
bushings and bearings, however, such as agricultural implements, textile
andla=undry machinery, the volume of wood consumed is still large and may
actually be increasing. Because of the nature of the industry no fi--ures
on consumption of wood for bearings and bushings are available.
The use of wood for pulleys probably dates from the first use
of belts or similar contrivances for transmitting power. With the pass-
ing years, improved design and better construction have combined to :ke'p
wood pulleys on the market in competition with those of metal and other
materials of which there are countless designs, kinds, and types. The
produ-action of wood pulleys has undoubtedly fallen off in recent years,
but one company of the half dozen or so that make wood pulleys still
uses almost half a million feet of lumber annually in their construction.
Wood pulleys are of two general types -- split pulleys and
solid pulleys. Split pulleys are of two identical parts each consisting
of a wood face made up of narrow glued members, and wood arms, one,
two, or more depending on the size or design of the pulley. The faces
or rims of wood pulleys are of basswood, sap gum, tupelo, and probably
other hardwood species in small amounts. Pulley arms are commonly of
hard maple and beech. Bushings are hard maple or sometimes beech.
Solid pulleys are commonly hard maple.
Manufacturers of wood pulleys assert that lightness of
weight and highstrength combined with high coefficient of friction
make it possible to run such pulleys safely at higher speeds than
pulleys of other types of construction.
The substitution of metal for wood
parts of agricultural Implements nas,
during the .em two decades, reduced the
volume of wood per unit of production
about one-half. One line of equipment
that has withstood the attack of steel
is haying tools. At the right is a
swing rake. Standard equipment of this
type is almost wholly of wood, chiefly
The grain drills also shown at the
right represent a class of equipment in
the construction of which wood is grad-
ually beiig replaced by metal. The
drill at the top has a wood seed box and
wood wheels. Below it Is a drill made
wholly of metal.
Below is a cut illustrating a 1914
model corn seller almost wholly of wood.
The 1932 model shown below it has changed
little in appearance, except that no wood
is used in its construction.
The old reliable oak plow beam has
been relegated to special item class.
Handles of walking plows, cultivators,
and similar items, however, are still
universally of wood, principally oak and
ZM 28368 F
I, -.- - - n g g.*
^ -a.TB~ir;^i~a^^^13~l.^ !Ka~L,
FLOUR -LLIrNO MACHINERY
Wood occupies a comanding position
as a material in the oonetruotion of all
types of machinery used In flour sanu-
faoture. A glance at the itema Illus-
trated indicated the extent to which wood
I employed. The heavy framework of all
the machines shown, except the roller
mill, in of clear hard maple. When the
proper type of maple in not readily
available, yellow birch is sometimes used
for frames. Smaller items of framework,
bracing, door stiles and rails, and hop-
per aides are ash. Housing and panels
are northern white pine. Flour sifters
are supported by a series of rock elm
rods one inch In diameter. Sifter
aoieve* have baasswood sides and cross
bars of hard maple.
Wood is especially well adapted for
flour milling machinery. The heavy wood
construction of the various machines re-
sists very well wracking and vibration
which are the primary causes of their de-
terioration. The clean, sanitary appear-
ance of wood Is an important asset In its
use In flour production.
Z 28366 F
Wood in an Important ltem in the construction of ...
loom and other textile machines. For many maohine
parts no satiasfaotory substitute for that material has
been found. Aside from the more general properties re-
quired of all wood employed, special requirements for
Individual machine parts are very exacting, and limit
the woods used to a very few species. Bard maple, yel-
low birch, hickory ash, applewood, yellow poplar, and
Sitka spruce comprise the bulk of wood used in looms.
The heavy wood framework in the loom shown below
is ash. Applewood is extensively used for circular
shuttle covers. The shuttle assembly is the piano
key-like arrangement running the length of the loom.
It is supported by ash beams. The beam uprights in the
background are also ash.
m t :111' I'U
cThe dobby loom above
has cylinders of hard ma-
ple. The bars passing
over the cylinders common-
ly are yellow birch. HBard
maple is also used for cyl-
At the right Is a typ-
ical silk loom. The rolls -
in the foreground are Sitka
spruce. The breast board 4
tray above the rolls in yel- --"
low poplar. Sheaves shown -M
at the top are hard maple.
The upright piece at the
lower right is the picker
stick which is Invariably
of hickory. The horizontal
picker stick connector is
Z M 28367 T
COMBRCIAL DAIRY MACHIXKRY
Wood retains ita supremaoy in mn ot the larger items
of maohinery In the dairy products Old. So other material
baa replaced wood in butter churns. The churn cylinder is
omnonly of olear edge-grain Douglas fir heartwood. Churn
door formerly of oyprsa are now largely edge-grain redwood.
Shelves attached to theo sida of the ohurn are usually Doug-
las fir. The large butter rolls are redwood. The illustra-
tion at the right seows the arrangement and extent of use of
wood In o orolJal churns.
Chooeese vatis and chaese preases Illustrated below are of
Douglas fir oenatruotion. All-ateel vats and press are
available at considerably greater oost.
a 10. itK .
i 1 20 19
16 17 20 21
The sides of the printer
are clear heart yellow poplar
in one piece.
IMPNF IENTS KPLOYED IN BUTTER KIHONG AND PACKIN
All of tibe Item Illustrated above are of olear hard ma-
pl*. Beeoh and birch are also used for ladles and paddles
employed in butter makIng.
ZM 28371 F
COMMERCIAL POWER WASHER
Wood continues to be used in considerable quanti-
ties In commercial laundry machines. The requirements
of construction materials are exacting. They must
stand up under the action of chemicals and impart noth-
ing that will damage clothes in the washing process.
NO low-priaeed material is as serviceable as wood in
pow r washrs. The shell of the wasaher shown above is
Doulas fir. Cypress is used for the more expensive
T2h interior cylinder and partitions are usually
of longleaf pine. Lifting ribs (not shown) are common-
ly hard maple.
BOARD 420P VlAXM
The type of fotsring halr
shown above employs a board for
lifting the ra into position
for the drop. Nothing but clear
straight-grai ed hard mapic 18
used for hammer boards*. High re-
sistance to aids Bmp oesSIon and
ability to absorb shook are es-
sential in a wood for that uSe.
The average life of homor boards
ranges from 50 to 100 working
PULP AND PAPER MACHINERY
Wood In machinery employed in the
paper industry is on the decrease. Tanks,
tubs, vats, sieves, and similar equipment
formerly almost wholly of wood are in new
installations often of steel concrete,
and other materials. There iS little wood
used in operating machinery. The illus-
tration at the left bhows wood bars in the
tapered plug of a *Jordan." The station-
ary shell in which the plug revolves is
similarly equipped with wood fillers. The
wood used is ohiefly oak.
The eccentric screen shown above and
similar screens have sides, ends, and
other parts of wood. The species employed
Is oemonly cypress. Other softwoods hav-
Ina# igh deeoy resistance are also suit-
able for careen use.
ZM 38370 F
BARIIS AID BUSHKIUGS
Wood bearings and buahings were quite
commonly employed in early factory and shop
equipment. For certain uses they have main-
tained themselves in spite of great advances
in engineering practise in recent years.
Practically all wood bearing and bushings
are Impregnated with oils, vaxes, paraffin,
or similar materials to provide oilless lu-
brication. Such lubrication is essential In
machines where ordinary lubricants will dam-
age goods in the process of manufacture, for
example, textile products. Wood buahings and
bearings are employed in locations difficult
of access. They are also extensively employed
in agricultural machinery, notably dise har-
rows, because of their easy replacement and
Wood bushings and bearings are chiefly
sapwood of hard maple. That wood is strong,
fine-textured, wears well, and impregnates
WOOD SPLIT PULErT
Pulleys of wood. were formerly in quite general use in
mills and factories and are still employed to a considerable
extent in some industries. The chief advantages claimed for
wood split pulleys are their lightness, ability to run at
high speeds without danger of breaking, and non-slipping
property. Wood pulleys can readily be made In any size and
type. They are also relatively inexpensive.
The face a of wood-split pulleys are buillt up of parallel
curved strips of basswood, map gum tupelo, and probably other
hardwoods. The arms
are of hard maple or
Wood pulleys are often I..--.
equipped with hard ma-
---- ^^-^M^^^ m|w
11 38 6 F: 1 J-n j. r .in*Jrl.J T I,.. r
WOOU BEAfl~ O~ C~L ~
$iih .. r,, 14 r ,
of bard maple.
ZU 88369 r
UNIVERSITY OF FLORIDA
II 11111111122 0li89289il
3 1262 08928 0209