PAES Flashcards
(210 cards)
1
Q
flexible machine element used to transmit motion and power between two shafts, the cross section of which is shaped roughly like a regular trapezoid outlined by the base, sides and top of the belt
A
V-belt
2
Q
wheel with one or more grooved rims used to transmit motion and power by means of one or more V-belts
A
V-pulley
3
Q
power transmission device, which consists of one or more V-belts, mounted on two or more
V-pulleys
A
V-belt drive
4
Q
the outside diameter of the pulley
A
Pulley diameter
5
Q
the diameter of the pulley, which coincides with the belt pitch
A
Pulley pitch diameter
6
Q
the region in the belt that keeps the same length when the belt is bent perpendicularly to its base
A
belt pitch
7
Q
the length of the belt at the level of its pitch
A
Belt length
8
Q
ratio of the angular velocities of the pulleys making no allowance for slip and creep
A
Speed ratio
9
Q
the linear speed of the belt at the level of the pulley pitch diameter
A
Belt speed
10
Q
belts used to transmit rotary motion and power between two shafts, which lie flat on the face
of its corresponding pulley
A
Flat belt
11
Q
wheel having flat or crowned face used to transmit motion and power by means of flat belts
A
Flat belt pulley
12
Q
power transmission device used to transmit power and motion between two shafts consisting of flat belts which ride in flat pulleys
A
Flat belt drive
13
Q
outside diameter of the pulley
A
pulley diameter
14
Q
stretched-out length of the belt
A
Belt length
15
Q
ratio of the angular velocities of the pulleys making no allowance for slip and creep
A
Speed rafio
16
Q
the linear speed of the belt calculated by multiplying the rpm and the diameter of the driver pulley and to the value of pi
A
Belt speed
17
Q
distance between adjacent joint members
A
Chain pitch
18
Q
the diameter of the pitch circle that passes through the centers of the link pins as the chain is wrapped on the sprocket
A
Pitch diameter
19
Q
the diameter of a circle tangent to the curve (called the seating curve) at the bottom of the
tooth gap
A
Bottom diameter
20
Q
for a sprocket with an odd number of teeth, it is the distance from the bottom of the tooth gap
to that of the nearest opposite tooth gap
A
Caliper diameter
21
Q
it is the diameter over the tips of the teeth
A
Outside diameter
22
Q
keys whose longitudinal sides are parallel with each other.
A
Parallel keys
23
Q
keys with a tapered longitudinal section.
A
Taper keys
24
Q
keys with a semi-circular cross-section.
A
Woodruff keys
25
a cylindrical gear whose tooth traces are straight lines parallel to the axis. Generally, it
transmits rotational motion and power between two axes
Spur gear
26
each of the projecting parts of a gear which are intended to ensure, by contact with the teeth of another gear, that one of the other gear turns the other
Gear tooth
27
the quotient of the pitch, expressed in millimeters, to the number π (or the quotient of the reference diameter, expressed in millimeters, to the number of teeth)
Module
28
the line of intersection of the pitch cylinder by a plane perpendicular to the axis of the gear
Pitch circle
29
the radial distance between the addendum circle and the pitch circle
Addendum
30
the diameter of the addendum circle
Addendum diameter
31
the diameter of the of the dedendum circle
Dedendum diameter
32
the radial distance between the addendum circle and the dedendum circle
Tooth depth
33
the length of the arc of the pitch circle between two consecutive corresponding profiles
Circular pitch
34
the width of the tooth measured along the circular
Tooth thickness
35
the space between teeth measured along the pitch circle
Tooth space
36
the tooth space minus the tooth thickness
Backlash
37
the width over the toothed part of a gear, measured along a straight line generator of the reference cylinder
Face width
38
The portion of the surface of a tooth lying between the tip surface and the root surface
Tooth plank
39
angle at the point where the profile cuts the pitch circle
Pressure angle
40
of an involute cylindrical gear, the "base circle" of the involutes forming the tooth profiles
Base circle
41
the line of intersection of a tooth flank with any defined surface cutting the reference surface
Tooth profile
42
the line of intersection of a flank with the reference surface
Tooth trace
43
a cylindrical gear of which every usable tooth profile is an arc of an involute to a circle
involute cylindrical gear
44
a plane curve described by a point on a straight line (the "generating line"), which rolls out without slip on the base circle
involute to a circle
45
Spur gear materials shall be of hot-rolled steel designation 1045 and 3140 with an ultimate
tensile strength of _____ and a Brinell Hardness Number of _______
respectively.
600 @724 MPA
| 215@205
46
cylindrical gear whose tooth traces are helices, it transmits rotational motion and power
between two parallel axes
helical gear
47
each of the projecting parts of a gear which is intended to ensure, by contact with the teeth of
another gear, that one gear turns the other
gear tooth
48
quotient of the circular pitch, expressed in millimeters, to the number π (or the quotient of the
diametral pitch, expressed in millimeters, to the number of teeth)
module
49
quotient of the normal circular pitch (expressed in millimeters)and the number π, where the
normal circular pitch is the product of the circular pitch and the cosine of the helix angle
normal module
50
line of intersection of the pitch cylinder by a plane perpendicular to the axis of the gear
pitch circle
51
radial distance between the addendum circle and the pitch circle
addendum
52
circle that bounds the outer ends of the teeth
addendum circle
53
radial distance between the dedendum circle and the pitch circle
dedendum
54
line of intersection of the dedendum cylinder by a plane perpendicular to the axis of the gear
dedendum circle
55
amount by which the dedendum in a given gear exceeds the addendum of its meshing gear
clearance
56
diameter of the pitch circle
pitch diameter
57
diameter of the addendum circle
addendum diameter
58
diameter of the of the dedendum circle
dedendum diameter
59
radial distance between the addendum circle and the dedendum circle
tooth depth
60
length of the arc of the pitch circle between two consecutive corresponding points of adjacent
teeth
circular pitch
61
length of the arc, living between the tooth traces of two consecutive corresponding flanks of a
cylindrical normal helix
normal circular pitch
62
width of the tooth measured along the circular pitch
tooth thickness
63
space between teeth measured along the pitch circle
tooth space
64
difference between the tooth space and the tooth thickness
backlash
65
width over the toothed part of a gear, measured along a straight line generator of the
reference cylinder
face width
66
portion of the surface of a tooth lying between the tip surface and the root surface
tooth flank
67
pressure angle at the point where the profile cuts the pitch circle
pressure angle
68
pressure angle at a point on a tooth trace
normal pressure angle
69
curve whose tangents are inclined at a constant angle to the axis of the cylinder
helix
70
in a cylinder on which helix is considered, a helix which is perpendicular to that helix
normal helix
71
acute angle between the tooth trace and the generator of any imaginary cylinder or cone
coaxial with a gear whose tooth trace is under consideration
helix angle
72
of an involute cylindrical gear, the "base circle" of the involutes forming the tooth profiles
base circle
73
the line of intersection of a tooth flank with any defined surface cutting the reference surface
tooth profile
74
the line of intersection of a flank with the reference surface
tooth trace
75
a cylindrical gear of which every usable tooth profile is an arc of an involute to a circle
involute cylindrical gear
76
a plane curve described by a point on a straight line (the "generating line"), which rolls out
without slip on the base circle
involute to a circle
77
gears which are used to transmit motion and power to shafts having intersecting axes
bevel gears
78
bevel gears whose teeth are straight but the sides are tapered so that they would intersect the
axis at a common point called the pitch cone apex if extended inward
straight bevel gears
79
bevel gears having equal numbers of driver and driven gear teeth and operate at axes with
right angles
miter gears
80
the quotient of the pitch, expressed in millimeters, to the number π (or the quotient of the
reference diameter, expressed in millimeters, to the number of teeth)
module
81
the length of the arc of the pitch circle between two consecutive corresponding profiles which
is measured at the large end of the tooth
circular pitch
82
the diameter of the pitch circle at the large end of the tooth
pitch diameter
83
the angle between the elements of the face cone and the pitch cone
addendum angle
84
the angle between the elements of the root cone and the pitch cone
dedendum angle
85
the length of teeth along the cone distance
facewidth
86
the distance from the end of the tooth to the pitch apex
cone distance
87
the angle formed between an element of the pitch cone and the bevel gear axis, it is the half
angle of the pitch cone
pitch angle
88
the angle between an element of the back cone and the plane of rotation
back angle
89
the angle of a cone whose elements are tangent to a sphere containing a trace of the pitch
circle
back cone
90
the distance along an element of the back cone from the apex to the pitch circle
back cone distance
91
for assembled bevel gears, the distance from the crossing point of the axes to the registering
surface, measured along the gear axis; ideally it should be identical to the apex to back
mounting distance
92
the diameter and/or plane of rotation surface which is used in locating the gear in the
application assembly
mounting surface
93
the sharp corner forming the outside diameter
crown
94
the distance from the crown to the rear of the gear
crown-to-back
95
the distance along the axis from apex of pitch cone to a locating registering surface on back
pitch apex to back
96
the angle formed between a tooth element and the axis of the bevel gear
root angle
97
the angle between meshing bevel gear axes: also, the sum of the two pitch angles
shaft angle
98
the between an element of the face cone and its axis (
face angle
99
the angle between an element of the front cone and a plane of rotation
front angle
100
the portion of the bevel gear tooth near the outer end
heel
101
the portion of the bevel gear tooth near the inner end
toe
102
load or force passing through the axis of rotation
radial load
103
L10
the number of revolutions or hours at a given constant speed that 90 percent of an apparently
identical group of bearings will complete or exceed before the first evidence of fatigue
develops
rated life
104
C
| the radial load that a ball bearing can withstand for one million revolutions of the inner ring
basic dynamic load rating
105
P
constant stationary radial load which, if applied to a bearing with rotating inner ring and
stationary outer ring, would give the same life as that which the bearing will attain under the
actual conditions of load and rotation
equivalent dynamic load
106
CO
the maximum radial load, which corresponds to a calculated contact stress at the center of the
most heavily, loaded rolling element/raceway contact of:
• 4,600 MPa for self-aligning ball; bearings;
• 4,200 MPa for all other ball bearings
• 4,000 MPa for all roller bearings
basic static load rating
107
PO
static radial load, if applied, which produces a maximum contact stress equal in magnitude to
the maximum contact stress in the actual condition of loading
equivalent static load
108
sleeve bearing
| a cylinder which surrounds the shaft and is filled with some form of fluid lubricant
journal bearing
109
the part of the rotating shaft , axle, roll or spindle that turns in a bearing
journal
110
a medium that supports the shaft preventing metal to metal contact
lubricant
111
a mechanical device designed specifically to hold, join, or maintain equilibrium of single or
multiple components
fastener
112
an externally threaded fastener designed for insertion through holes in assembled parts, and
normally tightened or released by torquing a nut
bolt
113
a block or sleeve having an internal thread designed to assemble with the external thread on a
bolt, screw, stud or other threaded part
nut
114
the designation used for the purpose of general identification; for external and internal
threaded fasteners nominal size usually is the basic major diameter of the thread; for
unthreaded fasteners, nominal size is usually the basic body diameter
nominal size
115
the length of a headed fastener is the distance from the intersection of the largest diameter of
the head with the bearing surface to the extreme end of the fastener, measured parallel to the
axis of the fastener
length of fastener
116
a thread which winds in a clockwise and receding direction from the starting end, when
viewed from that end
right-hand thread
117
a thread which winds in a counterclockwise and receding direction from the starting end,
when viewed from that end
left-hand thread
118
the specified load which the fastener must withstand without any indication of permanent
deformation after the load is released
proof load
119
```
the distance (in millimeters), measured parallel to the thread axis, between corresponding
points on adjacent thread forms in the same axial plane on the same side of the axis
```
pitch
120
for a straight thread, this is the diameter of the imaginary cylinder bounding the crest of an
external thread or the root of an internal thread
major diameter
121
for a straight thread, this diameter is the imaginary cylinder bounding the root of an external
thread or the crest of an internal thread
minor diameter
122
for a straight thread, this is the diameter of the imaginary cylinder whose surface passes
through the thread profiles in such a way to make the widths of the thread ridge and the
thread groove equal
pitch diameter
123
a headed pin of metal used for uniting two or more pieces by passing the shank through a
hole in each piece and then by beating or pressing down the plain end so as to make a second
head
rivet
124
the diameter of the shank
nominal diameter
125
the length from the underside of the head to the end of the shank
nominal length (rivets other than countersunk or raised countersunk rivets)
126
the distance from the periphery of the head to the end of the rivet measured parallel to the
axis of the rivet
nominal length (countersunk and raised countersunk head)
127
a type of riveted joint wherein the plates overlap each other and are held together by one or
more rows of rivets.
lap-joint
128
a type of riveted joint wherein the plates being joined are in the same plane and are joined by
means of a cover plate or butt strap which is riveted to both plates by one or more rows of
rivets
butt-joint
129
spacing between rivet centers
pitch
130
the distance from the edge of the plate to the centerline of the nearest row of rivets
margin
131
allowance in length of rivet in order to turn over or flatten the protruding end
clinch allowance
132
a mechanical device designed specifically to hold, join, or maintain equilibrium of single or
multiple components
fastener
133
an externally threaded fastener capable of being inserted into holes in assembled parts, of
mating with preformed internal thread or forming its own thread, and of being tightened or
released by torquing the head
screw
134
the designation used for the purpose of general identification; for external and internal
threaded fasteners nominal size usually is the basic major diameter of the thread; for
unthreaded fasteners, nominal size is usually the basic body diameter
nominal size
135
the length of a headed fastener is the distance from the intersection of the largest diameter of
the head with the bearing surface to the extreme end of the fastener, measured parallel to the axis of the fastener; the length of a headless fastener is the distance from one extreme end to
the other in a line parallel to the axis
length of fastener
136
a thread which winds in a clockwise and receding direction from the starting end, when
viewed from that end
right-hand thread
137
a thread which winds in a counterclockwise and receding direction from the starting end,
when viewed from that end
left-hand thread
138
```
the distance (in millimeters), measured parallel to the thread axis, between corresponding
points on adjacent thread forms in the same axial plane on the same side of the axis
```
pitch
139
the specified load which the fastener must withstand without any indication of permanent
deformation after the load is releasedthe specified load which the fastener must withstand without any indication of permanent
deformation after the load is released
proof load
140
for a straight thread, this is the diameter of the imaginary cylinder bounding the crest of an
external thread or the root of an internal thread
major diameter
141
for a straight thread, this diameter is the imaginary cylinder bounding the root of an external
thread or the crest of an internal thread
minor diameter
142
for a straight thread, this is the diameter of the imaginary cylinder whose surface passes
through the thread profiles in such a way to make the widths of the thread ridge and the
thread groove equal
pitch diameter
143
long evenly shaped piece of solid metal
bar
144
steel bar with lugs or protrusions called deformations
deformed bar
145
diameter equivalent to the diameter of a plain round bar having the same mass per meter
nominal diameter of deformed bar
146
long hollow cylinder of specified thickness whose nominal size is approximated by the inside
diameter
pipe
147
long hollow product of round or any other cross-section whose size is specified by the outside
dimensions
tube
148
rolled rectangular section of thickness over 0.15 mm up to 6.0 mm, with sheared, slit or sawn
edges
aluminium and aluminium alloy sheet
149
galvanized flat or corrugated metal product cut to the standard or specified length and has a
nominal base metal thickness ranging from 0.20 mm to 1.6 mm and a flat width of 760 mm to
1,220 mm
galvanized steel sheet
150
hot-rolled product supplied in cut lengths and produced by cutting from a coil rolled on a
continuous mill. It has a width of at least 600 mm and a nominal thickness of less than 3 mm.
The edges of the sheet may be either trimmed or untrimmed
hot-rolled steel sheet
151
product obtained by hot-dip coating steel sheet coils on a continuous aluminium/zinc coating
line to produce either coated coils or cut lengths
continuous hot-dip aluminium/zinc-coated steel sheet
152
rolled rectangular section of thickness greater than 6.0 mm with either sheared or sawn edges
aluminium and aluminium alloy plate
153
hot-rolled product supplied in cut lengths and produced by cutting from a coil rolled on a
continuous mill. It has a width of at least 600 mm and a nominal thickness of 3 mm
minimum. The edges of the sheet may be either trimmed or untrimmed
hot-rolled steel plate
154
flat sheet which is intended for general fabricating purposes where it is used as such or for
bending or moderate forming
galvanized commercial quality
155
sheet or coil which is intended for lock-seaming and other similar applications and have
better formability than commercial quality
galvanized lock-forming quality
156
sheet or coil which is intended for drawing or severe forming but excluding deep drawing
galvanized drawing quality
157
quotient of the load (when the specified permanent elongation occurs in a tensile test) divided
by the original cross-sectional area
proof stress
158
term applied to changes in physical and mechanical properties of low carbon steel that occur
with the passage of time and adversely affect formability
ageing
159
removal of oxygen which causes oxidation of steel
deoxidation
160
are designed to reduce coupling shack by slipping during the engagement
period. They also serve as safety devices by slipping when the torque exceeds their
maximum rating.
Friction clutches
161
produces its torque by virtue of the centrifugal force of weights pressing
against the driving or frictionally driven member.
Centrifugal clutch
162
consists of a frustum of a cone, so fitted to a shaft by means of a
feather key that it can be pushed into an opposite engaging surface rigidly attached to the
other shaft.
conical friction clutch
163
designed to transmit torque without slip, jaw clutches are the most
common. These are made with square jaws for driving in either directions, or spiral jaws for
unidirectional drive. These are used for slow-moving shafts, where sudden starting action is
not objectionable and where the inertia of the moving parts is relatively small.
Positive clutches
164
are used when the shafts are virtually collinear and when they remain in a
fixed angular relation with respect to each other (except for angular deflection).
Rigid couplings
165
is essentially a split and bolted sleeve coupling, proportioned to
clamp firmly on the shafts
Clamp shaft coupling
166
are commonly used in permanent installations for heavy loads and large
sizes and particularly for vertical drives, as agitators
Flange face coupling
167
are designed to connect shafts which are misaligned either laterally or
angularly. A secondary benefit is the absorption of impacts due to fluctuations in shaft torque
or angular speed.
Flexible couplings
168
The hubs have integral external gear teeth, perhaps crowned, that mesh with internal teeth in
the casing through 360° as in a splined connection. Flexibility is obtained by play between
the teeth
Gear-type coupling
169
Eliminates the need for large clearances and the resultant noisy backlash by providing a
double-tongued central slider fitting between two flanges slotted at right angles to each other
Oldham (double slider) coupling
170
The rubber-bushed coupling cushions by means of steel pins bolted alternately to one flange
and sliding in self-lubricated bronze bushings, rubber-cushioned in the opposite flange. The construction permits free axial movement to accommodate motor end play and
is especially suited to damping shock and momentary overload. It also affords electrical
insulation, thus preventing such dangers as electrolysis in direct motor-driven pumps.
Rubber-bushed coupling
171
The two opposing hubs are made with integral sprockets over which a double roller chain is
fitted. The drive is through the chain. Flexibility is obtained by lateral play in the fit
of the chain over the sprocket teeth.
Roller chain flexible coupling
172
In a rubber-flexible coupling, the torque is transmitted through a comparatively soft rubber in
compression. It is recommended where quietness is desired
Rubber-flexible coupling
173
are used to connect shafts with much larger values of misalignment than can
be tolerated by the other types of flexible couplings
Universal joint
174
synthetic organic material, including cellulose derivatives, with or without the incorporation
of fillers, binders, pigments, dyes, which is capable of being shaped more or less permanently
by casting or molding under increased temperatures and pressures
plastic
175
simple unpolymerized form of chemical compound
monomer
176
chemical compound with higher molecular weight consisting of a number of structural units
linked together by covalent bonds
polymer
177
polymers consisting of more than one monomer
copolymer
178
non-ionic chemical bond formed by stored electrons
covalent
179
substances that melt on heating and are processes in this state by a variety of extrusion and
molding process
thermoplastic
180
substances that cannot be melted and remelted
thermosets
181
temperature at which the plastic can withstand without incurring a change in its physical
properties
service temperature
182
provides high strength and stiffness while offering enhanced dimensional stability and
ease of machining. A semi-crystalline material, acetal also has a low coefficient of friction
and good wear properties-especially in wet environments. Because it absorbs little moisture,
acetal demonstrates excellent stability for close-tolerance machined parts. In high-moisture or
submerged applications, acetal bearings outperform nylon 4 to 1. This material is resistant to
a wide range of chemicals, including many solvents. And it is available in a broad range of
grades (see below), with properties addressing specific needs.
Acetals
183
shall be made from virgin acrylic monomer and offers superior optical clarity
and light transmission. It shall not affected by sunlight; it resists aging; and it remains stable
across a wide range of temperature, moisture, and exposure conditions. It will not crack,
craze, or corrode. Cast acrylic is preferred for some industrial and commercial applications
because of its optical superiority over molded or extruded acrylic products. Cast acrylic can
be machined or cemented and, with standard equipment, will fabricate like wood, metal, or
other plastics. It weighs half as much as comparable glass and yet has good shatter resistance
and durability.
Cast acrylic
184
also known as nylon is one of the most versatile and widely used thermoplastic
materials. Its physical properties and reasonable price combine to make it a popular choice
for numerous applications. It can replace steel, brass, bronze, aluminum, wood, and rubber,
while reducing noise, using less lubrication, and increasing gear life. Using standard
metalworking equipment, nylon can easily be machined and fabricated into precision parts.
Polyamide (Nylon)
185
is an amorphous thermoplastic with excellent dimensional stability and good
strength and stiffness over a wide range of service temperatures. It is often used for structural
applications when transparency and impact strength are essential-such as lenses, manifolds,
site glasses, and machine guards. Polycarbonate suits a wide variety of electrical applications
as well, because of its low moisture absorption, good insulation and excellent flammability
rating.
Polycarbonate
186
is noted for its light weight, being less dense than water; it is a polymer of
propylene. It resists moisture, oils, and solvents. Since its melting point is 121°C (250°F), it
is used in the manufacture of objects that are sterilized in the course of their use.
Polypropylene
187
more popularly known as Teflon is based on chain of carbon atoms,
the same as all polymers. Given their good dynamic mechanical properties and sufficient
flexibility, PTFE and modified PTFE-based materials are ideally suited for use as dynamic
seals and bearings, even when the stress is extreme.
Polyterafluoroethylene (PTFE)
188
is a thermoplastic that is a polymer of vinyl chloride. Resins of
polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can
be made. This plastic has found extensive use as an electrical insulator for wires and cables.
Polyvinyl chloride (PVC)
189
type of plywood intended for outdoor or marine uses, also known as Type I
exterior plywood
190
surface of the plywood showing veneer of higher grade than that of the back side
face
191
plywood faced with a material other than wood, such as metal or plastic
face-plywood
192
panel made of consolidated ligno-cellulosic fibers with the primary bond derived from their
inherent adhesive properties and/or the addition of resin or other materials
fiberboard
193
consist essentially of an inorganic hydraulic binder or a calcium silicate binder formed by the
chemical reaction of a siliceous material and a calcareous material reinforced by organic
fibers and/or inorganic synthetic fibers
fiber-cement flat sheets
194
type of plywood intended for inside use, having limited moisture resistance
interior plywood
195
side board made up of well machined lumber strips properly dried and glued together
lumber core
196
ply board
plywood made up of face/back veneer, crossboard core veneer and well composed kiln dried
lumber core
lumber core plywood
197
sheet of plywood
panel
198
board principally made from wood chips and formed by hot press process with adhesive
particle board
199
stratum or layer used in referring to the successive layers of veneer in a panel
ply
200
assembled product made of layers of veneers and/or lumber core held together by an
adhesive, the chief characteristics of which is the alternate cross layers, distributing the
longitudinal wood strength
plywood
201
```
This bonding class is appropriate for veneer plywood intended for use in normal interior
climates.
```
Class 1 (dry conditions)
202
```
This bonding class is appropriate for veneer plywood intended for protected external
applications (e.g. behind cladding or under roof coverings), but capable of resisting weather
exposure for short periods (e.g. when exposed during construction). It is also suitable for
interior situations where the service moisture condition is higher than the class 1 level.
```
Class 2 (humid conditions)
203
```
This bonding class is designed for veneer plywood intended for exposure to weather over
sustained periods.
```
Class 3 (exterior conditions)
204
A high density fiberboard without subsequent treatment generally intended for interior use.
Standard fiberboard
205
A high density fiberboard that has been specially treated with drying oil, petroleum
derivatives or other compounds stabilized by baking or heating, and generally intended for
the use where moisture resistance is required.
Tempered fiberboard
206
A hardboard without any factory-applied finish.
Plain
207
High density fiberboard with a smooth surface on one side and a screen impression on the
other side.
Smooth-one-side (S1S)
208
High density fiberboard with smooth surfaces on both sides.
Smooth-two-sides (S2S)
209
Hardboard which has a pattern impressed on one surface, e.g. simulating some other
materials such as leather, sawali, wood grain, bark, diamond, fine weave, and others.
Decorative
210
Usually S1S hardboard with holes punched or drilled at the factory for use with various
fixtures to provide decorative wall-mounted storage facilities or which may be used for
acoustic purposes.
Perforated
