The Use of the Scale
Chapter 3
Sacramento City College
EDT 300/ENGR 306
EDT 300/ENGR 306
1
Scales
‹ Scales
are used for laying off distances and
for making measurements.
‹ Scales
are made in various shapes.
‹ Flat.
‹ Triangular shape.
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Scales
‹ Usually
made of:
‹ Boxwood.
‹ Plastic.
‹ Plastic on boxwood.
‹ Metal.
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Scales-Open or Fully Divided
‹ Some
scales are “open-divided” with only the
end units subdivided.
‹ Figure 3-33B and 3-33C.
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Scales-Open or Fully Divided
‹ Some
scales are “open-divided” with only the
end units subdivided.
‹ Figure 3-33B and 3-33C.
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Scales-Open or Fully Divided
‹ Others
are fully divided with subdivisions over
their entire length.
‹ Figure 3-33D and 3-33E.
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Scales-Open or Fully Divided
‹ Others
are fully divided with subdivisions over
their entire length.
‹ Figure 3-33D and 3-33E.
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Scale Types
‹ Different
types of scales are used to make
different kinds of drawings.
‹ Architect’s scale.
‹ Mechanical Engineers scale.
‹ Civil engineers scale (decimal scale).
‹ Metric Scale.
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Scale Types - Architect
‹ Architect’s
scale.
‹ Is used by architects primarily for
producing drawings of buildings.
‹ Is graduated in fractions of an inch.
‹ Is divided into proportional feet and inches.
‹ Typical
architectural drawing scales:
‹ 1/4” = 1’-0”
‹ 1/8” = 1’-0”
‹ 1-1/2” = 1’-0”
‹ 3” = 1’-0”
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The Architect’s Scale
‹ The
triangle shape is used most commonly.
‹ It has many scales on a single stick.
‹ Some drafters prefer flat scales especially
when they do not have to change scales
often.
‹ Refer to Figure 3-33.
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The Architect’s Scale
‹ The
triangle shape is used most commonly.
‹ It has many scales on a single stick.
‹ Some drafters prefer flat scales especially
when they do not have to change scales
often.
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Scale Types - Mechanical Engineers
‹ Mechanical
Engineer’s Scale.
‹ Has inches and fractions of an inch divided
to represent inches.
‹ Divisions
‹ Full
size - 1 inch divided into 32nds.
‹ Half size - 1/2 inch divided into 16ths.
‹ Quarter size - 1/4 inch divided into 8ths.
‹ Eighth size - 1/8 inch divided into 4ths.
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Scale Types - Mechanical Engineers
‹ Mechanical
Engineer’s Scale.
‹ Is used for drawing parts of machines.
‹ Is used for applications where larger
reductions in scale are not needed.
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Scale Types - Civil Engineers
‹ Civil
‹1
engineers scale (decimal scale).
inch can represent several quantities
‹ Feet.
‹ Rods.
‹ Miles.
‹ Etc.
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The Civil Engineer’s Scale
‹ Divisions
are inches divided into decimals.
‹ The usual divisions are:
‹ 10 parts to the inch.
‹ 20 parts to the inch.
‹ 30 parts to the inch.
‹ 40 parts to the inch.
‹ 50 parts to the inch.
‹ 60 parts to the inch.
‹ The inch may represent different quantities
such as feet, rods, miles, and so forth.
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The Civil Engineer’s Scale
‹ In
addition, the divisions may be single units
or multiples of 10, 100 or 1000.
‹ Example:
20 parts to an inch scale may
represent
‹ 20
‹ 200
‹ 2,000 units.
‹ The scale is used for Civil Engineering work
‹ Maps and drawings of roads.
‹ Site plans.
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The Civil Engineer’s Scale
‹ The
scale used should be given on the
drawing.
‹ Scale: 1” = 500 feet.
‹ Scale: 1” = 100 feet.
‹ Scale: 1” = 200 miles.
‹ Scale: 1” = 100 miles.
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Proportional Scales
‹ Proportional
scales are used in drawing
buildings and in making mechanical, electrical
and other engineering drawings.
‹ The
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proportional scale to which the views are
draw should be given on the drawing.
‹ This usually is indicated in the title block if
only one scale is used.
‹ Common proportional scales:
‹ 6” = 1’-0”
‹ 3” = 1’-0”
‹ 1-1/2” = 1’-0”
Scale Types - Metric
‹ The
proportional metric scale can be used on
all types of engineering drawings when metric
units are used.
‹ Remember,
the metric system allows easy
conversion from one unit to another.
‹ Meters
‹ Decameters
‹ Hectometers
‹ Kilometers
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The Metric Scale
‹ The
Metric Scale is divided into millimeters.
‹ Used
for Architectural, Mechanical, Electrical
drawings.
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Metric Proportional Scale
Enlarged
2000:1
100:1
500:1
100:1
50:1
20:1
10:1
5:1
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Same size
Reduced
1:1
1:2
1:10
1:20
1:50
1:100
1:500
1:1000
1:2000
Dimension Notation
‹ The
symbol (’) is used for feet and (”) is used
for inches.
‹ Three
feet four and one-half inches is written
‹ 3’-4 1/2”.
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Indicating Drawing Scale
‹ The
scale of a drawing is ALWAYS indicated
on the drawing.
‹ If
different parts of the drawing have
different scales, the scales are given near the
views.
‹ If
multiple scales are used they should be
clearly indicated on the drawing.
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Using A Scale
EDT 300/ENGR 306
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Using A Scale
‹A
drawing is created “to scale” under the
following conditions:
‹ When
the object being drawn is too large
for the drawing sheet.
‹ When
the object being drawn is too small
to be read easily.
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Using A Scale
‹ When
the object being drawn is too large for
the drawing sheet.
‹ Buildings.
‹ Property.
‹ Roads.
‹ Campuses.
‹ Airports.
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Using A Scale
‹ When
the object being drawn is too small to
be read easily.
‹ Computer chip drawings.
‹ Small mechanical parts.
‹ Biomedical devices.
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Full-Size Drawings
‹ When
the object being drawn will fit on the
paper on which you are drawing it, draw it
full-size or full-scale (1:1).\
‹ ALWAYS
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try to draw full-scale FIRST !
Drawings To Scale
‹ If
you cannot draw full-scale, choose the
largest scale that will fit on the sheet.
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Drawing With A Scale
EDT 300/ENGR 306
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Drawing With A Scale-Full Size
‹ If
you draw an object FULL-SIZE, just
transfer the dimensions directly.
‹ 1. Measure the distance of the object.
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‹ 2.
Align the “0” with one end of the object.
‹ 3.
Read the length on the scale.
‹ 4.
Draw a line representing that distance.
Drawing With A Scale-Half Size
‹ If
you must draw the object HALF-SIZE and
only had a FULL-SIZE scale, you would
‹ 1. Measure the distance of the object.
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‹ 2.
Align the “0” with one end of the object.
‹ 4.
Convert the measured distance to half.
‹ 5.
Draw the half distance on the paper.
Drawing With A Scale-Full Size
‹ Drawing
Full-Size with the Full Size scale:
‹ Measure the actual distance.
‹ Draw the actual distance.
‹ Very
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easy !
Drawing With A Scale-Full Size
‹ Drawing
Half-Size with the Full Size scale:
‹ Measure the actual distance.
‹ Mentally divide the distance in half before
drawing the distance on the sheet.
‹A
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real pain in the neck !
Measuring With A Scale Half Size
‹A
Better Idea - Use a Half-Size Scale
‹ Let the scale “do the work for you.”
‹ Think full-size, all the time.
‹ The scale would automatically convert for
you.
‹ Same
example: with the half-size scale:
‹ Measure the actual distance directly.
‹ Draw the distance with the half-size scale
using the same dimension directly on the
scale.
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‹ (no
mental math required)
Think “FULL SIZE”
‹ When
using a scale, ALWAYS think FULL SIZE
‹ Let the scale “do the work for you”.
‹ The
scale will automatically produce the
proper reduction.
‹ All
you have to be concerned with is making
accurate readings on the scale.
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Proportional Scale Chart
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Proportion
Gradation
Ratio
Full size
1/4 size
1/8 size
1/12 size
1/16 size
1/24 size
1/32 size
1/48 size
1/64 size
1/96 size
1/128 size
12” = 1’-0”
3” = 1’-0”
1-1/2” = 1’-0”
1” = 1’-0”
3/4” = 1’-0”
1/2” = 1’-0”
3/8” = 1’-0”
1/4” = 1’-0”
3/16” = 1’-0”
1/8” = 1’-0”
3/32” = 1’-0”
1:1
1:4
1:8
1:12
1:16
1:24
1:32
1:48
1:64
1:96
1:128
Open Divided Architect Scale
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Open Divided Architect Scale
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Open Divided Architect Scale
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Making Measurements
EDT 300/ENGR 306
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Measuring With A Scale
‹ To
make a measurement with a scale:
‹ 1.
Place the scale on the paper in the
direction in which you are measuring.
‹ 2.
‹ 3.
Align the “0” with one end of the object.
Read the exact length from the
graduations on the scale.
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Making Measurements
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Making Measurements
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Making Measurements
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Making Measurements
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