Sketching & Drawing Sketching & Drawing ProjectsProjects

Unit 18Unit 18

ObjectivesObjectives

• Describe the difference between a sketch Describe the difference between a sketch and a drawing and explain the different and a drawing and explain the different type of drawings.type of drawings.

• Describe the procedures used to make Describe the procedures used to make mechanical drawings.mechanical drawings.

• Properly letter drawings and sketchesProperly letter drawings and sketches• Draw and sketch different views of objectsDraw and sketch different views of objects• Read and interpret plan drawingRead and interpret plan drawing• Prepare a bill of materials from a sketch or Prepare a bill of materials from a sketch or

plan drawingplan drawing

IntroductionIntroduction

• Why??????Why??????– Represent the shapes and sizes of objectsRepresent the shapes and sizes of objects– Aids in developing functional ideas on paper.Aids in developing functional ideas on paper.– Aids in construction and repairs according Aids in construction and repairs according

specificationsspecifications– Reduces the amount time, money, and Reduces the amount time, money, and

materials needed for a project.materials needed for a project.– Aids in without the use of expert assistanceAids in without the use of expert assistance

Sketches & DrawingsSketches & Drawings

• SketchesSketches– SimplySimply– Rough outline of an objectRough outline of an object– Can be made freehand or a straightedgeCan be made freehand or a straightedge– Not drawn to scaleNot drawn to scale– Sketches of small, simple projects with Sketches of small, simple projects with

proper dimensions can be sufficientproper dimensions can be sufficient

Sketches & DrawingsSketches & Drawings

• DrawingsDrawings– Requires scaled drawingRequires scaled drawing– Made with drawing instrumentsMade with drawing instruments– Pencil and ink are usedPencil and ink are used– Usually ink over pencil for plans kept for Usually ink over pencil for plans kept for

long periods.long periods.

Pictorial DrawingPictorial Drawing

Pictorial drawings shows all three Pictorial drawings shows all three dimensions at oncedimensions at once

SymbolsSymbols

• Border lineBorder line – a heavy, solid line drawn – a heavy, solid line drawn parallel to the edges of the drawing paper.parallel to the edges of the drawing paper.

• Object lineObject line – a solid heavy line, less than – a solid heavy line, less than border lines, showing visible edges and form border lines, showing visible edges and form of an object.of an object.

• Hidden lineHidden line – a series of dashes that – a series of dashes that indicates or shows the hidden features of a indicates or shows the hidden features of a part.part.

• Dimension lineDimension line – a solid line with arrowheads – a solid line with arrowheads at the ends to indicate the length, width, or at the ends to indicate the length, width, or height of an object or part.height of an object or part.

SymbolsSymbols

• Extension lineExtension line – a solid line showing the – a solid line showing the exact area specified by a dimension.exact area specified by a dimension.

• Break lineBreak line – a solid, zigsag line used to – a solid, zigsag line used to show the illustration stops but the object show the illustration stops but the object does not.does not.

• Center lineCenter line – a long-short-long line used – a long-short-long line used to indicate the center of a round object.to indicate the center of a round object.

• Leader lineLeader line – a solid line with an arrow – a solid line with an arrow used with an explanatory note to point to used with an explanatory note to point to a specific feature of an object.a specific feature of an object.

How to Sketch a Horizontal How to Sketch a Horizontal LineLine

11stst – mark off two points spaced a – mark off two points spaced a distance equal to the length of the distance equal to the length of the line to be drawn. Points should be line to be drawn. Points should be parallel to the top or bottom of the parallel to the top or bottom of the page.page.

.. ..

How to Sketch a Horizontal How to Sketch a Horizontal LineLine

22ndnd –Move your pencil back and forth –Move your pencil back and forth and connect these points with a and connect these points with a construction line.construction line.

33rdrd –Start from left point and sketch an –Start from left point and sketch an object line to the right point. This object line to the right point. This line is sketched over the construction line is sketched over the construction line.line.

How to Sketch a Vertical How to Sketch a Vertical LineLine

11stst – mark off two points spaced a – mark off two points spaced a distance equal to the length of the line distance equal to the length of the line to be drawn. Points should be parallel to be drawn. Points should be parallel to the left or right side of the page.to the left or right side of the page.

22ndnd –Move your pencil back and forth –Move your pencil back and forth and connect these points with a and connect these points with a construction line.construction line.

How to Sketch a Vertical How to Sketch a Vertical LineLine

33rdrd –Start from left point and sketch an –Start from left point and sketch an object line to the right point. This object line to the right point. This line is sketched over the construction line is sketched over the construction line.line.

How to Sketch an Inclined How to Sketch an Inclined LineLine

11stst –Mark off two points at the desired –Mark off two points at the desired angle. Connect these points with a angle. Connect these points with a construction line.construction line.

22ndnd—Sketch the desired weight line —Sketch the desired weight line over the construction line. Sketch up over the construction line. Sketch up when the lines inclines to the right. when the lines inclines to the right. Sketch down when the line inclines Sketch down when the line inclines to the left.to the left.

How to Sketch Squares & How to Sketch Squares & RectangleRectangle

See handout.See handout.

How to Sketch AnglesHow to Sketch Angles

See handouts.See handouts.

How to Sketch CirclesHow to Sketch Circles

See Handout.See Handout.

How to Sketch an ArcHow to Sketch an Arc

See handoutSee handout

How to Sketch an EllipseHow to Sketch an Ellipse

See handoutSee handout

How to Sketch a HexagonHow to Sketch a Hexagon

See handoutSee handout

How to Sketch an OctagonHow to Sketch an Octagon

See Handout.See Handout.

Scale DrawingScale Drawing

• ScaleScale is the size of a plan or drawing is the size of a plan or drawing as compared to that of the object it as compared to that of the object it represent.represent.

Types of DrawingsTypes of Drawings

• Orthographic drawingsOrthographic drawings

• Pictorial drawingsPictorial drawings

Orthographic DrawingsOrthographic Drawings

• Shows separate views of an objectShows separate views of an object– TopTop– FrontFront– End or sideEnd or side

These views are referred to as working These views are referred to as working drawingsdrawings

Pictorial DrawingsPictorial Drawings

• Two basic types – isometric & obliqueTwo basic types – isometric & oblique

Shows three views of the object Shows three views of the object together which resembles a picture together which resembles a picture of the object to be madeof the object to be made

Orthographic ViewsOrthographic Views

Pictorial ViewPictorial View

..

Mechanical Drawing Mechanical Drawing EquipmentEquipment

• Drawing BoardDrawing Board– 20” X 26” softwood, free of knots20” X 26” softwood, free of knots– Accommodate 17” x 22” paperAccommodate 17” x 22” paper– Left and right edges of the board must Left and right edges of the board must

be straightbe straight

TrianglesTriangles

• 45 degree triangles45 degree triangles

• 30-60-90 degree triangles30-60-90 degree triangles

Isometric DrawingIsometric Drawing

Three views to transfer to an objectThree views to transfer to an object

toptop

frontfront

sideside

THE BOXTHE BOX

toptop

front sidefront side