Mechanical Drawing (MDP 115) FirstYear, Mechanical Engineering Dept., Faculty of Engineering, Fayoum University Dr. Ahmed Salah Abou Taleb

Aims of the course This module is designed to provide students with an analysis of mechanical drawings. Comprehensive study of fasteners. Methods of assembling various mechanical parts together with and without locking devices (working drawings, dimensional tolerance, fits, surface finishing).

Course Outlines Part One: Review. Dimensions, Limits, Fits and Tolerance. Surface Roughness. Standard Machine Elements (threads, fasteners, Keys, spline, gears, pulleys, bearing, …….). Welding and Riveting Conventions.

Course Outlines (Cont.) Part Two: Introduction to Computer Graphics. Wire Frame. Applying solid modeling of mechanical components. Assembly drawing. Production Drawing.

Teaching and Learning Methods Power Point Lectures. Computer Program (Auto CAD). Class Work Drawings. Home Work Assignments. Quizzes.

Weighting of Assessment Final Exam 80 Mid Term Exam 20 Class Work Drawing Home Work Assignment Oral 10 Total Marks 150

Review - Instruments The following is the list of drawing instruments and other drawing materials required for preparation of drawing work: Drawing board T-Square Set- Triangles – (30o – 60o and 45o) Instrument box consists of compasses and dividers Mechanical Pencil Rubber or eraser Erasing shield Scotch-tape Duster or handkerchief Drawing sheet

Review - Basic Line Types Name according to application Types of Lines Appearance Continuous thick line Visible line Continuous thin line Dimension line Extension line Leader line Dash thick line Hidden line Chain thin line Center line NOTE : We will learn other types of line in later chapters.

Review - Drawing Scales Length, size Scale is the ratio of the linear dimension of an element of an object shown in the drawing to the real linear dimension of the same element of the object. Size in drawing Actual size :

Review - Drawing Scales Designation of a scale consists of the word “SCALE” followed by the indication of its ratio, as follow SCALE 1:1 for full size SCALE X:1 for enlargement scales (X > 1) SCALE 1:X for reduction scales (X > 1) Dimension numbers shown in the drawing are correspond to “true size” of the object and they are independent of the scale used in creating that drawing.

THE OBJECT IS ASSUMED TO BE SITUATED IN FIRST QUADRANT FIRST ANGLE PROJECTION FOR T.V. IN THIS METHOD, THE OBJECT IS ASSUMED TO BE SITUATED IN FIRST QUADRANT MEANS ABOVE HP & INFRONT OF VP. V.P. P.P. S.V. F.V. OBJECT IS INBETWEEN OBSERVER & PLANE. OBJECT X Y VP HP PP FV LSV TV FOR S.V. FOR F.V. ACTUAL PATTERN OF PLANES & VIEWS IN FIRST ANGLE METHOD OF PROJECTIONS

FRONT FRONT

FRONT TOP TOP FRONT

FRONT SIDE VIEW TOP TOP SIDE VIEW FRONT

orthographic projection TOP SIDE VIEW FRONT SIDE VIEW TOP SIDE VIEW First angle orthographic projection TOP SIDE VIEW FRONT

DRAW THREE VIEWS OF THIS OBJECT BY FIRST ANGLE PROJECTION METHOD FOR T.V. ORTHOGRAPHIC PROJECTIONS FRONT VIEW L.H.SIDE VIEW X Y FOR F.V. FOR S.V. TOP VIEW PICTORIAL PRESENTATION IS GIVEN DRAW THREE VIEWS OF THIS OBJECT BY FIRST ANGLE PROJECTION METHOD

GRAPHICS COMMUNICATION WITH ENGINEERING DRAWING Object Orthographic Projection Dimensioning Working drawing Orthographic projection (convention) Clear ? No Section Views Yes Section views convention Finish

PURPOSES OF SECTION VIEWS Clarify the views by reducing or eliminating the hidden lines. revealing the cross sectional’s shape. Facilitate the dimensioning. Let See the example

EXAMPLE : Advantage of using a section view.

SECTION LINING Section lines or cross-hatch lines are used to indicate the surfaces that are cut by the cutting plane. Section lines Drawn with 4H pencil.

FULL SECTION VIEW The view is made by passing the straight cutting plane completely through the part.

TREATMENT OF HIDDEN LINES Hidden lines are normally omitted from section views.