Notes on Mechanical Drawing

Oct 25, 2026

Uploaded by Kurz

Drawing is presented as a necessary medium of expression for engineers, enabling accurate presentation of ideas beyond textual description. The text explains the distinction between artist sketches and technical working/mechanical drawings, including the use of scaled views and lines to define shape and size precisely. It emphasizes the importance of both reading and executing drawings, then outlines requirements for a good draftsman—neatness, accuracy, and speed—followed by guidance on selecting drawing instruments and materials.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages72

Reading Time3 h 1 min

AccessFree to download

Notes on Mechanical Drawing

Drawing Instruments and Materials

Selection of Drawing Instruments

The Necessary Outfit

Drawing Board

T-Square

7353W27 吗 353 6d # INDUSTRIAL EDUCATION NOTES ON MECHANICAL DRAWING ByROLLAND S.WALLIS A SUPPLEMENT TO THE DRAWING COURSESCONDUCTED BY THEENGINEERING EXTENSION DEPARTMENT COPYBIOHT,1922,BY T日 ENGINEERING EXTENSION DEPARTMENTIOWA STATE COLLEGEAMES,IOWA 1pv376IQ?.Nn? 71!L9V1◎ 35327 同 # Notes on Mechanical Drawing By ROLLAND S.WALLIS Drawing is a medium of expression necessary to the engineer.Byits use he is enabled to present the details of his ideas far more effect-ively than could be done by deseription in words.In fact,it wouldbe an almost hopeless undertaking to attempt the written descriptionof a complicated machine so that it could be aceurately reproduced bya workman. )Blockwog-s1non Fig.1.—An artist's sketch(a)and a working drawing(b). An artist's sketch(Fig.1a)is of value in presenting general ideas,but the demands made on the technical draftsman are much more ex-acting.He must show with mathematical exactness the shape and thesize of each piece he wishes to represent,and frequently the aceuraterelation of various parts of a complicated machine or structure.Toaccomplish this he usually makes what are ter.med"working draw-ings"or'mechanieal drawings."Each of these(Fig.1b)consists ofa set of two or more different views of the machine or structure,ar-ranged in accordance with a definite system generally understood byengineers,and with the necessary lines and figures added to show thesize and shape of its parts. Such drawings are usually made to scale and executed with draftinginstruments.Strictly speaking,all drawings made with instrumentsmay be termed mechanical drawings,but the term is generally takento refer to engineering or working drawings.The technical drafts-man represents by means of outline drawing,making little or no use ofshading to represent depth or relief. The ability to read drawings is vital to all connected in any way with technical industry,while the added ability to execute such draw-ings neatly and quickly is as essential to an engineer as is a knowl-edge of practical mathematics. Requirements of a Good Draftsman.—A good draftsman is neat andaccurate and works rapidly.Neatness in drafting includes the ar-rangement and finish of line work and lettering,as well as cleanliness.Accuracy can be attained by care in the use of the seale and by keep-ing pencil points and drafting instruments in proper condition.Speedis desirable up to the point where it conflicts with neatness and ac-curacy.It may be attained by systematic procedure in all routineoperations. # Drawing Instruments and Materials Selection of Drawing Instruments.—The beginner is cautionedagainst the common error of purchasing cheap tools,as this is mistakeneconomy.A satisfactory quality of materials and workmanship neces-sarily means increased cost over inferior instruments which are worth-less for accurate work and expensive at any price.There is usuallyenough to oecupy the mind of a beginner without the perpetual annoy-ance attending the use of poor tools. The assistance and advice of an experienced draftsman will provevaluable in the selection of drafting instruments and supplies,as thedifferences in material and workmanship are usually not readily ap-parent to one not aceustomed to handling them.Small variationsfrom the sizes given in the suggested list are permissible. The Necessary Outfit.—The following instruments and materialswill be required by the student: Set of drawing instruments,including: Compasses(6-inch)with extension bar,fixed needle-point,and re-movable pen and pencil-points.Dividers(51/2-inch)Ruling pen(5-inch)Bow peneilBow penBow dividers Drawing board(16"x22")T-square(24-inch)Triangle(45°,6-inch)Triangle(30°-60°,9-inch)French curve Architects'seale(12-inch,triangular)Engineers'seale(12-inch,triangular)Thumb tacksDrawing pencils(H and 3H) Drawing paper(11"x15"sheets,white) Pencil eraser(Fabers'Ruby,"No.112,or equivalent)Cleaning eraser(or‘Art-Gum') Pencil pointe

FAQs

Why is mechanical drawing important for engineers?

Drawing enables engineers to present detailed ideas with mathematical exactness that written description cannot achieve for complex machines.

What makes working drawings different from an artist’s sketch?

Working drawings require precise shape and size, using a systematic set of multiple views with lines and figures to show accurate relationships among parts.

What are the requirements of a good draftsman?

A good draftsman is neat and accurate, works rapidly, maintains clean line work and lettering, uses scale carefully, keeps instruments in proper condition, and follows systematic procedures in routine work.

Oct 25, 2026

Uploaded by Kurz