MISS. HANNA S CLASSROOM RULES 1. My students never fail. I believe in you and so shall you! Miss. Hanna s Quote! 2. Come to class on time. 3. Bring a positive attitude. 4. Come prepared and bring your books and notes. 5. Stay on task. 6. Complete work on time. 7. Pay attention and don t talk while the teacher is talking. 8. Listen carefully. 9. Raise your hand to ask a question. 10.Work quietly. 11.No personal grooming, electronics which will disturb the class and other students who are working. 12.Respect personal space. 13.Ensure chairs and tables are in order before leaving class. 14.Be kind with your words and actions. 15.Respect, obey and follow all school rules and personal property. 16.Work in a safe manner. I appreciate and thank all my students for their effort in respecting and keeping up with our classroom rules!
Introduction to Drawing Tools A video or 2 for you Basic Engineering Drawing http://www.youtube.com/watch?v=ffdh ScQFscw Orthographic: http://www.youtube.com/watch?v=vsnvo 5rl66w 2
Introduction to Drawing Tools Module Objectives Identify and describe the use of engineering drawing equipment. Recognize different methods of laying out engineering drawing papers. Demonstrate the use of scales. Produce a simple drawing paper layout including border and title block.
1.0 Introduction Technical drawing is the study of the procedures, tools, supplies, skills and techniques used to record and communicate the shape and size of a product. Every product we have today (e.g. cars, houses, machines, etc ), began as an "idea" in some person's head. Before these "ideas" became products, they had to be drawn on paper so as to show what the idea looks like from different directions, Fig.1.1. Fig 1.1. 4
2.0 Drawing instruments To prepare a drawing, one can use manual drafting instruments as shown in Fig.1.2, or computer-aided drafting (CAD). If the drawing is made without either manual instruments or CAD, it is called a freehand sketch. The following instruments are essential and should be available to produce a good quality technical drawing. Fig. 1.2: Manual Instruments 5
2.1 Drawing Boards Drawing Boards can range from simple boards, like the one shown in Fig.1.3, to complicated drawing machines that would be used in engineering drawing office. The surface of the board should be dusted and smooth. Fig. 1.3: Drawing Board 6
2.2 T-Square T- Square is composed of a long strip, called the blade; it is placed on the drawing board and provides a constant horizontal edge. The T-square is shown in Fig.1.4 below. 7
2.3 Set Square Set Squares are best made from transparent plastic. The two standard set squares that are commonly used are 30/60 and 45/45 degrees triangles as shown in Fig 1.5. 45/45 triangle 30/60 triangle 8
2.4 Pairs of Compasses There are basically two types of compasses 1. Pencil compasses which are used to draw circles. Circles up to 300 mm diameter are drawn using a large radius compass. 2. Spring bow compass which is used to draw circles of 50 mm diameter or less. (Fig.1.6) to the right. 9
2.5 Protractor Protractors measure angles other than those obtained by the set squares and found in half circle or full circle types, Fig. 1.7 shown below. 10
2.6 Ruler A 300 mm ruler with one edge marked in centimeters and millimeters is necessary, Fig.1.8 below. In a fully equipped drawing machine, horizontal and vertical rulers with graduations in mm or inches are attached to the drafting head. 11
2.7 Drawing pencils Pencils have nine grads of hardness from H to 9H and seven grades of softness from B to 7B as shown in Fig. 1.9. Fig.1.9: Pencil lead grades. 12
2.6 Eraser Erasers are available in different hardness and are used to erase pencil work. The common eraser used is a block-shaped vinyl eraser (Fig.1.10). 13
2.8 Circle template Circle templates are useful for drawing small circles quickly and to join lines with a radius, A circle template is shown in Fig.1.11. 14
3.0 Drawing Paper 3.1 Sizes of the drawing paper Drawing paper is available in A series, B series, and rolls of the International Organization for standardization (ISO), but series A is preferred. Paper sizes for series A are based on the A0 size, which has an area of 1 square meter. An A0 size sheet can be divided up evenly into the various other sizes (A1, A2, A3, A4 ) simply by halving the sheet on the long side in each case as shown in Fig. 1.12 on page 6 in Module 1. 15
3.2 Scales In order to produce drawing showing components in detail or as plans it is often necessary to use a scale. This can increase the size of the drawing in comparison to the real size of the component. Some of the recommended scales are listed below: Enlargements scales: 2:1 20:1 50:1 10:1 Full (same) size: 1:1 Reduction scales: 1:2 1:10 1:20 1:100 16
3.3 Layout of the drawing paper Drawing sheets of all sizes have standard layout. It is usual for each sheet to be provided with a drawing frame a short distance from the edge of the paper as shown in Fig.1.13 shown on page 6 Module 1. Each drawing sheet has to be provided with a title block which represents the general information source for a drawing. It is normally placed in the bottom and at least contains the title of the drawing, the name of the draftsman, the scale, and the date. 17
Fig 1.13 a: Layout of the A3 drawing paper.
Fig 1.13 b: Layout of the A4 drawing paper. INSTITUTE OF APPLIED TECHNOLOGY 19
3.4 Line type Fig. 1.14 (on page 7 in Module 1) shows the types of line which are commonly used in engineering drawings such as visible lines, hidden lines, center lines, dimension lines, extension lines, and leader lines. Fig. 1.15 (on page 7 in Module 1) shows an application for the use of different types of Line. 20
4 Main Line Types INSTITUTE OF APPLIED TECHNOLOGY 21
Technique of Lettering Printing increase the information that is provided on a drawing. Printing must be clear and neat so that it is easy to read. Use guide lines 5 mm apart as illustrated in Fig. 1.16. These guide lines can be used to make sure that all letters and numbers have the same size. Always print using capital letters. All letters and numbers should touch the top and bottom guide lines. Guide lines should be 5 mm apart as explained earlier.
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5.1 In class activities Draw the objects shown below in full size using different drawing tools such as compasses, set squares and tee square. Use an A3 sheet to create the drawing with the same layout shown below. 25
5.2 Home work Draw all 4 drawings shown on page 9 & 10 in Module 1 Submission date Due next class 26
Technical Drawing Instruments Students must bring all their drawing instruments next class 27