Preparing Drafting Materials PDF

LESSON 1 Preparing Drafting Materials and Tools/Drawing Instruments I. DRAFTING MATERIALS AND TOOLS, ITS USES/FUNCTION There are a great variety of drafting materials and tools used in mechanical drawing. The drafting materials and...

LESSON 1 Preparing Drafting Materials and Tools/Drawing Instruments I. DRAFTING MATERIALS AND TOOLS, ITS USES/FUNCTION There are a great variety of drafting materials and tools used in mechanical drawing. The drafting materials and tools discussed in this Module include most of the basic ones but sufficient enough for your initial understanding about mechanical drawing. MECHANICAL DRAFTING - a process for making accurate drawings using special drawing tools and instruments. PICTURES / ILLUSTRATIONS MATERIALS, DESCRIPTION AND FUNCTION DRAWING PAPER - Various types of drawing papers are available for use but hard and soft surface drawing papers are highly recommended to be the best. This type does not groove easily when pressure is applied to the pencil. Oslo paper is commonly used but bond paper is also recommended. MASKING TAPE - This is used for fastening the drawing paper on the drawing table or drawing board because it does not damage the board and it will not damage the paper if it is removed by pulling it off. PENCIL SHARPENER - Pencils should be sharpened whenever they show sign of dullness. Various types and designs are available in the store for use. ERASER - This is used to clean the dirt off the drawing. A soft eraser is advantageous in removing smudges and pencil marks, whereas, a harder eraser is useful for making changes and correcting errors in the drawing  DRAWING PENCIL - This is one of the most important tools in drawing. It comes in various grades. The grade of pencil to be used depends on the quality of paper to be used. You have to take into consideration also the type of line work required. 1. HARD PENCILS - are used where extreme accuracy is required especially working on graphs, diagrams and charts. 2. MEDIUM PENCILS - are used for general purpose work in drawing. 3. SOFT PENCILS - are too soft to be used in mechanical drafting. They are very useful for art work of various kinds. TRIANGULAR SCALES - This is a tool generally used when reproducing a drawing in an enlarged or reduced form to some regular proportion. The architect’s scale is the most commonly used for general drawing. Its main function is to reproduce the measurements of an object in full size, reduced size, and enlarged size. ERASING SHIELD - This tool is made up of metal with irregular holes. It is a useful tool to protect the rest of the drawing when clearing up smudges, unnecessary pencil lines and other erasures. FRENCH CURVE - It helps in marking shapes of the neck, depth of sides and garments bottom. Essential tool for perfect shaping armholes, necklines, and collars. DRAWING INSTRUMENTS Drawing instruments are used for drawing and designing purposes. Their quality is very essential if you want to have good result. Cheaper drawing tools and instruments do not only provide poor quality results but also do not last long. You have to observe proper handling and care if you want them. DRAWING - a picture, diagram made of lines, a graphic representation of real thing, an idea or a design for production or construction DETAILED DRAWING - a drawing showing a single part of a machine. GEOMETRICAL CONSTRUCTION - the process wherein geometric problems are solved accurately in mechanical drawings. DIMENSIONING - the process of placing measurements in a drawing in the Metric or English system. ENGLISH SYSTEM - a system of linear measurement where it is based on standard foot. METRIC SYSTEM - a system of linear measurement which it is based on the standard meter. SKETCH - a quickly executed freehand drawing that is not intended as a finished work. PICTURES / ILLUSTRATIONS MATERIALS, DESCRIPTION AND FUNCTION T-SQUARE - It is a drawing instrument used when making horizontal lines. It is also used for guiding triangles when drawing vertical lines. It is made of wood, plastic or the combination of both. There are three (3) types of T- square, namely. 1. FIXED HEAD - The head is fastened to the blade. It is used for ordinary work. 2. MOVABLE HEAD OR ADJUSTABLE HEAD - It has one fixed and one adjustable head and used only for occasional drawing. 3. DETACHABLE HEAD OR REMOVABLE HEAD - It is designed for comfort when carrying the T- square.  TRIANGLE - It is a three-sided ruler, which typically has two equal sides meeting at a 90 degree angle and to a third side at 45, 30, including 60 degree angles. It is usually made of plastic and comes in different sizes. If in use, the base of the triangle must rest on the blade of the T-square. Drawing a line always starts from the point near the base going upward. Commonly used triangles are: a. 30 degrees X 60 degrees b. 45 degrees X 45 degrees COMPASS - This drawing instrument is used when drawing arcs and circles. It is used in a similar way to a divider. It is composed of one with the pen leg and the needle point leg being held together with a handle. This drawing instrument can be used for both penciling and inking. DIVIDER - This is a drawing instrument used when transferring measurements, dividing lines and arcs into the desired number of equal parts. It can easily transfer accurate measurements by adjusting the divider points. Constant correct practice is necessary before doing an actual work for a quick and easy control when use. PROTRACTOR - It is a semi-circular instrument divided into 180 equal parts, each of which is called a degree. It is used to determine gradations of the degrees when measuring arcs, angles and circles. High quality protractor is usually made of plastic. II. PROPER MANIPULATION OF DRAFTING MATERIALS TOOLS AND DRAWING INSTRUMENTS Proper Manipulation of the T-square PROCEDURE: 1. Place the head of the T-square against the edge of the drafting table. (Left side of the table if you are right-handed and at the right side of the table if you are lefthanded). 2. Slide the working head of the T-square against the working edge of the drawing table. The two edges should be in constant contact until the desired position. Note: Do not use the T-square on an uneven or rough surfaces and never cut paper along its working edge Setting up Drawing Paper on the Drawing Table PROCEDURE: 1. Press firmly the T-square against the working edge of the drawing table. 2. Place the drawing paper close to the working edge of the drawing table and working head of the T-square depending on you if you are right or left-handed, while the paper is placed on top edge of the T-square. 3. Fasten the upper left portion of the drawing paper followed by the lower right portion and finally the remaining corners. Note: Always fasten larger backing sheet of thicker drawing paper on the board first. Drawing a Horizontal Line PROCEDURE: 1. Press the head of the T-square against the working edge of the drawing table and lean the pencil to the desired direction of the line inclined at more or less 60degrees with the drawing table. 2. Maintain the position of the pencil while you glide lightly on the blade of the T-square. 3. Draw the line from left to right rotating occasionally to produce uniform line weights. (Reverse this step if you are left-handed). DRAWING A VERTICAL LINE PROCEDURE: 1. Use 45 degrees triangle or 30 degrees x 60 degrees to draw vertical lines. 2. Place the triangle on top of the blade of the T-square with the vertical edge on the left. 3. With the left hand pressing the T-square and the triangle against the drawing board, draw the line upward, rotating the pencil slowly between the thumb and forefinger. III. PROCEDURES IN RECEIVING AND STORING TOOLS AND MATERIALS The RECEIVING DEPARTMENT has the function to: unload and unpack incoming materials; check quantities received against the shippers packing list; identify goods received with descriptions on the purchase order; prepare a receiving report; notify the purchasing department of descriptions discovered; arrange for inspection when necessary; notify the purchasing department of any damage in transit; and rout accepted materials to the appropriate manufacturer’s location. The form also provides a space for the inspection department to note either the complete approval of the shipment or the quantity rejected and the reason for the rejection, in inspection does not take place immediately after receipt of the materials, the receiving report is distributed as follows: The receiving department keeps one copy and sends another copy to the purchasing department as notice of the arrival of the materials. All other copies go to the inspection department, and are distributed when inspection is completed. After inspection, one copy of the receiving report, with the inspection result is sent to the accounting department, where it is matched with the purchase order and the venders' invoice and the paid.  Other copies go to various departments such as materials and production planning. One copy accompanies the materials, so that the storekeeper knows the quantity and the kind of materials received. INVENTORY - Inventory is an idle stock of physical goods that contain economic value, and are held in various forms by an organization in its custody awaiting packing, processing, transformation, use or sale in a future point of time. INVENTORY FORM - The Inventory form contains information about items (name, number, sales and purchase information, and cost of goods sold account information) that any business purchases for sale, tracks in inventory, and displays on a balance sheet. IV. DIFFERENT REQUISITION FORMS AND PROCEDURES VARIOUS FORMS - Accurate entry in different forms used in drafting works is essentially important in order to purchase right, accurate and complete number of drawing materials, tools and instruments needed in a specific drafting job. Here are sample various forms used in drafting works. REQUISITION FORM - an official form, a printed document on which a request is made. A. SAMPLE REQUISITION SLIP FORM - This is an official paper in the form of a printed document on which a request in made. B. SAMPLE PURCHASE REQUISITION FORM - Below is a sample purchase requisition form. For standard materials, little information other than the stock number may be needed and for other purchases requests, it may be necessary to give particular descriptions, blueprints, catalog numbers, weights, standards, brand names, exact quantities to order, and suggested prices. One copy remains with the originating employee, and the original is sent to the purchasing department for execution of the request. C. SAMPLE DELIVERY RECEIPT FORM - Delivery receipt form shows proof or receipt of goods or services. The receiver acknowledges receiving a consignment of goods from supplier. The buyer signs it before it is returned to the seller. This officially takes care of uncertainties on the part of the supplier who gets to know the safe and timely arrival of goods to their designated destination. D. SAMPLE INVENTORY FORM OF DRAWING TOOLS AND INSTRUMENTS E. SAMPLE BARROWER’S SLIP