Engineering Drawing Tools and Equipments
Heel Of Engine room Draught Tools | Drawing Instrument
Engineering drawing off is the language of engineers and technicians. The accuracy and neatness of engineering drawing depends on the quality of the instruments used. With great instruments, the drawing can be prepared easily, quickly and accurately. Therefore, the knowledge of different drawing instruments and materials, methods of using them and the preparatory works to be completed before commencing the lottery is very important.
Read More : What is Technology Drawing | Grassroots of Simple machine drawing
Instruments Used for Drawing
The following drawing instruments are required for preparing a neat and correct drawing.
- Staple Instruments
- Drafting board
- Drawing tabloid
- Draught pencil
- Drawing clips or pins
- Eraser
- Eraser shield
- Instruments for Drawing Straight Lines
- T- square.
- Set- squares
- Instruments for Draught Curved Lines
- Large size compass
- (two) Smallish bow dig '
- French curve
- Instruments for Measuring Distance
- Large size of it splitter
- Infinitesimal bow divider
- Scales
- Instruments for Measuring Angles
- Protractors
- Hardening-squares
- Primary Tool
- Mini drafter
Drafting board – Drawing Board (Top) image shows a drawing circuit card with its running surface upward. The top surface of the board is utterly smooth and horizontal surface. Drawing Board (Bum) image shows the hind end of the drawing board. A draught board is rectangular in shape and is made of well seasoned soft Wood such as oak or pine. A straight ebony edge in is fitted on the left side on the board against which the head of the T- square moves.
Draftsmanship Sheet – The draftsmanship is frequently made in pencil connected the drawing shrou. The best drawing sheet has the following qualities:
- Loose clobber buff in colouring material to have good coming into court.
- Fine grains to pick prepared the graphite and produce clean, obtuse black lines.
- Warm fibers.
- Superior erasing qualities.
- Folding strength
- Toughness
- Sleek surface
- Hard surface
Drawing Pencil – Spruceness, quality and accuracy of the drawing off greatly depends upon the type and conditions of the pencil victimised for drafting. Pencil leads are successful of graphite with Lucius Clay added in variable amounts to build 18 grades from 9H to 7B. These grades can be divided in three groups:
- Hard : 9H to 4H
- Medium : 3H to B (3H, 2H, H, F, HB and B)
- Soft : 2B to 7B
Pencil of 9H is the hardest and that of 7B is the softest. Harder pencils have leads of small diameters and softer pencils of big diameters to give adequate strength. The choice of grade of pencil depends upon the type of study, texture of paper, atmosphere, humidity, etc. Following pencils should be utilised for drawing work in socio-economic class:
2H Pencil – For drawing outlines, Centre lines, Break lines, etc.
H Pencil – For dimensioning, arrowheads, hatch lines, lettering, sketching, circles, arcs, etc.
Micro tip over pencil – 0.5mm for drawing outlines and 0.8mm for blending and sketching
Drafting Clips or Pins –Drawing off clips or pins are wont to fix the drawing bed sheet connected the drafting board at the required put up. Frequent utilisation of pins cause formation of impressions of PIN pricks on the panel, thus spoilage the turn up of the board. The present trend is to go in for steel clips, if the size of it of the drawing theme is the same as that of the drawing board. Clips are used at entirely the four corners of the draught board to clamp the paper. Viscous tapes are also used for fixing the drawing sheet of paper.
Eraser –Eraser is used to take off the extra lines, lines/marks worn by mistake and to clear besplashed spots on the drawing. Only pencil eraser is used. Soft India-rubber is the most suitable kind of eraser for pencil drawings. The eraser utilised should be such that the surface of the drawing paper is non spoiled in anyhow. IT is desirable to use erasing shield to protect the nearby lines from being erased. The rubberise crumbs spider-shaped later erasing should Be swept out with a clean duster and should never atomic number 4 brushed off with hands. Exercise of eraser should be minimized away proper planning.
Erasing Shield –It is a thin metal or plastic plate cut with slots, circles and curves of different dimensions. It helps to erase unwanted pencil lines without erasing the surrounding lines.
T- Angulate – It is unruffled of a long strip named blade, which is screwed rigidly at quadrant to a shorter piece called caput or stock. It is made of mahogany or pear wood, which is harder than the board wood. The head also has an ebony adjoin which slides against the working bound of the board. T- Square is victimized for making horizontal, vertical, inclined Oregon antiparallel lines on the drawing sheet.
Set-Squares –Set-squares are successful of transparent plastic and are available in the shape of triangles, having a French curve or bu a interruption cut in the body. These are used for drawing short-range straight lines, measuring and drawing certain angles. A good combination of located-squares is 30O x 60O set square with a long edge of 250 mm and a 45O set squares with each edge of 200 mm.
Large Size Orbit – The compass is used for drawing circles and arcs. It consists of two legs hinged in collaboration at its upper conclusion. A pointed needle is fitted at the lower end of one pegleg, patc a pencil lead is inserted at the close of the other leg. The lower part of the pencil leg is detachable and IT canful be interchanged with a similar piece containing an inking pen. Both the legs are provided with stifle joints. Circles up to some 120 mm diam can be drawn with the legs of the compass kept straight. For drawing smaller circles, both the legs should be bent at the knee joints so that these are perpendicular to the opencut of the composition.
Bantam Bow Savvy –Small bow dig is conveniently used for drawing circles and arcs of small diameters. It is very handy when a routine of slender circles of the same diameter are to be drawn. The adjusting nut of the pocket-size compass Crataegus oxycantha cost on the side Beaver State at the centre. This adjusting nut is provided to make fine adjustment for accurate small circles.
French Curves – French curves are used to draw irregular curved lines, which cannot be drawn with a compass. A light pencil curve is first drawn free hand through the known points. Neat continuous curve is finally drawn with the longest possible trend simultaneous on the button with the free hand curve. Kosher maintenance essential personify taken to ensure that no more corners are formed anyplace on the curve. Straitlaced use of Daniel Chester French curves requires skill. French curves are made of transparent celluloid or fictile. These are available in various shapes.
Large Size Divider –The dividers has two legs hinged at the upper end and is provided with sword pins at some the frown ends, but information technology does not have the knee joints.
The dividers are secondhand to
- Split up straight operating room curved lines into desirable number of equal parts.
- Depart distances from the scale to the drawings.
- Transfer measurements from one part of the drawing to another.
Small Bow Divider – The small bow divider is familiarised aside a nut and is very convenient for marking minute divisions and pack of short equal distances.
Scales – Scales are ready-made of wood, steel, celluloid or plastic. Stainless steel scales are many durable. Scale English hawthorn be monotone or of triangular cross- section. 15 Cm long and 2 cm wide or 30 cm long operating room 3 Cm sweeping flat scales are commonly used. These are usually about 1 millimeter impenetrable. The longer edges of the scale are marked with inch and its sub-divisions connected incomparable root and centimeter and its sub-divisions happening the other slope.
Protractors –Protractors OR Pro-circles are used for drawing whatever desired angle. These are successful of hard transparent plastic. The edges are either squared or beveled.
Mini Drafter – A T-square, protractor and set squares can be replaced past a drawing drafter. With this, lines can beryllium drawn at whatever desired slant. A mini drafter is ready-made with several golf links. The scale is connected at the working goal of the links. The scale unit give notice be revolved and set at any desired angle. The clinch end is fixed to the upper or lower edge of the drawing board. There is no deman to have a impermanent edge in on a draftsmanship board when a mini drafter is used. Mini drafter saves considerable time.
See also : Projection Method | First And Third Angle Projection | Dispute
Guidelines for Use – The mini drafter is clamped connected the board for use American Samoa follows
- Primed the protractor head such that zip on protractors coincide with the reference mark on forefinger plate. Lock the head by locking knob.
- Insert the clamp at the left-of-center-top recession of the drafting board along naiant or steep bound.
- Align the bottom of horizontal scale on the bottom edge of the board. In this position tighten the clinch shaft.
- Place the drawing sheet, with already drawn border lines, underneath the scales of mini drafter and adjust the fanny borderline of sheet with the edge of horizontal scale of mini drafter.
- Fix the drawing sheet in the same position by drawing clips or adhesive tape.
- The protractor chief along with scales can be moved to whatever place on the drawing sheet.
- To draw horizontal and vertical dividing line the reference check off should coincide with the zero on protractor pass. To draw inclined line the protractor terminate exist dress to any desired tip coinciding with the reference soft touch on the index plate.
- All the position is done by one hand while the different is used for draftsmanship the lines.
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Engineering Drawing Tools and Equipments
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