Benefits of Drawing Tools

The traditional method of creatingtechnical drawings is with drawinginstruments.

Since the eighteenth century,precision instruments have been the tools of drafters. Today, CAD software is another toolused by many drafters. The basic concepts of drawing and measuring is the same fortraditional and CAD drawing. Byunderstanding the basic principles of drawing,the properly trained drafter can create andmodify any type of drawing. For many years, the essential equipmentfor students in technical schools and forengineers and designers in professionalpractice remained unchanged.

This equipmentincluded a drawing board, T-square, triangles,an architects or engineers scale, and aprofessional-quality set of drawinginstruments. Now, however, other equipmenthas come into general use, including the drafting machine, parallel-ruling straightedge,technical fountain pen and, of course, the computer. Typical pens used for technicaldrawing are pencils and technical pens. Usually used are mechanical pencils with astandard lead thickness.

General line widthsare 0. 18 mm, 0. 25 mm, 0. 5 mm and 0. 7 mm.

Hardness varies usually from HB to 2H.Softerlead gives a better contrast, but harder leadgives more accurate track. Paper or plasticsurfaces do require their own lead types. In most cases, the final drawings aredrawn with ink. The pen is generallyRapidograf-type technical pen, a marker penthat draws lines of consistent width (so-calledsteel marker pen). The pen has an ink container which contains a metal tube, insidewhich is a thin metal needle or wire, the soul.

Ink is absorbed between the needle and thetube wall, preventing an excessive amount of ink from being released.The needle has a weight and by waving the pen back and forththe needle is released and the ink can run. Previously, the tank was filled from an ink bottle, newer styluses use ink cartridges. Eachline width has its own stylus.

Width of the lineis standardized. In Finland, the mostcommonly used set is 0. 13 mm, 0. 18 mm, 0.

25mm, 0. 35 mm, 0. 50 mm and 0. 70 mm.

Thereare their own stylii for tracing paper andplastic, because plastic requires a harder pentip. The drawing board is an essentialtool. Paper will be attached and kept straightand still, so that the drawing can be done withaccuracy.Generally, different kinds of assistance ruler are used in drawing. Thedrawing board is usually mounted to a floorpedestal in which the board turns to a differentposition, and also its height can be adjustable.

Smaller drawing boards are produced fortable-top use. Drafting machine is a device which ismounted to the drawing board. It has rules thatcan be adjusted by controlling mechanism. There are two main types of apparatus: aparallelogram apparatus based on a hingedarm; and a "wagon apparatus" which moves onrails mounted to the top of the drawing board.

The accuracy of the parallelogram apparatus isbetter in the middle of the board, decreasingtowards the edges, whereas a wagon apparatushas a constant accuracy over the whole board. Parallelogram apparatus are often equippedwith a ballast, with the intention to make thedevice lighter to handle. The drawing-head of a wagon apparatus slides on bearings in avertical trail, which in turns is moving along ahorizontal, top-mounted rail. Both apparatustypes do have a movable drawing-head and therules attached to it so that the angle betweenthe rules may be adjusted.Drawing apparatus enables easydrawing of parallel lines over the paper. Theadjustable angle between the rulers lets the lines to be drawn in varying angles.

Rulersmay also be used as a support for separatespecial rulers and letter templates. The rulesare replaceable and they can be for examplescale-rules. Drawing apparatus has evolvedfrom a drawing board mounted parallel rulerand a pantograph, a device copying the ratios. Rulers used in technical drawing areusually made of polystyrene.

Rulers come intwo types according to the design of theiredge.Straight edge can be used with lead andfelt pens, whereas when technical pen is usedthe edge must be grooved to prevent thespread of the ink. The basic tool in technical drawing isa triangular set square, either 90/60/30 or90/45/45 degree. Also in use are acontinuously adjustable 0-90 degreesprotractor and a separate T-square - astraightedge which can use the edge of thedrawing board as a support. Architect's scale is a scaled, three-edged ruler which has six different scalesmarked to its sides. A typical combination forbuildings details is 1:20, 1:50, 1:100, 1:25,1:75 and 1:125.

There are their own rulers forzoning work as well as for inch units. Todayscale rulers are made of plastic, formerly of hardwood. A pocket-sized version is alsoavailable, with scales printed on flexibleplastic stripes. A parallel ruler is a movable rulerused on the drawing board. Its angle staysconstant and with it the horizontal lines can beeasily be drawn all over the board.

It is alsoused as a support for protractor and lettertemplates.The parallel ruler is usuallyconnected to the board with strings, whichallow the ruler to e positioned in a smallangle. For drawing of curves, rulers of various designs are used: solid curved rulers and "parrot rulers" or a curved ruler the shapeof which can be modified. Templates contain pre-dimensionedholes in the right scale to accurately draw asymbol or sign.

Letter templates will deliverthe text, as well number as letter characters. For drawing circles and circle-arcs, circletemplates are used, containing a suitable set of holes in certain dimensions with suitable sizedholes in them.Models are also available forother geometric shapes such as squares and fordrawing ellipses. Drafting paper is silk-like andtranslucent. It is primarily suitable for pencilsand felt tip pens.

Pencil marks can becorrected to some extent with an eraser. Tracing paper is polished sandwich-like sheetwhich is suitable for lead and pens. Eraser orscraping is used for correcting. Translucentplastic films are commonly used inphotocopying. They have higher mechanicalstrength than translucent paper. Drawing inks can be divided into twogroups: soot inks and "plastic inks".

Soot ink suits in drawing to paper and most drawingplastics. The most commonly used black sootink is a colloidal mixture of water and carbonblack. Plastic inks used on polyester sheets arenon-corrosive. Corrosive inks are mainly usedin map drawing.

Draftsmen who practice and learncorrect manipulation of their drawinginstruments should strive to attain accuracy,speed, legibility and neatness. As technicaldrawing requires thought and concentration,mastery of technical drawing tools willpromote efficient and effective drawing.Reference:Technicalhttps://en.wikipedia.org/wiki/Technical_drawing_tool