2._Drawing_Tools.ppt

Graphics

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Drafting Instruments or Tools

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Standard Sizes (IS 1444:1989)
920 mm x 650 mm
650 mm x 470 mm
500 mm x 350 mm
Thickness –22 mm
Drawing Board

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A drafting machine is used by a professional draftsman to prepare drawings.
A miniature version of the drafting machine is known as “Mini-drafter”.
It combines the functions of T-Square, Set-Squares, Scales, Protractor, and
Clinograph.
Mini Drafter
Clamping screw
Knob
Right angled scales
Double Parallel Bars

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Set the reference mark on the protractor head to read 0and tighten the knob.
Clamp the drafter to the left-side top edge of the drawing board, such that the
horizontal scale is parallel to the horizontal edge of the drawing sheet.
Now, one can draw horizontal and vertical lines.
To draw inclined lines, the scale should be indexed to the required angle.
Mini Drafter -Fixing

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Large compass –to draw circles from 30 mm to 120 mm diameter
Lengthening bar –attachment used to draw circles of more than 125 mm.
Small Bow compass –to draw circle of diameter up to 30 mm.
Dividers (Large and small) –transferring dimensions and dividing lines or
curves into number of equal parts.
Instrument Box

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45and 60-30triangles.
Set Squares & Protractor cum Procircle

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Accuracy and appearance of a drawing depends on the quality of pencil.
The grade of a pencil lead is marked on the pencil.
HB denotes medium grade.
Increase in hardness is shown by value put in front of H such as 2H, 3H etc.,
Softer pencils are marked as 2B, 3B, 4B etc.
Beginning of a drawing may be made with H or 2H.
For lettering and dimensioning, H and HB pencils are used.
Drawing Pencils

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Drawing clips & Adhesive tape
Sharpener
Eraser
French curves
Other Instruments