A Teacher's Journey: Technical lettering

Technical Lettering

Syllabus:

1. Introduction to lettering and its necessity. Demonstrate the construction details of English alphabets and numerals in 7:4 ratio and free hand in parallel lines

2. Sheet no.3 practice of single stroke vertical English alphabets and numerals (0-9) – uppercase letters (Height14mm and 20mm lettering in 7:4 ratio) in single stroke

Sheet no.4 practice of single stroke inclined English alphabets and numerals (0-9) – uppercase letters (Height14mm and 20mm lettering in 7:4 ratio)

INTRODUCTION

https://youtu.be/bsutdDrPrKw

Technical Lettering is a barren piece of engineering drawing. It gives data concerning measures, and guidelines, as notes and measurements. On a drawing, the entire of the composed data is consistently through lettering. It isn't manually written. Likewise, it very well might be added here, that Lettering is fitting and right words however not (Printing implies the creation of literature on a print machine)

· Lettering

The writing of alphabets and numerals such as A, B, C, D…………………….Z and 1, 2, 3……………9, 0 respectively is called Lettering.

Mainly, there are two types of lettering most commonly used in engineering drawing viz. Gothic Lettering and Roman Lettering.

Single Stroke Letters

Single stroke letters are simplest form of letters and are used to write titles, dimensions, notes and other information on a drawing. Lettering using single stroke letters has been recommended by Bureau of Indian Standards (BIS) and described in IS:9609-1990. The word “single stroke” indicates that the thickness of lines used in letters should be such as obtained in single stroke of pencil. It does not mean that letter written in single stroke without lifting the pencil. The single stroke letters may be of two types e.g., vertical and inclined letters.
The vertical letters are used for general purpose lettering in engineering drawing. Height to width ratio of such letters varies. But for all practical purposes the letters with height to width ratio may be taken as 7:5 or 6:5 for all capital letters except I, J, L, M and W. For M and W the suitable ratio is 10:8 and for I, this ratio is taken as 10:2. For numerals such ratio may be taken as 7:4 or 6:3. Single stroke vertical upper and lower case letters and numerals are shown in Fig. 1.17. The inclined/italics letters are written

at an angle of 75o from horizontal towards right. Fig illustrates typical inclined

letters and numerals. The size of letters and numerals is specified by their heights ‘h’. The

standard heights of letters and numerals for practical use are 1.8, 2.5, 3.5, 5.7, 10, 14 and

20 mm as recommended by BIS. The letters size 5 mm-10 mm may be used for main title

of drawing. For sub-titles, letter size of 3.5 mm or 5 mm may be used conveniently. The

letters and numerals having size 2.5, 3.5 or 5 mm are suitable for writing notes,

dimensions etc. The single stroke letters may be of A type or B type. In A type letter,

height of letter is divided into fourteen parts whereas in B type letter, the height is divided

into 10 parts. The recommended ratio, spacing between letters and thickness of lines

(stems) of letters are summarized in Table and are explained in Fig

Gothic Letters

When the stem of letters are given more thickness, such letters are called as gothic letters.These letters are used for writing the main title for ink drawing. Thickness of stem maybe taken as 1/5th to 1/10th of the height of letters.

General Rules for Lettering

(a) Select the size of letters suitable to given drawing.

(b) Draw horizontal guide lines keeping the distance between them equal to the

height of letters.

lettering with the standard dimensions.

(d) Do not erase the guide lines.

· Height Of Lettering

The height "h" of the capital letter is taken as the base of dimensioning.
The main requirement of lettering on engineering drawing are legibility, uniformity, ease and rapidity in execution.
Both upright and inclined letter are suitable for general use. All letters should be capital, except where lower case letters are accepted internationally for abbreviations.
The recommended size of lettering is as under :-

ITEM	SIZE h, mm
Drawing number in Title Block and letters denoting Cutting Plane Section	10, 12
Title of Drawing	6, 8
Sub-titles and Headings	3, 4, 5, 6,
Notes, such as Legends, Schedules, Material list, Dimensioning	3, 4, 5
Alteration, Enteries and Tolerances	2, 3

· Guide Lines

The light thin lines drawn to obtain uniform and correct height of letters are called Guide Lines.
Guide line should be drawn very light and thin, so that, they need not be erased after the lettering is finished. To erase guide lines after finishing the lettering is not easily possible. Guide line for capital and lower case lettering

· How To Draw Graph For Lettering

The letters are drawn in a graph. Before drawing the alphabets or numerals of 7:4, 5:4 or any other ratio, a graph is needed.

· First of all take the height of the lettering and draw two parallel horizontal lines.

· Draw an inclined line at A and mark, 7 or 5 or as required number of vertical squares or rhombii, parts of any suitable size. Join B1 with B.

· Draw parallel line to B1B from 1, 2, 3, 4, 5, 6 meeting the line AB at A1, A2, A3, A4, A5 and A6.

· From A1, A2, A3, A4, A5 and A6 draw horizontal line.

· From point B draw line at 45' to the horizontal.

Draw the vertical line for making lines for making squares and inclined line at an angle of 75' for making graph for inclined letters.

Problems For Practice SHEET NO: 3

1. Rewrite the following in vertical up right printing. Take height of letters = 10 mm. "GROW MORE FOOD"

2. Rewrite in inclined lettering technique 10 mm height in capital letters the following :- DIFFERENT MATERIALS SHOULD BE INDICATED BY NOTES ON DRAWING

3. Write your name and the name of your institution in single stroke vertical lettering, taking height of letters as 3 mm, 5 mm, 8 mm, 10 mm and 12 mm.

4. Rewrite the following in free hand vertical upright and inclined lettering. I AM PROUD OF MY COUNTRY, take height of letters = 3 mm,4 mm,6 mm, 8 mm and 12 mm.

5. Draw single stroke vertical capital letters of ratio 7 : 4 and 6 : 5, INDIAN STANDARD INSTITUTIONS.

6. Print the single stroke vertical letters in height 28 mm in 7 : 4 ratio, BUY NATIONAL SAVING CERTIFICATES.

7.Draw freehand sketch &write short notes on the following images in lowercase alphabets.

(a) Hexagonal nut

(b) Wing nut

(c) Spur gear