# ENGINEERING GRAPHICS BOOK CLASS 11

In this textbook of Engineering Graphics for class XI, students will learn about Plane Geometry, Solid Geometry and Machine Drawing, which includes. Engineering Graphics Class bestthing.info: V.P. Kumar: Books. (Download) CBSE Text Books: Engineering Graphics (Class XI). https://lh5. bestthing.info

Home» E-Books» NCERT» Class 11» Engineering Graphics ebook for class 11, CBSE, NCERT. Engineering Graphics ebook for class CBSE Class 11 Engineering Graphics Lines, Angles. Students can download the specific chapters from the CBSE and NCERT text books from bestthing.info CBSE Class 11 Engineering Graphics Development of Surfaces. Students can download the specific chapters from the CBSE and NCERT text books from.

Without neat conventional letters and figures a drawing is offensive to a trained eye. We can divide the letters broadly in two types. We can also say Capital and Small letters. Similarly, the ratio of height and width bears some ratio. Generally it is 7: It is not always necessary to adhere to these ratios. According to the space available the letters can be expanded or compressed. The writing of these letters may also vary from person to person.

The letters are written either by free hand or with the help of Stencils. Thus, we can say that process of writing the capital alphabets A, B, C, D, Z , small alphabets a, b, c, d, Now, we shall learn about the correct formation of letters as are printed on the Engineering Graphics.

We shall also learn about the correct ratio between height and width of these letters.

Now, let us learn about the Capital and Small letters along with the Numerals. Before writing these letters we should be familiar with the height, width and shape of these letters as used on the drawing. For main title we take height of main title as 6 mm, for sub title height may be 4 mm and for any other title or dimension it can be 2 mm.

Generally, we use single stroke letters.

## Engineering Graphics ebook for class 11, CBSE, NCERT

The word single stroke should not be taken to mean that the letter should be made in one stroke without lifting the pencil.

It actually means that the thickness of the line of the letter should be such as is obtained in one stroke of the pencil. It is an enough proof that single stroke gothic letters are very simple to write. These basic strokes are as given below: The vertical letters look beautiful and easy to read.

Therefore, we shall learn more about these letters here, later you can go for slanting letters also. Slanting letters are written in the same fashion as the vertical letters, the only difference is the angle of slant, which is These slanting letters are also called italics letters.

For writing Capital or Upper Case Letters divide the height into two equal halves and then write the required letters keeping in mind the ratio of width to the height. Before printing these alphabets, it will be of much use if we draw guide lines. For printing capital letters mainly two guide lines are drawn.

The lower line is called base line and the upper line is called the Cap line or Capital line. It will be much easier for us if a middle line is also drawn for our convenience.

## CBSE Engineering Graphics- A Textbook for Engineering Drawing for Class 11

In the construction of letters, the well known optical illusion in which a horizontal line drawn across the middle of a rectangle appears to be below the middle must be provided for. In order to give the appearance of stability, such letters as B, E, K, S, X, and Z and the figures 3 and 8 must be drawn smaller at the top than the bottom. To see the effect of this illusion turn a printed page upside down and notice the appearance of the letters mentioned.

It will be interesting to note that these strokes are drawn from top to bottom and from left to right. It is also very important to note that the first requirement in lettering is to hold the pencil correctly. The pencil should be held comfortably with the thumb, forefinger and second finger on alternate flat sides and third and fourth fingers on the paper.

Vertical slanting and curved strokes are drawn with a steady, even, finger movement; horizontal strokes are made similarly but with some pivoting of the hand at the wrist. Exert pressure, which is firm and uniform but not so heavy as to cut grooves in the paper. To keep the point symmetrical, form the habit of rotating the pencil after every few strokes.

Six Fundamental Stroke Fig. Study the shape of each letter, with the order and direction of the strokes forming it and practice it until its form and construction are familiar to you.

Let us first take I, H, and T group: The letter I is the foundation stroke. We shall find it difficult to keep the stems strokes vertical. If so draw direction lines lightly. The H is nearly rectangular and the cross bar is just in centre. The top of T is drawn first to the full width and then the stem is drawn in the middle vertically.

The letter L is made in two strokes The first two strokes of E are the same as for the letter L and the third or upper stroke is slightly shorter than the lowest stroke or may be drawn equal.

The third stroke will be two third of the longest stroke and drawn in the middle of the letter. The letter F has the same proportions as for the letter E except the lowest line. For drawing letter N the parallel sides are drawn first and then the slanting line is drawn. For the letter Z top and bottom horizontal lines are drawn first and then the slanting line is drawn. For writing Y, draw half X and the junction of the Y stroke is at the centre. V is of the same width as A. The A bridge is one third up from the bottom.

The second stroke of K strikes the stem one third up from the bottom, the third stroke branches from it in a direction starting from top of the stem. These two letters are the widest of all letters. M may be made in consecutive strokes or by drawing the two vertical strokes first, as with the M, W is formed of two narrow Vs, each two third in width of the letter. Note that with all the pointed letters the width at the point is the width of the stroke.

In this group letters are mde as full circles. The O is made in two strokes, the left side is a longer arc than the right, as the right side is harder to draw. Make the kern of the Q straight. A large size C and G can be made more accurately with an extra stroke at the top.

Whereas, in smaller letters the curve is made in one stroke. Note that the middle bar in G is halfway up and does not extend past the vertical stroke. Figure 1. The top and bottom strokes of D must be horizontal.

Failure to observe this is a common fault with the beginners. Letter U is formed by two parallel strokes to which the bottom stroke is added, in smaller letters it may be made in two strokes curved to meet at the bottom. J has the same construction as U with the first stroke omitted. With P, R and B the number of strokes depends upon the size of the letter. For capital letters the horizontal lines are drawn and the curves added, but for smaller letters only one stroke for each to be added.

The middle line of P and R are on the centre line. For B observe the rule of stability. This group is closely related in form. The rule of stability may be observed carefully. For capital S, three strokes are used, for a smaller one, two strokes and for a very small size one stroke only is best. The 8 and S are similar in construction.

These letters are made in three strokes. Or in head and body in four strokes. A perfect 3 can be finished in 8. The numeral O is five-sixth the width of the letter, is an ellipse. The backbones of 6 and 9 have the same curve as of 0 and the lobes are slightly less than two-thirds the height of the letter.

The secret in making the 2 lies in getting the reverse curve to cross the centre of the space. The bottom of 2 and the top of 5 and 7 should be horizontal ; straight lines. The second stroke of 7 terminates directly below the middle of the top stroke. Its stiffness is relieved by curving it slightly at the lower end.

For standard letters, the waist-line height is two-thirds of capital height; capital Line and drop line are therefore one-third above and one-third below the body of the letter. Note that the center lines of the letters follow the slope angle. Note the graceful combination of elliptical body, ascenders and descenders.

The basic shape is elliptical.

They are combinations of ellipses and straight lines. Their formation is basically elliptical. The principal reason that left hander sometimes find lettering difficult is that whereas the right hander progresses away from the body, the left hander progresses toward the bodyconsequently, the pencil and hand partially hide the work done making it harder to join strokes and to preserve uniformity. For the natural left hander, whose writing position is the same as a right hander except reversed left for right, a change in the sequence of strokes of some of the letters will obviate part of the difficulty caused by interference with the line of sight.

For example for letter E the top bar is made before the bottom bar and M is drawn from left to right to avoid having strokes hidden by the pencil. Horizontal portions of curves are easier to make from right to left, hence the starting points for O, Q, C, G and U differ from the standard right hand stroking.

S is the perfect letter for the left hander and is best made in single smooth stroke. The figures 6 and 9 are difficult and require extra practice. In lower case letters a, d, g and q it is better to draw the straight line before the curve, even though it makes spacing a little hurdle.

Acquire a thorough knowledge of all types of letters, the general shape, proportion and design and direction of the strokes used to produce it. Learn to compose letter in formation of words and see that spacing is proper and uniform.

Practice consistently and conscientiously. Lettering for titles and sub-titles should be written in guided lines. These letters should be written by a single stroke of pencil and no sketching is done. All letters should be uniform in shape, size, stroke, shade and spacing. The shine and boldness of the letters and numerals should be the same. The letters should be legible and uniform in height and width, except for the letters I, J M and W.

The letters can be written in the expanded or compressed form according to the space available for writing. The space between two letters must be kept uniform and a gap equal to twice the thickness of the letter may be kept between two except when writing: Similarly, no gap is to be given while writing: The space between two words may be equal to the width of one letter. The line thickness for small and cepital alphabets shall be the same.

The guide lines should be drawn with 4H Thin lines and unnecessary lines may be rubbed off. Write in capital letters on your notebook the following things: Write the following paragraph in Capital and Small letters: Your application for a job is your ambassador.

It reaches before you reach a firm for a job. It discloses everything about your personality. Therefore, always write in a good hand. How many types of letters are there? What do you understand by letter printing? Write the following sentence into Capital and small letters: Engineering Graphics is the language of Engineers. Write the following letters and numerals in the single stroke gothic letters: The height of main title may be taken as 6 mm, subtitles as 4 mm and any other title or dimension in 2 mm.

Write the name of guide lines as used for capital letters and for small letters. What points should be kept in mind while writing single stroke gothic letters? How we can write beautiful and legible letters? What is the ratio of height and width in capital letters? What is the ratio between height and width of small letters?

How we should divide the height for small letters?

How much gap between two letters and two words may be given? Explain the rule of spacing between the letters. Write in capital and small letters the following lines: The letters and numerals are written with a conical blunt pencil, these consist of horizontal, vertical, inclined and curved strokes to give the required letters. A carpenter uses different types of wood and tools to make furniture etc. Similarly, Engineers use different materials and tools for drawing Engg. A person generating a drawing needs particular type of materials and equipments to draw drawing neatly, conveniently and with less labour.

Thus, he saves a lot of energy and time. The quality of drawing produced is also of good quality. These instruments and material may be downloadd under the guidance of your Engineering Graphics teacher or from, a standard stationery shop to ensure quality and usefulness.

List of Materials and Equipments required at this stage of learning. Drawing Board of half imperial size. Drawing sheets of imperial size and of good quality.

These can be cut into half imperial size by thread or a paper cutter. Imperial size Sketch Book. HB, 2H and 4H, later a single mechanical pencil using leads of 0. A non-dust rubber of good quality. Scales of mm and mm. Two compasses with the facility of bending arms. One compass for holding B and other for 2H pencil leads. One divider with needles at two ends. Set squares having angles of 45, 90 and 45 of mm in length length of hypotenuse and 30, 90 amd 60 of mm in length, made up of good quality cellouse.

Drawing board clamps, clips, pins or cello tape for fixing the drawing sheet. One protector of semicircular shape of 50 mm radius made of plastic. A piece of 0 sand paper or a fine file or emery paper for sharpening the pencil lead.

A pencil cutter, sharpener or pencil machine cutter. A small paper knife or some stitching thread to cut the drawing sheets etc. A handkerchief or clean duster or a clean hand Towel to clean the instruments or remove dust from the drawing sheet or for removing the rubber dust.

Pencil leads of B and 2H for fixing in the compasses. Drawing file of half imperial size or a round plastic box or a shuttle cock box for keeping drawing sheets. A small circle plate or circle master for drawing curves and small circles. Tee-Square, Roller drafter or a Mini-Drafter for using on a half imperial size drawing board.

These wooden strips are cleated at the bottom and two rectangular wooden battens are screwed to check wrapping. A working edge made of ebony wood is provided on the left edge of the board. The T-square slides along this edge. For more smoothness of the working surface of the drawing board may be laminated.

Generally a half imperial size drawing sheet is enough to be used at this stage. The half imperial size of drawing sheet is mm mm in size. White sheets are used where the appearance is given more consideration.

The drawing sheet has two sides one is rough side and the other is smooth side. We generally use rough side so that pencil may give good impression. The drawing sheet should possess the uniform thickness and of such a quality that the erasing effect should not be there.

The class notes of Graphics may be made in this Sketch Book. It will be much useful at the time of examination as we have not to look in other note books about the important Graphics or notes etc. On the more, this note book keep a tab on what we have learnt in the class or elsewhere. It will be much better if all the pencils are of the same manufacturer. We have noticed that at one end of the pencil HB, 2H or any other number is written.

We should know that the numeral denotes the degree of softness or hardness. H stands for hardness and B for blackness. Thus HB stands for hard black pencil. These pencils are available from 9H to 7B grades. There are two medium grade pencil HB and F also available in the market. These pencils are sharpened in the Conical or Chisel shape according to the necessity of the drawing. For us a good quality soft rubber will serve the purpose. Excessive pressure should not be applied to the eraser to prevent the damage of the drawing.

Care should be taken to hold the erasing shield tightly to prevent it from slipping. These are transparent and scales of mm and mm in length are enough. These are used for measuring sizes, lengths as the relative dimensions of the object are transferred to the drawing. Some compasses have detachable pencil and ink point. The needle and lead legs have knee joints from where the legs can be bent. For drawing large arcs or circles the legs are bent about the knee joint in such a way that their lower limbs are perpendicular to the drawing board or drawing sheet.

Leads of 2H and B are fixed in two different compasses for use for drawing light and bold lines. One thing is very important for drawing a good arc or circle is that the pencil lead to give a margin for needle which pricks the sheet a little bit.

A lead of one grade softer may be used in the compass just for compensating the pressure on the pencil while drawing a straight line. Point Lengths Slight angle B. Sharpen on outside Sandpaper Slight angle C. Bevel Point Fig. It is used to draw small arcs and circles. It is suitable for drawing circles or arcs from 2 mm to 60 mm diameter. Open the legs of compass and measure the radius of the arc or circle from the scale. Place the needle at the exact intersection of the centre lines and prick the drawing sheet by the needle.

Rotate the compass in the clockwise direction such that the pencil lead touches the drawing sheet. Draw a crisp arc or required circle. We have to keep in mind that the thickness and darkness of line should be uniform throughout your drawing. Two needles are there at two ends of legs. It is used to divide a length into any number of equal parts. It is used to transfer the distance from one place to another on the drawing sheet.

Bow Divider: It is used for dividing small circles or arcs or a line segment into number of equal distances. Small set squares may be preferred over large ones for using with mini-drafter. The set-squares are used to draw vertical or parallel lines along with the use of mini- drafter.

A pair of set-squares can be used to draw angles of 15, 30, 45, 60, 75, 90, , , , , and See Fig. These clamps, pins, cello tape etc, is used to hold the drawing sheet on the drawing board. It is semi circular in shape and made up of cellouse. It is a good choice to draw angles correct up to one degree.

A protractor can be read from both the ends. The circumferential edge of a protractor is graduated to or 1 division, which is numbered at every 10 intervals. A precuation may be taken that the lead powder does not fall on the drawing sheet and spoil the drawing. Similarly, lead powder should be cleaned from hands also before commencing the preparation of drawing sheet.

These precautions are very necessary to be kept in mind to save the drawing sheet from smudging. The only advantage is that it does not break the lead and wooden peeling are collected in a box below the machine.

Thus keeping the place clean. It will prevent drawing from smudging. These leads are needed to be fixed in the compasses. If the leads are not available in the market then the same may be obtained from the pencils of the required grade by peeling the pencils.

It is used to draw circles of small diameters easily and cleanly. The circles of standard diameters are also drawn quickly, uniformly and cleanly. As the name itself suggest that it is made in a T form. A thick wood or plastic butt is fitted on one end and a long wooden or plastic blade on the other.

It is used to draw horizontal lines and also for supporting the set squares for drawing vertical or parallel lines on the drawing sheets.

With its help parallel lines at any angle can be drawn along with horizontal and vertical lines. It can be said that it is all in one. It is very convenient to carry and use.

Thus, it is gaining popularity with Engineers and architects. These scales are tightened with a screw at any inclination, generally parallel with the drawing boards edges.

The set squares slide on these right angled scales for drawing parallel or inclined lines. It obviates the use of a separate Tee- square, protractor, set-squares and scale.

Thus, saving a lot of energy and time in drawing good graphics. Always keep in mind that the zero of the adjustable circular disc marking should coincide when its scales are in horizontal and vertical position. The fixed end should tightly fit with the edge of the drawing board and should not move with the movements of the scales.

Always clean your hands and instruments before fixing the drawing sheet. Hands should be frequently wiped with clean handkerchief or with a clean piece of cloth during the drawing work.

The set squares may be lightly moved with the finger nails while using. Clean pencil smudge with a clean cloth 5. The rubbed powder of pencil is removed away from drawing sheet just to save the drawing from smudging. Drawing sheet should be erased with a soft rubber only when it is very necessary to rub off the extra lines. Remove rubber dust with a clean piece of cloth or with a clean handkerchief, never wipe them off with hands.

A clean piece of cloth or paper may be used as a hand rest, while printing or lettering. Do not keep anything or article on the drawing sheet especially utencils or containers etc.

While not using the drawing sheet, may be covered with a cotton cloth or wide paper. Avoid unnecessary rubbing of lines. Do not touch drawing sheet with direct hand. For getting good results from your drawing board, cover it with a drawing sheet or with a thick sheet of paper.

Use cello tape or drawing pins to fix it on the drawing board. By doing this we avoid the drawing pencil to move in the drawing boards wooden grooves and will give smooth lines. Now with the help of protractor draw angles of 72 at both the ends. Construct a regular hexagon of 60 mm side with the help of set squares. Try the same activity with the help of a divider also. Why drawing instruments are needed for drawing? What is a mini drafter?

Write the important drawing instruments and their uses in drawing? What precautions may be taken for drawing a clean and neat drawing? What are the common grades of pencil available in the market? What do the letters on them indicate?

What we mean by H, HB or B pencil? What angles can be drawn with a pair of set-squares? What grade of pencil may be used in compass for a particular grade used for drawing straight line to get the same shine and brightness? How parallel lines can be drawn with a pair of set squares? Draw parallel lines at a distance of 25 mm.

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Where a divider is used? Fill in the blanks with appropriate words: Match the following from the list A with B. Table - A Table - B a Straight lines can be drawn with its help a Using a scale b The two parts of the Tee-square are b Using a divider c The distance are measured in millimeters by c Butt and blade d Lines of different thickness are drawn by using d Set squares e Equal distances can be drawn on the drawing sheet by e Pencils f For measuring any angle we use f Protractor g We can draw angles in multiple of 15 with this g Tee-square Answer a g b c c a d e e b f f g d 43 Lines, Angles, Letters, Dimensioning and Rectiliner Figures 1.

These are either readymade or specially stitched by a tailor for us. When we visit a tailor shop for getting our clothes stitched. The tailor measures our cloth with a measuring cloth tape and also takes our body measurements. After few days, he delivers our stitched clothes, which are fully made according to our need and body measurements. Nowadays, we also see that new buildings are coming up but they are made up to a specific height.

These buildings are made on an alloted piece of land. Rooms, shops furniture and engineering products are made according to some map, which is nothing but a blue print of a future structure made according to some measurements. Dimensioning is a must for the technician who is making it. Similarly, all things are produced by some measurements according to the need and purpose. This measurement is done according to some system.

In most of the countries the Metric System of measurements is used.

## Engineering Graphics

But in some countries FPS System is followed. So, it becomes very necessary for us to know about the conversion of one unit in to another. We know very well that when we have to get anything made according to our need we have to give some specific dimensions to suit our need. Similarly, drawings are exchanged from one country to another or we can say that sometime the drawing is made in one country and the product is manufactured in another country. This makes it a necessity to specify the dimensions on the drewing.

Thus we can say that dimensiong is a numerical value expressed in appropriate units here it is millimeters of measurement and indicated graphically on technical drawings with lines, symbols and notes.

These include projection lines, Dimension lines, leader lines, dimension line termination, the origin indication and the dimension itself. These are thin continuous thin lines.

These are terminated by arrowheads touching the outlines, extension lines or centre lines. A leader or a pointer is a thin continuous line, connecting a note or a dimension figure with the feature to which it applies. One end of the leader terminates either in an arrowhead or a dot. The arrowhead touches the outline, while the dot is placed within the outline of the object. The other end of the leader line is terminated in a horizontal line at the bottom level of the first or the last letter of the note.

The leader is never drawn vertical or horizontal or curved. It is drawn at a convenient angle of not less than 30 to a line to which it touches. When pointing to a circle or an arc it is drawn radially. Use of common leader line for more than one feature should never be made. These lines are thin continous lines drawn in extension of an outline. These lines extend by about 3 mm beyond the dimension line.

There are various type of arrow heads. The pointed end of the arrowhead should touch an outline or an extension line or a centre line. It is drawn free hand with two strokes made in the direction of its pointed end.

There are two types of dimensions one is size dimensions and another is location dimensions. It is shown in this figure. Some examples are given in Figure 1. The above indications are used with dimensions to show applicable shape identification and to improve drawing interpretation. The diameter and square symbols may be omitted where the shape is clearly indicated.

The applicable symbol precedes the value for the dimension. To show radius of a circle or an arc R 2. To show diameter of a circle 3.

To show a square or sq. In this chains of single dimension are done as shown in Fig. Dimension are given from a common origin as shown in Fig. It is the placement of a number of single dimension lines parallel to one another and spaced out so that the dimensional value can easily be added in Fig.

It is simplified parallel dimensioning and may be used where there are space limitations and where legibility problems would occur. In this system the combination of chain dimensioning and parallel dimensioning are used together. In this arrangement, one datum point is selected which reads as zero: According to this system all dimensions are so placed so that they may be read from the bottom of the drawing and vertical dimensions from the right hand side.

The dimensions values should be placed parallel to their dimension lines and preferably near the middle and above and clear of the dimension line.

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This system is generally used for small drawings. In this system all dimensions are so placed in such a way that they may be read from bottom of the sheet. This system is useful for large drawings. Then dimension line is drawn parallel to the outline to be dimensioned which is terminated by arrow heads at the ends. The numerical value is written in the middle at right angle above the dimension line with a dark pencil. Also the dimension lines or numerals should not be drawn for written too close.

They can be staggered, if many dimensions lie near to each other. The dimension for an inclined line may be written parallel to it, to make it legible. Arabic Sub: Beauty and Hair Class: Fashion Studies. Beverage Service Practical Manual Class: Beverage Service Text Book Class: Biotech Book Class: Bakery - I Class: Basic Horticulture-I Class: SH - XI Lang: Basic Pattern Development Class: Basis of front office student mannuals Folder Class: Office Management.

Computer Science Class: Disaster Management in English Class: Social Science. It will be interesting to note that these strokes are drawn from top to bottom and from left to right. It is also very important to note that the first requirement in lettering is to hold the pencil correctly. The pencil should be held comfortably with the thumb, forefinger and second finger on alternate flat sides and third and fourth fingers on the paper.

Vertical slanting and curved strokes are drawn with a steady, even, finger movement; horizontal strokes are made similarly but with some pivoting of the hand at the wrist. Exert pressure, which is firm and uniform but not so heavy as to cut grooves in the paper.

To keep the point symmetrical, form the habit of rotating the pencil after every few strokes. Study the shape of each letter, with the order and direction of the strokes forming it and practice it until its form and construction are familiar to you.

We shall find it difficult to keep the stems strokes vertical. If so draw direction lines lightly. The H is nearly rectangular and the cross bar is just in centre. The top of T is drawn first to the full width and then the stem is drawn in the middle vertically. The third stroke will be two third of the longest stroke and drawn in the middle of the letter. The letter F has the same proportions as for the letter E except the lowest line.

For the letter Z top and bottom horizontal lines are drawn first and then the slanting line is drawn. For writing Y, draw half X and the junction of the Y stroke is at the centre. The A bridge is one third up from the bottom. The second stroke of K strikes the stem one third up from the bottom, the third stroke branches from it in a direction starting from top of the stem.

M may be made in consecutive strokes or by drawing the two vertical strokes first, as with the M, W is formed of two narrow Vs, each two third in width of the letter.

Note that with all the pointed letters the width at the point is the width of the stroke. The O is made in two strokes, the left side is a longer arc than the right, as the right side is harder to draw. Make the kern of the Q straight. A large size C and G can be made more accurately with an extra stroke at the top. Whereas, in smaller letters the curve is made in one stroke.

Note that the middle bar in G is halfway up and does not extend past the vertical stroke.

M and W are wider than the other letters by one unit. Failure to observe this is a common fault with the beginners. Letter U is formed by two parallel strokes to which the bottom stroke is added, in smaller letters it may be made in two strokes curved to meet at the bottom.

J has the same construction as U with the first stroke omitted.Introduction of threads: Standard profiles of screw threads square, knuckle, B. Whereas, in smaller letters the curve is made in one stroke.

The A bridge is one third up from the bottom. Theatre Studies Class: With our earlier knowledge of quadrants, we come to know that space above H. Chain line:

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