All dimensioning system

there all dimension method .to learn

1. Shree S’ad Vidya Mandal Institute Of Technology ENGINEERING GRAPHICS Branch: - Mechanical – 02 Group :- 01 Guided Name:- Topic : - All Dimensioning system. Prepared By : - 1 . DHAVAL S. PATEL. 63 2. DHRUMIL J. PATEL . 64 3. HARSH J. PATEL. 65 4. JAY J. PATEL. 66

2. Aligned System In the aligned system, dimensions are aligned with the entity being measured. They are placed perpendicular to the dimension line such that they may be read from the bottom or right-hand side of the drawing sheet. Dimensions are placed at the middle and on top of the dimension lines. Unidirectional System In the unidirectional system, dimensions are placed in such a way that they can be read from the bottom edge of the drawing sheet. Dimensions are inserted by breaking the dimension lines at the middle. Systems of Dimensioning

3. Dimensioning systems Aligned system (readable from bottom and right edge of sheet) Unidirectional system (visible from bottom edge)

4. Dimensioning Providing information on a drawing about Distances (size or functional dimensions) Sizes and positions (location or datum dimensions) of holes, grooves and other features. Details relating to manufacture etc. 15 15 30 Roughness 0.5 Location Location Size, functional Manufacturing detail Hole f 15 Size specification, f – symbol for diameter

5. Different lines in dimensioning Outline - Forms the shape of the object in a view (drawn dark and continuous) Extension line – An extension of an outline or centerline (drawn light and continuous, used to indicate the entity being dimensioned) Dimension line – Thin continuous line terminated by arrowheads touching the outlines, extension lines or center lines (used to specify end points of a dimension) Outline Extension line 50 Dimension line Dimension

6. Leader lines and notes Hole f 15 Note Leader (or pointer) line – Thin continuous line connecting a note or dimension figure with the feature to which it applies. One end of the leader terminates in an arrowhead or dot. The arrowhead touches the outline while the dot is placed within the object or on the outline The other end of a leader is terminated in a horizontal line underlining the note Leader line Material: mild steel Roughness 0.5 Leader line

7. Arrowheads and dimension line positioning A dimension line is placed at least 6-8 mm away from an outline and from each other An extension line extends ~3mm beyond a dimension line Arrowhead – Placed at each end of a dimension line, its pointed end touches an outline, extension line or a centerline. It is also placed at the end of a leader line ~3mm 50 Arrowhead 45 o Open Closed Closed and filled Oblique stroke w 3w Size of the arrowhead should be proportional to the length of the dimension line ~6-8mm

8. Chain (continuous) dimensioning All the dimensions are aligned in such a way that an arrowhead of one dimension touches tip-to-tip the arrowhead of the adjacent dimension. The overall dimension is placed outside the other smaller dimensions

9. Parallel (progressive) dimensioning All the dimensions are shown from a common reference line. Obviously, all these dimensions share a common extension line. This method is adopted when dimensions have to be established from a particular datum surface Smaller dimensions should always be placed nearer the view. The next smaller dimension should be placed next and so on.

10. Combined dimensioning When both the methods, i.e., chain dimensioning and parallel dimensioning are used on the same drawing, the method of dimensioning is called combined dimensioning 15

11. Circular holes A hole is usually dimensioned by giving its diameter instead of radius . The dimension indicating a diameter should always be preceded by the symbol ø They should be dimensioned in the view in which they appear as circles f 40

12. Placing of dimension Within extension lines Outside extension lines With leader 7 o

13. An arc is usually dimensioned by giving its radius. The dimension indicating radius should be preceded by symbol R The R can be placed after the dimension also The position of center of arc is denoted by a Dimensioning arcs

14. O FOR S.V. FOR F.V. PICTORIAL PRESENTATION IS GIVEN THE ALIGNED SYSTEM ORTHOGRAPHIC PROJECTIONS X Y 40 20 SQ30 20 50 60 30 10 F.V. S.V. FRONT VIEW L.H.SIDE VIEW 75

15. FOR F.V. O PICTORIAL PRESENTATION IS GIVE THE UNIDIRECTIONAL METHOD ORTHOGRAPHIC PROJECTIONS FOR T.V. X Y FV O 40 10 10 TV 25 25 30 R 100 10 10 f 20 f 30