Conventional Practices in Section view drawing

Conventional Practices in Section view drawing

Chapter 10 Conventional Practice in Section View TOPICS Section view representation

of rib, web, spoke and lug. Aligned section Conventional break Section view representation of

rib, web, spoke and lug TERMINOLOGY Rib and Web are thin, flat feature of an object that acts as a structural support.

Rib Rib Web

TERMINOLOGY Spoke is the rod radiating from the hub to the rim of a wheel. Hub Hub

Spoke Rim Rim

Spoke TERMINOLOGY Lug is an ear which is built as portion of an object for attachment.

TERMINOLOGY Lug is an ear which is built as portion of an object for attachment. CONVENTIONAL PRACTICE Omit the section lines on the section view of

Rib, Web and Lug, if the cutting plane is passed flatwise through. Spoke, if the cutting plane is passed longwise through. EXAMPLE : RIB

Normal multiview drawing Normal section view Section view drawing with convention

EXAMPLE : WEB : flatwise cut Normal multiview drawing Normal section view Section view drawing with convention

EXAMPLE : WEB : crosswise cut EXAMPLE : WEB : multiple section view EXAMPLE : SPOKE

Misleading impression EXAMPLE : LUG Aligned Section

DEFINITION Aligned section is a section view that is drawn by imaginary rotating the objects features appeared in a principal view about symmetry axis

Example : Hole Gives the impression that this holes are at unsymmetrical

Example : Hole Example : Rib Example : Ribs & Holes

Example : Aligned section&ofKeyway keyway Example : Spoke

Example : Lug Conventional Break CONVENTIONAL PRACTICE

For long objects that have to draw in a small scale to fit them on the paper, it is recommended to remove its long portion (which contains no important information) and draw the break lines at the broken ends.

Example SCALE 1:1 Example

SCALE 2:1 STANDARD BREAK LINES Wood Rectangular

cross section Cylindrical cross section Tubular cross section

Metal TO DRAW CYLINDRICAL BREAK 30o R

30o R/3 R/3 TO DIMENSION A BROKEN PART 16

Typical dimensioning method 800

16 800 not to scale dimensions

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