Chapter 4 Conventional Practice in Section View PDF
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This document explains conventional practices in engineering drawing, specifically focusing on section views and how to represent different features like ribs, webs, spokes, and lugs. It includes examples showcasing various techniques and conventions.
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Chapter 4 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...
Chapter 4 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. Web Rib Rib TERMINOLOGY Spoke is the rod radiating from the hub to the rim of a wheel. Hub Hub Spoke Rim Spoke Rim 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 object’s 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 Example : Spoke : Aligned section&ofKeyway keyway 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 Metal Cylindrical cross section Tubular cross section 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
