Conventional Practices At times it is necessary to depart from the exact rules of projections for the sake of increased clarity, or savings in drawing time and effort (without sacrificing clarity of communication). 2
Fillets and Rounds Exterior corners unsafe Exterior corner unpleasant Rounded external corner is called a round 3
Fillets and Rounds High cost of interior corners Weakness in interior corners Rounded internal corner is called a fillet 4
Fillets and Rounds are very common because of the requirements of manufacturing processes. It is very difficult to get sharp corners in components made by forging, casting, or bending of sheets. 5
This corner not rounded because the base of the bracket must be milled flat to sit on a mating surface Fillet . . Round 6
Rounded internal corners do not project properly 7
All rounded corners formed by unfinished surfaces are shown broken. 8
True projection Add line to show change of direction No line- poor practice From rounded corners 9
10
Conventional Practices: Run-outs 11
Run-outs Note: The Indian standards define this convention for the threaded hole 12
Run-outs 13
Conventional Practices: Run Outs for Intersecting Fillets and Rounds 14
Unnecessary details 15
Conventional Practices: 16
But do not conventionalize everywhere Difference between true and conventional is far too great 17
Unnecessary details 18
Conventional Practices: 19
But do not conventionalize everywhere Difference between true and conventional is far too great 20
But do not conventionalize everywhere Note: a small gap to denote that this edge is filleted! Difference between true and conventional is far too great 21
Conventional Practices: Treatment of Unimportant Intersections 22
Conventional Practices: Treatment of Unimportant Intersections Preferred Treatment 23