tolerances

Size, shape and tolerance are all important.

It is almost impossible too manufacture components with precise measurements. The tolerance is set to specify the maximum deviation allowed before the component becomes unusable for the original purpose.

When the tolerance is exceeded the part must be considered a different size.

Thanks for you answers, I do have another.

1. When precision surfaces are required on a casting, which one of the several types of castings is most likely to need a machining operation subsequent to casting? Which two types are least likely to need subsequent machining?

That all depends on the complexity of the part and its function.

Why do you insist on others doing for you what you should be doing for yourself.

You are cheating yourself by sloughing off your HOMEWORK for others to do.

Get smart, and get to WORK on YOUR WORK.

Damnit S Stan! Have I been out of school that long? I completely missed it. But not you; you 'ol hound dog! You sniffed the bugger right out!

I would like to resend my previous reply and in it's place, substitute Stan's.

cr3

I concur S Stan's got a great nose!

Way to tell him...

Form, Fit and Fuction... All equally important.

There is your answer i a nutshell. When one aspect is deemed more important than another GD&T symbology and notes will indicate so by us of such as MMC, circularity, flatness and the likes.

I am looking right now at ASME Y14.5M-1994 in it's entirety and it is well over 1000 pages. All adressing this matter.

cr3

The straightness tolerance can be applied to either a cylindrical or flat features. For a cylindrical feature, there are two possible intentions. When applied to the cylinder's surface, the symbol's intent is to control the straightness of each individual line element making up that surface. When attached to the diameter dimension line and the diameter symbol is contained within the feature control frame, the cylinder's centerline is being controlled within a cylindrical tolerance band of a specific size. When the straightness symbol is attached to an otherwise flat surface, the line elements lying on he surface of the part and running parallel to the straightness symbol are being controlled.