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Example: let's say that I have a rectangular part that I would like machined. I'd like to cut it to change the length, but the width and thickness are fine as is. The width and thickness are not nice round numbers. Is there any convention on how to communicate this through a technical drawing? Something like "AS IS"?

Related to Do I need to mention every dimension on a to-scale drawing?

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  • $\begingroup$ A drawing only needs sufficient dimensioning so every necessary point is locatable, no more than that. We were marked down by our instructors for excessive dimensions. $\endgroup$
    – Solar Mike
    Nov 24 '18 at 22:36
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There are standard symbols to show which surfaces should be machined, and which should not.

See Fig 11.3 in http://www.engr.mun.ca/~dfriis/cadkey/program/textappi.html (or preferably, read a proper standards document!)

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  • $\begingroup$ Thanks for your input, alephzero, but the page you linked to appears to be related to surface finishing only. $\endgroup$
    – drpm
    Nov 27 '18 at 14:45
  • $\begingroup$ @drpm well yes, kindof, but not material removed surface mark actually means exactly what you ask. Keep the surface of the original blank, no machining keep as is. $\endgroup$
    – joojaa
    Nov 28 '18 at 6:26
  • $\begingroup$ Also sufrace finish is how you see what was machined or not. $\endgroup$
    – joojaa
    Nov 28 '18 at 6:39
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The way to indicate dimensions that do not have to be machined is with a so-called reference dimension. The dimension used to be followed by 'REF', but nowadays the dimension is simply placed in between parentheses, e.g. (1 mm).

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  • $\begingroup$ This is actually wrong, ref does not assume its kept that way, just that its not a acceptance criteria. It in it self does not imply not machined. While you can indicate with ref that dimension is not used as acceptance you need to document the not machined elsewhere somehow, or you risk getting drawing bounced because its not complete and or somebody machining anyway. $\endgroup$
    – joojaa
    Nov 28 '18 at 6:28

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