Linear or Ordinate Dimensions
Linear or Ordinate Dimensions
(OP)
All,
What's preferred in today’s industry? Linear or Ordinate dimensions. I prefer Linear and guessing Machinist would like to have that way as well. Am I correct in this assumption?
I know there's no right or wrong answer, I'm just trying to get a feel what machinist would prefer.
Thanks,
What's preferred in today’s industry? Linear or Ordinate dimensions. I prefer Linear and guessing Machinist would like to have that way as well. Am I correct in this assumption?
I know there's no right or wrong answer, I'm just trying to get a feel what machinist would prefer.
Thanks,
Macduff 
Colin Fitzpatrick
Sr. Mechanical Designer
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RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
I think ordinate dimensioning is fine if you have a simple part that doens't require a high degree of accuracy applied to it's tolerances. Or if you have a drawing that either doesn't have any general tolerances or says something like, "ALL LINEAR DIMENSIONS ARE ±0.5, UOS."
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
If they matter surely putting a positional tolerance or MMC solves that.
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
I make things easier to read for machinists when I can, but design comes first.
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
"I think there is a world market for maybe five computers."
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RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
Having some knowledge of the machine shop and inspection practices helps.
Chris
Sr. Mechanical Designer, CAD
SolidWorks 05 SP3.1 / PDMWorks 05
ctopher's home site (updated 06-21-05)
FAQ559-1100
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RE: Linear or Ordinate Dimensions
Tolerance stack up is irrelevant for me because all my holes are located by positional tolerances. As noted above, if you have more than two holes, you have tolerance stack up, ordinate dimensioning or no ordinate dimensioning.
Sometimes, on simpler parts, linear dimensioning is clearer, in which case I use it.
JHG
RE: Linear or Ordinate Dimensions
RE: Linear or Ordinate Dimensions
Tolerance stackup--there isn't any. Stackup is when one feature is dimensioned off another feature, thus inheriting the other feature's tolerances and any tolerances that feature inherited, or in an assembly situation where parts are adding their tolerances to the whole assembly's tolerances. If all the ordinate dimensions (cartesian) have the same tolerance then ANY two features have the same tolerance between them. True, the tolerance of each feature is added to the tolerance between them, but this isn't stackup—you'll get the same thing with baseline dimensioning but take up more space. If this is a problem, adjust the tolerance so it adds up to what you want. Or use GD&T.
RE: Linear or Ordinate Dimensions
If there is such a case, might someone be so kind as to briefly describe for the benefit of all of us.
RE: Linear or Ordinate Dimensions
Fig. 1-50 has no positional tolerance, just cartesian tolerances (± applied to the dimension). By the by, I have never used the method in Fig 1-50, I usually use Fig. 1-49 and callout holes with a leader. and usually all my ordinates are basic and my hole coding is applied to patterns, not sizes, 6X Ø.138 THRU, HOLES "A" [GD&T FRAME], 5X Ø.138 THRU, HOLES "B" [GD&T FRAME], and so on.
I see ordinate dimensioning as just another of many tools for accomplishing the task of clearly transmitting the information to manufacturing and inspection.
wgchere