Linear Dimension to GD&T Callout
Linear Dimension to GD&T Callout
(OP)
Hi All
Used this forums many times but never posted. I've got a query regarding converting a basic linear dimension using a specification to a GD&T callout this is the example below.
If the specification states a hole location is +/-0.3 from a edge what would this equate to for the feature control frame:
POS|dia??|A|B|C
Most drawings I deal with are fully GD&T and its not very often I need to refer back to a specification but I remember there is some form of specific conversion
Thanks in advance
Used this forums many times but never posted. I've got a query regarding converting a basic linear dimension using a specification to a GD&T callout this is the example below.
If the specification states a hole location is +/-0.3 from a edge what would this equate to for the feature control frame:
POS|dia??|A|B|C
Most drawings I deal with are fully GD&T and its not very often I need to refer back to a specification but I remember there is some form of specific conversion
Thanks in advance





RE: Linear Dimension to GD&T Callout
The most typical "conversion" everyone is looking for is square root of 2 or 1.4
So it makes dia 0.85
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RE: Linear Dimension to GD&T Callout
a2 + b2 = c2 -> .32 * 2 = .18
√.18 = .42426 = r
2 * r = TP Ø = .8485
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RE: Linear Dimension to GD&T Callout
Usually in situations like this the approach is to set diameter of the cylindrical tolerance zone at 0.6*sqrt(2), but that gives a tolerance zone that is approximately 57% larger in area in comparison to square +/-0.3 tolerance zone. In most cases this is exactly how position of a hole should be defined, but that is not 1 to 1 transition from square tz.
However, if that is really what function requires (which I doubt), you can define a square tolerance zone of 0.6 width/height using a method shown in fig. 7-28 (Y14.5-2009) or fig. 5-41 (Y14.5M-1994); if you put 0.6 in both feature control frames (with no M modifier) you will define 0.6x0.6 tolerance zone.
RE: Linear Dimension to GD&T Callout
now its been mentioned i recognise using that equation to calculate before
what a great forum!