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Multiple Reference Dimensions


New member
Hello All,

We are in the process of trying to create design and drafting standards where I work, and where possible, we are trying to follow the standards already set in place by ANSI.

We occasionally have to supply prints to vendors who request certain reference dimensions to be called out. Sometimes we have the same reference dimension applied in several locations, but now that we're setting up standards, we want to be sure we're using the correct format. We've looked thru all of the ANSI and ASME references that we have, but we can't find anything really specifying the format of calling out multiple reference dimensions on a drawing. For instance, we currently use the format (2X R4.5) for a radial dimension of 4.5 used in two places. But we have seen other drawings that use 2X (R4.5).

Which format is correct? Can anyone direct me to a source where this is spelled out exactly? I know this may seem like a minor matter, but we've had some big problems in the past over mis-communication from even smaller details.

Any help would be greatly appreciated.

Best Regards,



New member
ANSI Y14.5m 1.7.6

The method for identifying a reference dimension (or reference data) on drawings is to enclose the dimension (or data) within parentheses.

ANSI does not cover your situation at all. Normally the dimension would be shown as (R4.5) leaving out the 2X. The reason is, you are just attempting to show the dimension covered elsewhere from another perspective. I would leave it at (R4.5) because if you change the print, now you have two areas of change instead of just the one, which could lead to a possible drawing error and you certainly don't want a drawing error due to a reference dimension.


New member
Following up on what Don has stated, ref to ANSI Y14.5M 1.9.5 to see general repetitive features or dimensions. You would not need to use a repetitive number with a reference dimension.

Steve C


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