Equal distance dimensions 1

[jgabrasives]

Hello,
I have usually made drawings where a pattern if holes appears, and I usually when I use linear dimensions I dimension everything, but I haven't seen many examples that show how to say that the set of holes repeats a # of times for a specific distance. Except for the file attached, I didn't even know that the "=" could be used?
Anybody has other examples of multiple equidistant dimensions?

thanks for the help.

 

[CheckerHater]

I've never seen "equal" sign used like that.
The common way looks like this (taken from ISO standard, ASME has similar clause):

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[mkcski]

I would not recommend this symbology. Because nothing can be perfectly equally (spaced), what it the tolerance on equally (spaced)? I recommend direct dimensions with tolerances for clarity and add "3X' to show repetition. Of course this will allow tolerance accumulation unless you use "ladder" dimensioning.

 

[KENAT]

Well mkcski, it's in the standards but you make a valid point. If used on hole patterns with basic dimension though, no problem.

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[KENAT]

Just realized, as well as not being a notation style I'm familiar with the OP's example seems to be missing a dimension (one infers that the top gap is also .035 at risk).

Posting guidelines faq731-376

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(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​

 

[pylfrm]

In OP's example, the dimensions indicated by "=" would be nonterminating decimals (.066...). That may be part or all of the reason for the method shown. One way around this problem allowed by ASME Y14.5-2009 is to just write the dimension as a fraction (.200/3). See para. 1.3.22 and Fig. 7-30. Another option might be "EQLSP" after the feature callout. This is shown in Fig. 4-38, but I don't see it described in the text.

Direct tolerancing is supposed to be reserved primarily for size dimensions, so I'd say most methods of locating features (equally spaced, repeating, or otherwise) should generally be used with basic dimensions only. The examples in the standards often don't show the boxes, but I consider this to fall under the "figures are incomplete" category. I just assume there's a hidden "UNTOLERANCED DIMENSIONS ARE BASIC" note to go along with many of the figures.

- pylfrm

 

[mkcski]

pylfrm

I totally agree with your statement that direct tolerancing is for size only. Given that, the part cries out for profile of a surface tolerancing where all dimensions are BASIC.