Repeated Basic dimensions 2

[ringman]

If a basic dimension is repeated in separate views of a drawing, does this pose a problem for interpretation in any way or violate the standard? The dimension of course applying to the same feature in both views.

The drawing of course being prepared 'In compliance with ASME Y14.5M-1994.'

I looked could find no conclusive statements.

Thanks

 

[KENAT]

Paranthesis round a basic, yeah that doesn,t even sound good let alone look it. If it's a reference dim what does it matter that it's reference of a basic dimm or a +-.

ewh, that's pretty much my thinking. I just couldn't be bothered to type a bunch out given how that other thread went.

KENAT, probably the least qualified checker you'll ever meet...

 

[ewh]

Had me worried, too. This seems to be a much calmer thread though, so far...

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[ctopher]

I'll think of something...I can't have you guys being too calm.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 02, 2008)

 

[vc66]

I would keep the box off of the "reference" dimension, and just add parentheses around it. It's debatable, but I feel like a reference basic dimension is somewhat of an oxymoron.

V

 

[ewh]

If we are going into personal preferences, I have to agree with leaving the box off. It does seem like a kinda ugly kluge having a basic dimension being reference.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[btrueblood]

Ergh, dunno, ewh. If you are referencing a basic dimension, leave it basic, otherwise somebody is gonna get confused-er? My approach is to always try and annotate my kludges, like I said.

...

When the ASME committee gets around to this one, I hope they tell us whether the () go inside or outside the box. Or maybe we'll have a box with bulging ends?

...

Now, if you reference a basic dimension, and there are now two basic dimensions for the same feature on the same drawing, should you state "2X" on the original basic dimension, to indicate that you've referenced it, and how many times you did so?

 

[ewh]

That's sadistic, btrueblood

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[ctopher]

2X has nothing to do how many times the dimension is referenced on a dwg. But, most people these days building the assembly wouldn't notice the difference anyway.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 02, 2008)

 

[drawoh]

btrueblood,

A box around a dimension is part of the tolerance specification as per ASME Y14.5M-1994. If the dimension is for reference, probably, it should not show any tolerances, therefore there should be no box.

A revision could involve removing the box. Don't force a drafter to search the drawing for reference dimensions with basic dimension boxes.

JHG

 

[ringman]

I am not convinced at this time that repeating Basic dimensions on a PRO-E generated drawing would result in any sort of problem, nor strictly violate Y14.5M.

However at this time the problem is, at least temporarily, resolved. I would like to thank all who have contributed opinions.

I was rather hoping that a GURU, past or present committee person, might respond, but so it goes.

Thanks again
Ringman

 

[ewh]

Unfortunately, if it is not spelled out in a standard somewhere, questions like these boil down to opinion. Even the gurus can have differing opinions.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[MintJulep]

While I've never seen it used, making a basic dimension ref. by placing parens around it in an auxiliary view seems perfectly sensible to me.

However, having said that, I don't see the need to make any dimension in an auxiliary view a reference just because the same dimension is shown elsewhere.

It is not double-dimensioning because it does not introduce ambiguity. It is the same information, presumably the aux view is needed to clearly show something that may be too cluttered etc. on the main view.

It does not violate "Each necessary dimension of an end product shall be shown. No more dimensions than those necessary for complete definition shall be given." You are not providing more dimensions than necessary, you are making it easier to view the some of the necessary ones.

As noted above, it may cause problems if it is changed in one place, and not the other, but if everything is fully parametric/associated that can't (shouldn't) happen.

So while it may be a drawing/configuration control problem, I don't see it as a violation of drafting standards.

 

[ewh]

Depends again on interpretation. Using that logic, you can have two or more of the same dimension on a drawing, regardless of tolerancing method. After all, they're the "same dimension".
Two of the same dimension is one more than required to completely define the part.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[ringman]

Yes BUT,.... the tolerance is not associative is it? I am not a Pro E expert.

The tolerancing could result in a problem with double dimensioning.

 

[ewh]

Neither am I. I meant that it makes no difference if it is a basic dimension or a +/- dimension that is duplicated. The tolerancing would remain the same, just repeated. This is beside the point I was trying to make, which is that any duplicate dimensions are not required to define the part, and therefore should be reference.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[MintJulep]

ewh,

I think we are debating a subtle point of semantics - which is something I love to do...

In my view "double dimensioning" is the locating of a feature from two independent data. This introduces ambiguity, and must not be done.

"Duplicate" or "repeated" dimensioning is showing the exact same thing in two or more places. There is no ambiguity introduced.

If a feature is shown on both a main an auxiliary view nobody gets excited about "OMG, that feature is shown twice, whatever shall I do?" Rather it's "Oh, that was nice of the drafter, he has given me this auxiliary view at an expanded scale so that I can see what is going on here without a microscope".

Why should dimensions be any different?

 

[ewh]

MintJulep,
We are in total agreement regarding double dimensioning. As for repeating, I think that it would be even more helpful if the repeated dimension were reference, thus the reader would know that the feature is located elsewhere, and this is just a "reminder".
As for semantics... it can get very frustrating sometimes, but I think it is good mental exercise, and I tend to learn from such debates.

Believe it if you need it or leave it if you dare. - [small]Robert Hunter[/small]

 

[drawoh]

ringman,

I do not know about ProE either. In SolidWorks, the tolerances can be associative, depending on how you constructed the model and applied the dimension. Whether it stays that way or not depends on who revises the drawing, and whether or not they checked the model out as well.

How much confidence do you have in all your co-workers?

JHG