We received a print from a customer (attached, Non- Accumulating Customer supplied Print) with the note " Tolerance Non- Accumulating"
Also attached are drawing 1 & Drawing 2.
Does the customer want how it is dimensioned in Drawing 1, Drawing 2 or something else? If your answer is something else, please attach an example.
I can't speak to what your customer wants, but your option 2, with the Ordinate dimensions, is in my opinion the best way to achieve what he or she seems to be asking for, and the method I would use (and often do use).
in option 2, ordinate IS NOT accumulating. if the tolerance block was filled to like .005 from zero
if it was done in the picture below each hole could accumulate .005 tolerance.
if the holes were for mounting something to it, like a vendor supplied oil filter mount, I would go with below for less than 3 holes. more than three I think I would do ordinate.
That seems like a lazy way to dimension a print since it leaves ambiguity. For non-accumulating dimensions I typically use ordinate dimensions, as Justin has already pointed out. It is the responsibility of the drafter to indicate design intent with the dimension scheme used. Have them verify the scheme once you put it all together.
I wrote about this many years ago: How to dimension feature patterns on drawings ~ SolidWorks Legion
Ive heard it argued both ways and now I find myself confused. Did I get my above post incorrect? My picture seems similar to GD&T
Customer supplied print is completely incorrect. This is a mythical specification. As described in my article (linked above), ordinate and baseline dimensions are better, but they still accumulate some tolerance when measuring from hole to hole within the pattern since all dimensions are taken from the baseline. Anyway, I went through all the options in the article. GD&T is the best solution.
I'm sure the answer Matthew posted is correct, but the people using my drawings have never heard of GD&T, and since all ages have access to this forum I won't describe the reaction I'd get if I started using it.
Ha ha I completely understand. I constantly hear "just add a +- tolerance of 1/4" " or my personal favorite, this one guy refers to anything metal as "flat bar"
Yup, there is what I've called "irrational fear" of GD&T in Engineering. However, vendors (besides mom-and-pop shops) are typically don't have an issue with GD&T (and the ones that do are weeded out via competitive quote requests). It's really just the Engineers themselves with misconceptions about GD&T, and that's usually because they didn't get significant exposure to it on the job or during their education. GD&T is the preferred method as stated in the ASME Y14.5 standard.
Matthew Lorono wrote:
Yup, there is what I've called "irrational fear" of GD&T in Engineering. However, vendors (besides mom-and-pop shops) are typically don't have an issue with GD&T (and the ones that do are weeded out via competitive quote requests). It's really just the Engineers themselves with misconceptions about GD&T, and that's usually because they didn't get significant exposure to it on the job or during their education. GD&T is the preferred method as stated in the ASME Y14.5 standard.
I was specifically thinking about the construction crews who use my drawings. Their reactions to GD&T would be unprintable, after they handed the drawings back to me.
" I was specifically thinking about the construction crews who use my drawings. Their reactions to GD&T would be unprintable, after they handed the drawings back to me."
Just tell the construction crew that GD&T is the preferred method as stated in the ASME Y14.5 standard.
William Bukovec wrote:
Just tell the construction crew that GD&T is the preferred method as stated in the ASME Y14.5 standard.
It wouldn't do any good. ASME Y14.5 doesn't mean anything more to them than GD&T.
Its literally a foreign language to them and the fabricators I work with. I dont know bout Glen, But I have to hide all the crayons, sharpies, and glue when my guys come in the office else they might eat them.
Justin Pires wrote:
Its literally a foreign language to them and the fabricators I work with. I dont know bout Glen, But I have to hide all the crayons, sharpies, and glue when my guys come in the office else they might eat them.
I wouldn't go that far. They're pretty sharp, but all that is just outside their experience (and I'd never heard of GD&T when I was doing construction either).
Glenn Schroeder wrote:
Justin Pires wrote:
Its literally a foreign language to them and the fabricators I work with. I dont know bout Glen, But I have to hide all the crayons, sharpies, and glue when my guys come in the office else they might eat them.
I wouldn't go that far. They're pretty sharp, but all that is just outside their experience (and I'd never heard of GD&T when I was doing construction either).
I wish I could say the same. I started leaving out the small boxes of crayons as a decoy so they might not huff my sharpies. Office management came and took my Canned Air cus one of the guys was taking them....
Then you may wish to stick with ordinate dimensions.
Yes, always work with the weakest link.
I can't speak to what your customer wants, but your option 2, with the Ordinate dimensions, is in my opinion the best way to achieve what he or she seems to be asking for, and the method I would use (and often do use).