¡¾×ªÌû¡¿dimensioning to hidden lines
 

dimensioning to hidden lines
the question of whether to dimension to hidden lines came up a few weeks back and i think the reference given was slightly wrong.
asme y14.5m-1994 paragraph 1.4g (not 1.4c)
[quote] ... dimensions should be shown in true profile views and refer to visible outlines. [\quote]
my checker and i were looking for it this morning.
find a job or post a job opening
the question of whether to dimension to hidden lines came up a few weeks back and i think the reference given was slightly wrong.
asme y14.5m-1994 paragraph 1.4g (not 1.4c)
quote:
... dimensions should be shown in true profile views and refer to visible outlines.
my checker and i were looking for it this morning.
(sorry user error)
asme y14.5 para 1.4(g)
if the original post refered to para 1.4(c), then you are correct, it was a typo.
ewh, it wasn't a dig. your original post pointed us in the right direction, just thought i'd post the paragraph in case anyone was looking.
my checker just got a drawing from another division of the company to look at which leaves a little to be desired, this is just one of the issues. being from another division he was being extra cautious and making sure he could back up any changes from the standard.
no problem! this is a prime example of why we should use this forum as a resource, but not as a final authority.
a pretty fundamental rule: don't dimension to hidden lines.
tunalover
kenat,
the standard says "should" as opposed to "shall". sometimes, i hate adding a section view to an otherwise, simple, easily read drawing.
okay, i am being pedantic.
jhg
hey, i'm just quoting the standard, i'm making no judgment.
ok that’s a lie i do have an opinion but it’s my opinion not a rule, unless one day they’re dumb enough to make me a checker…�br />
you bring up an interesting point on the should/shall. my checker occasionally moans that when the standard changed from mil spec to the asme that it got watered down and a lot of the shalls got replaced by shoulds. i wonder if this is a case in point.
i frequently add sections for just one or two dimensions. to me it’s usually clearer, and using 3d cad to generate the drawings hardly takes longer, than dimensioning to a hidden line. however, i’m sure it confuses some of the people who don’t really know how to read a drawing.
i like creating a broken-out section in the view you are trying to dimension a hidden line. this creates a non-hidden line in that view, without having to create another view just to show a dimension to 1 would be hidden line.
pdybeck,
a broken out section is easy to do on a drafting board, and hard to do in 3d cad like solidworks.
my understanding is that "should" and "shall" are used deliberately in standards, with a precise grammatical meaning.
dimensions to hidden views are bad practise, and should be avoided. sometimes, avoiding them is a lot of work, and it does not accomplish much. your primary objective is to provide clear, unambiguous information, and on simple stuff, a dimension to a single, clear hidden line is clear and unambiguous.
jhg