【转帖】14.5m-1982 vs 14.m-1994

yang686526

14.5m-1982 vs 14.m-1994
hey guys,
   i'm trying to get a list of about 4-5 big changes that you would see between the old ansi y14.5m 1982 and the asme y14.5m 1994.  i know it's probably dependent on the drawing but i'm just looking for the big obvious changes.
thanks,
pete
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the best place to find these would be the 1994 standard.  some significant changes are listed in the forward and the appendices.
when the people fear their government, there is tyranny; when the government fears the people, there is liberty.fff"> - thomas jefferson

yeah, look at appendix d of 14.5 it lists former practices.
kenat, probably the least qualified checker you'll ever meet...
yes, appendix d.
the changes that jump out at you are:
1. using the dumb looking iso plunger datum symbol vs the letter within dashes.
2. not using the circle s (rfs)symbol in the fcf, since rfs is the default with 1994.
3. controlled root radius (cr) is now what r used to be in 1982. (need to read section 2.15 in 1994 spec)

cr is under utilized from what i've seen.  a lot of people still don't know what it is.  i get asked about it from time to time from co-workers and shops.  then again, there's a lot of people that don't know what sr is either.  i actually get frustrated when i get asked about that.
matt lorono
cad engineer/ecn analyst
silicon valley, ca
i was thinking the same thing about cr fcsuper, i probably need to be more diligent about applying it.
as to frustration about sr, i see your annoyance and raise it 10 fold.
kenat, probably the least qualified checker you'll ever meet...
don't forget the additional fundamental rules. they are the last two on the list.
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lol (literally) kenat
also, please note that asme currently has a new version of asme y14.5m in the works right now.  it may be released this year, but don't hold your breath.  i'm guessing the standard will eventually be asme y14.5m-2009.
matt lorono
cad engineer/ecn analyst
silicon valley, ca
can't wait for the new y14.5, fcsuper, hopefully i will be retired (again) by the time it comes out.
a bit off topic to the op but since it was commnted on:
one has to be careful with the use of cr.
one of our programs added a standard drawing note that "all radii be cr unless otherwise specified."
the intention was to inspect cr's the same as the old r's were under the 1982 spec (for tangential radii only).
inspection went hog wild, however, and started inspecting all of them with magnification and cast molds, looking for flat spots, radii reversals and tangental mismatch, and writing a lot of rejections.
obviously, the note was too broad, and we since have restricted cr usage to highly stressed and fatigue critical areas which are identified by stress analysis (or analysts).
just to clarify, since it came up here recently:
the bottom of a blind ball end milled hole would be an sr
(not sr full), and an internal spherical feature >180° i.e. the reverse of fig 5-62 would be an s?.
agree??
  
and then there are the extended principles for composite tolerancing.  about 100 pages worth.