【转帖】sharp edge tolerance

yang686526

sharp edge tolerance?
just started a new job and they don't have any asme / ansi specs here!  anyone tell me what tolerance i have on a sharp corner callout per ansi y14.5m-1982?
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the tolerance is whatever you call out on the print. the asme specs don't tell you what the tolerances are, they just tell you how to interpret them.
david
if i understand your question correctly i agree with aardvarkdw answer.
i don't have ansi y14.5m-1982, only asme y14.5m-1994 which replaced it but i dont think it says anything.
we put the following note on our drawings to address this:
remove all burrs and sharp edges ____ max radius or chamfer.
we select the value based on function of the part.
kenat, probably the least qualified checker you'll ever meet...
actually the issue is i am measuring a part with a callout of " sharp corner, do not deburr".  i always used a .002 max edge break for a default on a sharp corner and thought there might be an actual tolerance listed in a spec.
if it says
quote:
sharp corner, do not deburr
i'd think the max edge break would be less than .002.  i'm thinking knife edge, but i'm no inspection guy.
kenat, probably the least qualified checker you'll ever meet...
i would talk to the designer and ask them what they mean by "sharp". without an edge break or corner round callout you have nothing to measure.
technically "sharp corner" should mean that the point is exactly a molecule wide, anything less than that and you no longer have a theoretically perfect corner. that however, is ridiculous, so i would ask the designer what is acceptable.
david
it is very vague. if you call out a sharp corner, you will get different corners based on various machine shops. it can have a small radius or a razor sharp edge. a r.002 is common. as they others wrote, there is not a spec for a simple corner ... only threads, o-ring grooves, etc.
chris
solidworks 07 4.0/pdmworks 07
autocad 06
"do not deburr" is a process (or lack thereof), and does not belong on the engineering drawing.
the existence of such a statement on the drawing suggests that the designer had a specific manufacturing process in mind for the part as a whole.  the size and "sharpness" of an edge or burr is very much process dependent.  consider a shear, a band saw, a wire edm, an end mill or a disk grinder.  all could be used to make a similar feature, but the edge would be very different.
in order to get the 'sharp' edge i think you're really after, we add the note: no nicks or burrs allowed.
it's not so much a defining "how sharp is sharp" or another one we have come across here. "how clean is clean", it's more of a case of uniformity of the edge.
ie. profile of a line ......(even if circular ..)
the statements such as "no burrs" or "no sharp edges" shown on  drawings is fuzzy to say the least and it is difficult to get a usable or measurable definition out of engineering. it is usually sluffed off to quality to come up with some sort of standard which, i think, is wrong.
product standards should come from the design engineering group and not quality. quality would then come up with the best way of measuring the standard as long as the standard is measurable.
what do you think? am i wrong here?
dave d.
dingy, i think i agree.  hence the standard note we have specifying a max value for burrs or sharp edges.  
of course we dont specify a min value but i'd hope in our notes case it was fairly clear.
if i wanted a sharp edge i'd probably reword our note and put a very low maximum.
kenat, probably the least qualified checker you'll ever meet...