huangyhg

tolerances block interpretation
our company has established certain procedure in regard to the standard tolerance block in the drawing format. recently, i notice that the interpretation of these tolerances is awkward.
our standard tolerance for 3 digits behind decimal is .xxx 卤.005. occasionally we have other dimensions that required tighten tolerance such as 卤.002. so, in order to eliminate repetitive 卤.002 on each critical dimension, we created another standard tolerance with 4 digits behind the decimal just for the 卤.002. this is how it looks now:
.xxx 卤 .005
.xxxx 卤 .0020
i think the four digits tolerance should not be mixed with three digit tolerance value. i have never seen this kind of format before. can anyone tell me if the above format violated ansi y14.5m-1995 standard? or latest.

sincerely
no, what you have there is fine since you have 4 places for the dim value and tolerance, with that last zero being significant.
if you had .xxxx ± .002
that would be wrong.
--scott
thanks scott
i've seen many us companies use different decimal place values to specific standard tolerances.
i've been told that us and euro interpret decimal place numbers differently. in european countries; 0.01 means exactly the same as 0.0100, but in us the more decimal places would indicate a tighter (or more precise) tolerance (even though it's the same numerical value). any comments?
that's an ansi/asme vs iso standard. in ansi, the trailing zeros are significant digits defining a tolerance. in iso, they are not and are therefore excluded. interestingly enough, iso standard keeps the leading zeros, though, as in 0.01 vs .01.
--scott

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