I have a question guys. When the drawing callout is to 3 decimal places example 1.000 +/-.005, for part acceptance should be rounded off to 3 decimal as well or not? if the actual is .9946, can it be reported as .995?
I am looking for something in the standard y14.5 -94/2009 , PWA360 or really any other where it would explain how dimension should be reported and to how many decimals.
I've been reading some older threads, and came across a statement that explains per y14.5-2009 that all linear dim. are absolute regardless of number of decimal used as if they did continued with zeroes. So, if my interpretation of this statement is correct, then for the dim 1.000 +/.005 with a 10:1 resolution rule (of the tolerance), I would have to measure the feature to 3 decimal, and with an actual being .995 not .9946 ?
However if I have a dim 1.000 +/-.002, using the same 10:1 rule, I would then have to measure the feature to .0002 resolution, and with actual being .9946, it would make it OOT correct? and I cannot report it as .995 right?
Taking into account the uncertainty, you have to choose if you're the seller or the buyer..
It's the difference between rejecting a good part and accepting a bad one.
In your case, the main value is OOT, but with the uncertainty, maybe it's not... or maybe it's more OOT.
If the uncertainty is around ±0.002, the real value of the dim is between .9966 and .9926 !!!!!!
If you declare that this part is good with this uncertainty, you will be wrong at 60%!!!!!
I see your point. When you referring to uncertainty, do you mean the gage total accuracy ( like they specify on the back of the calipers +\-.002? And MPE for a CMM?).
The way I see it, the only way around this is to have a guard band of the tolerance, in this case a dim +\-.005 would be gaurd banded to +/-.003. Does this logic make sense?
I see your point. When you referring to uncertainty, do you mean the gage total accuracy ( like they specify on the back of the calipers +\-.002? And MPE for a CMM?).
The way I see it, the only way around this is to have a guard band of the tolerance, in this case a dim +\-.005 would be gaurd banded to +/-.003. Does this logic make sense?