So the issue is we have a part that is a cylinder with a non flat surface for the main datum. When you set it on the surface plate it will rock. The engineers say that does not matter as the measurement allows for the rocking to fall within the measurement envelope. I say it falls out of tolerance due to it not being flat so the perp of the axis is no longer perfectly perp from the datum. I have done this on the height gauge and found the center axis is not perp due to the datum not being flat. i am calling the part out. I am told i am wrong. thought feelings etc.
Correction the face that is not flat is datum B datum A is a center line.
B is Flat and there is a milled angle / draft / chamfer on 1 side of it ? I would treat it as such. If indeed it is not flat ( as in you are treating the whole surface , angle and all as B ) " where " will you measurement come from ? An average of points all over this surface will " average " depending on how many you take on the flat vs. angle. Sorry, but thats a s%!t show. Treat B as flat surface and ignore the " rest ". You need to explain to to " whomever" what they are asking for doesnt make sense. The " off angle / chamfer " related to B really has to have a " form control ". It cant just " exist " with no control. If this is the case, make it flat and you still have a good part.
B is Flat and there is a milled angle / draft / chamfer on 1 side of it ? I would treat it as such. If indeed it is not flat ( as in you are treating the whole surface , angle and all as B ) " where " will you measurement come from ? An average of points all over this surface will " average " depending on how many you take on the flat vs. angle. Sorry, but thats a s%!t show. Treat B as flat surface and ignore the " rest ". You need to explain to to " whomever" what they are asking for doesnt make sense. The " off angle / chamfer " related to B really has to have a " form control ". It cant just " exist " with no control. If this is the case, make it flat and you still have a good part.
The idea of make it flat and it is good is exactly what they are asking me to do.
talking function now not measurement.
The issue is when you butt this part up to the matting surface(datum B) it does not sit flat that is causing the part down the Datum A axis to be off. What I am telling them is that if Datum B was flat and held with some sort of control then datum A would run true and the whole assembly would function as needed.
