Verification of Profile of Surface tolerance
Verification of Profile of Surface tolerance
(OP)
This is probably a simple question, i believe the standard (1994) explains it but i just wanted to verify with others who are more knowledgeable than me.
The attached pdf shows a part in which a 'profile of surface' of .020 to Datums A & B is called out, with all dimensions boxed in as Basic.
My question deals with the 1.825 diameter in which actual measurement is .0106 undersized (1.8144).
According to Y14.5-1994 section 6.5 Profile Control:"...the true profile may be defined by basic radii, basic angular dimensions, basic coordinate dimensions, basic size dimensions..." i looked at figure 6-17 which calls the diameters to be within the .025.
So in the case of the attached pdf, will this tolerance be a +/-.010, thus the measurement falls out of tolerance?
In the CMM program, the profile of surface has a +/-.010 due to form and location callout, but the actual profile measures to roughly -.006, according to the CMM it appears to still pass even though its below the .010 mark.
Can someone shed some light on this for me?! Thank you for your time and help
The attached pdf shows a part in which a 'profile of surface' of .020 to Datums A & B is called out, with all dimensions boxed in as Basic.
My question deals with the 1.825 diameter in which actual measurement is .0106 undersized (1.8144).
According to Y14.5-1994 section 6.5 Profile Control:"...the true profile may be defined by basic radii, basic angular dimensions, basic coordinate dimensions, basic size dimensions..." i looked at figure 6-17 which calls the diameters to be within the .025.
So in the case of the attached pdf, will this tolerance be a +/-.010, thus the measurement falls out of tolerance?
In the CMM program, the profile of surface has a +/-.010 due to form and location callout, but the actual profile measures to roughly -.006, according to the CMM it appears to still pass even though its below the .010 mark.
Can someone shed some light on this for me?! Thank you for your time and help





RE: Verification of Profile of Surface tolerance
RE: Verification of Profile of Surface tolerance
In this case, all the dimensions, diameters and angles are all boxed in (Basic) but there is no mention of tolerances or anything of the sort except for the profile of a surface callout to .020 of Datum A & B with the "all around" symbol pointing to this callout.
i believe a surface of profile in this case is bilateral thus needing to be within the .020 all around the part. i'm uncertain however if this means that the tolerance for this diameter is 1.825 +/-.010 but profile says it is good.
So is this diameter acceptable?
RE: Verification of Profile of Surface tolerance
1.8144 itself can't provide you information that you are inside or outside of the tolerance zone for profile callout because by nature it is not checking location of actual profile of a part.
RE: Verification of Profile of Surface tolerance
RE: Verification of Profile of Surface tolerance
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Verification of Profile of Surface tolerance
RE: Verification of Profile of Surface tolerance
RE: Verification of Profile of Surface tolerance
A surface profile is a boundary control; as long as the feature is within that boundary, that's all you care about. In this case, your boundary is centered on the datum-B axis. So, you set up the workpiece using datum simulators for datum-A and datum-B, then master your indicator at .9125" from the axis of the simulator. As you rotate the part about the datum axis simulator and move the indicator over the cylindrical surface, as long as your indicator doesn't move more than +/- .01" then you're ok. The CMM just does this all behind the scenes which makes it more confusing.
Jim Sykes, P.Eng, GDTP-S
Profile Services www.profileservices.ca
TecEase, Inc. www.tec-ease.com