runout

[WolfMan]

I have a callout on an ID runout .002 -B-. Datum B is another OD.

So, the roundness of the ID is .0000. The actual location is X.0 Y .002. Wouldn't that mean that the runout is very close to .002 ??

CMM report shows runout .005

[kingsld1]

I have a callout on an ID runout .002 -B-. Datum B is another OD.

So, the roundness of the ID is .0000. The actual location is X.0 Y .002. Wouldn't that mean that the runout is very close to .002 ??

CMM report shows runout .005

Under these conditions, I could see .005. If you put Datum B in a V block and rotated the part, the features center would rise and fall .004. Assuming that some rounding is going on .005 is entirely possible.

[NinjaBadger]

Under these conditions, I could see .005. If you put Datum B in a V block and rotated the part, the features centre would rise and fall .004. Assuming that some rounding is going on .005 is entirely possible.

+1 diametrical tol zone init blud!

Not to mention location will just be giving the deviation of the features defined xyz point, the other end of the cylinder could be worse.

[dph51]

Those pesky vectors!
http://youtu.be/fVq4_HhBK8Y

[mdobb829]

Is this a round part or some type of housing? If it's a round part you can verify the runout in vee blocks or between centers with an indicator. I always hate when engineers assign runout to diameters in housings. Runout, as per the ASME 14.5 standard, must be ROTATED about the Datum axis. That's pretty hard to do with a Housing. In reality the CMM is reporting Position. You show your .002 dimension in three place decimal. If I were to guess, opening up the decimals to four place may show the location something like .00023" or .00024". In three place decimal, the CMM would round these numbers down to .002. The calculated Position in four place decimal would be .0046" or .0048". The CMM would round them both up to .005"

[WolfMan]

Under these conditions, I could see .005. If you put Datum B in a V block and rotated the part, the features center would rise and fall .004. Assuming that some rounding is going on .005 is entirely possible.

Ahhh yes yes, and fall, sorry i didnt think about the fall part. The part is large so I couldn't set it up in the V.

[WolfMan]

Its a housing looking part.

Is this a round part or some type of housing? If it's a round part you can verify the runout in vee blocks or between centers with an indicator. I always hate when engineers assign runout to diameters in housings. Runout, as per the ASME 14.5 standard, must be ROTATED about the Datum axis. That's pretty hard to do with a Housing. In reality the CMM is reporting Position. You show your .002 dimension in three place decimal. If I were to guess, opening up the decimals to four place may show the location something like .00023" or .00024". In three place decimal, the CMM would round these numbers down to .002. The calculated Position in four place decimal would be .0046" or .0048". The CMM would round them both up to .005"

[WolfMan]

Yes, after reading some replies I realized that i did not think aboit the rise and FALL, which is also taken into the account. I i got it now, thank you all.

Its a housing looking part.