calculating CPK's

The suggestion above to edit the lower tolerance and make it negative of the TP tolerance won't have any effect on the Cpk (or Ppk) calculation.

Er, yes it will, it will force Datapage to calculate the Cpk (Ppk) to the upper limit (positive TP tolerance) because that WILL be the closest limit for it to calculate the value to since the average will ALWAYS be greater than zero. Pp/Cp is the only option for one-sided tolerance you can change in Datapage, Cpk/Ppk always uses the total tolerance band, no matter if it is a one-sided tolerance or not and in the case of TP, since the lower tolerance limit is also the absolute limit for a reading (impossible to get a negative TP value) it will calculate Cpk/Ppk to that limit IF the average is less than 1/2 of the TP tolerance. Cpk/Ppk is always calculated to the closest tolerance limit. If you TP tolerance is 1mm and your average is 0.1mm, then the Cpk/Ppk will be calcualte to the 0 limit and not to the 1.0 limit, and, unless you have almost no variation, it will fail due to it being so close to the tolerance limit of zero when in reality, it should be a much greater value, ie calculated to the 1.0mm. BUT, TP should not be used BY ITSELF for any SPC calculation. The individual axis MUST be included in order to have any idea of the actual capability of the hole location.

The suggestion above to edit the lower tolerance and make it negative of the TP tolerance won't have any effect on the Cpk (or Ppk) calculation.

Er, yes it will, it will force Datapage to calculate the Cpk (Ppk) to the upper limit (positive TP tolerance) because that WILL be the closest limit for it to calculate the value to since the average will ALWAYS be greater than zero. Pp/Cp is the only option for one-sided tolerance you can change in Datapage, Cpk/Ppk always uses the total tolerance band, no matter if it is a one-sided tolerance or not and in the case of TP, since the lower tolerance limit is also the absolute limit for a reading (impossible to get a negative TP value) it will calculate Cpk/Ppk to that limit IF the average is less than 1/2 of the TP tolerance. Cpk/Ppk is always calculated to the closest tolerance limit. If you TP tolerance is 1mm and your average is 0.1mm, then the Cpk/Ppk will be calcualte to the 0 limit and not to the 1.0 limit, and, unless you have almost no variation, it will fail due to it being so close to the tolerance limit of zero when in reality, it should be a much greater value, ie calculated to the 1.0mm. BUT, TP should not be used BY ITSELF for any SPC calculation. The individual axis MUST be included in order to have any idea of the actual capability of the hole location.