Cad models to nominal or to print

So to those that draw models. Do you build them to print tolerance exactly or do you build them to nominal?
example a hole that is 1" plus .004 minus 0. Do you build the model so it's 1.002" or per the print 1" plus .004 minus 0? If you build to nominal is that affecting your pcdmis program?

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Schlag over 1 year ago

Build it at nominal !!! YOu can adjust CMM prg easy if needed. More importaint that the CNC ( or mold or whatever) is shooting for the bullseye !
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Matthew D. Hoedeman over 1 year ago in reply to Schlag

yeah, but in his example, the bullseye is 1.002, not 1.000 for machining purposes. If the machinist tries to make it at 1.000, and is a touch under, it is bad, if he shoots for 1.002 and is a touch under, it is OK. The CNC guys need something 'different' for making than the inspectors needs to checking when it is a unilateral tolerance, as you will NEVER get them to understand it.
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Matthew D. Hoedeman over 1 year ago in reply to Schlag

yeah, but in his example, the bullseye is 1.002, not 1.000 for machining purposes. If the machinist tries to make it at 1.000, and is a touch under, it is bad, if he shoots for 1.002 and is a touch under, it is OK. The CNC guys need something 'different' for making than the inspectors needs to checking when it is a unilateral tolerance, as you will NEVER get them to understand it.
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