Fit To Datums

But I still want it to show it the way it USED TO, show the MMC of the datum as a bonus to the MMC of the feature. I want the datums as datums, not floating-datums, and the location of the hole to be shown as a deviation FROM THE DATUMS, not the 'best fit on a pin' location and how much the datums were shifted.

What happens when the datum hole is MMC as well as the dimensioned hole, but the assembly method uses a tapered pin that goes in the datum? The datum hole WILL BE ZERO, not shifted, and I need to know, WITH A SINGLE DIMENSION, how far out of relationship the dimensioned hole is. THIS is how Pcdmis used to do it, and if this is the type of dimension you need, then you HAVE to do an alignment BEFORE dimensioning the hole and god help you if you need to MMC bonus from the datum hole for the dimensioned hole, you can't get it any more, unless you do a bunch of assignments and add it to the MMC tolerance, then try to explain THAT to the customer.

OK, 'they' (that same infamouse 'they' that always comes up) say the current way is the correct way (but 'they' said the same thing BEFORE they changed it, too!), BUT only if the datum hole is to be put on a straight pin, not a tapered pin. If a tapered pin is used, then the old way is the way it needs to be. BOTH case are correct use, but ONLY 1 is offered to us at a time (I think you have to go back to V3.2063 to get the other method). Why not offer us BOTH? Then they would not have had to ADD the 'datum shift' dimension. Hey, some people do not allow the datum shift (no matter WHAT the GD&T says, but they will allow the MMC from the datum), so I am still bent over a barrel if I need to MMC from the datum hole BECAUSE they do not any longer have the 'taper pin' TP method/option of reporting TP.

But I still want it to show it the way it USED TO, show the MMC of the datum as a bonus to the MMC of the feature. I want the datums as datums, not floating-datums, and the location of the hole to be shown as a deviation FROM THE DATUMS, not the 'best fit on a pin' location and how much the datums were shifted.

What happens when the datum hole is MMC as well as the dimensioned hole, but the assembly method uses a tapered pin that goes in the datum? The datum hole WILL BE ZERO, not shifted, and I need to know, WITH A SINGLE DIMENSION, how far out of relationship the dimensioned hole is. THIS is how Pcdmis used to do it, and if this is the type of dimension you need, then you HAVE to do an alignment BEFORE dimensioning the hole and god help you if you need to MMC bonus from the datum hole for the dimensioned hole, you can't get it any more, unless you do a bunch of assignments and add it to the MMC tolerance, then try to explain THAT to the customer.

OK, 'they' (that same infamouse 'they' that always comes up) say the current way is the correct way (but 'they' said the same thing BEFORE they changed it, too!), BUT only if the datum hole is to be put on a straight pin, not a tapered pin. If a tapered pin is used, then the old way is the way it needs to be. BOTH case are correct use, but ONLY 1 is offered to us at a time (I think you have to go back to V3.2063 to get the other method). Why not offer us BOTH? Then they would not have had to ADD the 'datum shift' dimension. Hey, some people do not allow the datum shift (no matter WHAT the GD&T says, but they will allow the MMC from the datum), so I am still bent over a barrel if I need to MMC from the datum hole BECAUSE they do not any longer have the 'taper pin' TP method/option of reporting TP.