Do away with manual alignments - use Readpoint

the only problem I am having so far, is once I place the probe in the center of my diameter,(or as best placed as the eye can put it), I make that my read point. But when I go to place the actual alignment on the datum targets, they are not showing where they should.

any suggestions??

3mm sounds like it may be tip radius compensation.

Whenever possible I try to use Auto Circles to seed a readpoint. I create the hole first then insert a ReadPoint just before it. Copy/paste the hole values to the readpoint, datum to it then offset by the coordinate values if needed. The below is for the demo block hole pattern (4x). A prior document comment outlines the approximate orientation of the demo block in the Cmm volume to help with a DCC move from the 1st readpoint to the 2nd. First hole has a sample point to initially establish Z origin which happens to be the surface the holes lie in (no translation needed). Both holes have AutoMove values. Sometimes I'll do a quick DCC 3-2-1 alignment after the readpoint alignment prior to measuring the datum features. It just depends on how repeatable I want the datum features to be. I always used to take 4 hits in the holes. A limitation with setting MANRETRACT on our FDC controller prompted me to try using the readpoint. Now that I've been using it I can't see a reason to go back to the old way. I've also used it on some small machined features that are eyeballed by the machinist to the casting per customer's instructions. A limited production that didn't warrant the time to do a DCC exploration of the area. I've found it to be a quick way to corner the part so that automated measurement can begin sooner.

COMMENT/OPER,NO,FULL SCREEN=NO,AUTO-CONTINUE=NO,
            
            Position stylus at top center of front left hole (level with surface)
            
PNT1       =FEAT/POINT,CARTESIAN
            THEO/<3.6811,0.7677,0>,<0,0,1>
            ACTL/<26.6234,19.2428,-78.9025>,<0,0,1>
            READPOINT/
ALIGN1       =ALIGNMENT/START,RECALL:USE_PART_SETUP,LIST=YES
                ALIGNMENT/TRANS,XAXIS,PNT1
                ALIGNMENT/TRANS,YAXIS,PNT1
                ALIGNMENT/TRANS,ZAXIS,PNT1
                ALIGNMENT/TRANS_OFFSET,XAXIS,-3.6811
                ALIGNMENT/TRANS_OFFSET,YAXIS,-0.7677
              ALIGNMENT/END
              MODE/DCC
CIR1         =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
              THEO/<3.6811,0.7677,0>,<0,0,1>,0.5906
              ACTL/<3.6745,0.7667,0.0301>,<0,0,1>,0.5955
              TARG/<3.6811,0.7677,0>,<0,0,1>
              START ANG=0,END ANG=360
              ANGLE VEC=<0.7071068,-0.7071068,0>
              DIRECTION=CCW
              USE_PIN=NO
              REPORT VEC=<0.6532815,0.2705981,0.7071068>
              SHOW FEATURE PARAMETERS=NO
              SHOW CONTACT PARAMETERS=NO
              MOVE/POINT,NORMAL,<6.0827,0.7677,0.5000>
              MODE/MANUAL
              COMMENT/OPER,NO,FULL SCREEN=NO,AUTO-CONTINUE=NO,
              
              Position stylus at top center of front right hole (level with surface)
              
PNT2         =FEAT/POINT,CARTESIAN
              THEO/<6.0827,0.7677,0>,<0,0,1>
              ACTL/<6.0827,0.7581,0.0513>,<0,0,1>
              READPOINT/
ALIGN2         =ALIGNMENT/START,RECALL:ALIGN1,LIST=YES
                  ALIGNMENT/TRANS,XAXIS,PNT2
                  ALIGNMENT/TRANS,YAXIS,PNT2
                  ALIGNMENT/TRANS_OFFSET,XAXIS,-6.0827
                  ALIGNMENT/TRANS_OFFSET,YAXIS,-0.7677
                ALIGNMENT/END
                MODE/DCC
CIR2           =FEAT/CONTACT/CIRCLE/DEFAULT,CARTESIAN,IN,LEAST_SQR
                THEO/<6.0827,0.7677,0>,<0,0,1>,0.5906
                ACTL/<6.0705,0.7569,0>,<0,0,1>,0.5953
                TARG/<6.0827,0.7677,0>,<0,0,1>
                START ANG=0,END ANG=360
                ANGLE VEC=<1,0,0>
                DIRECTION=CCW
                USE_PIN=NO
                REPORT VEC=<0.6532815,0.2705981,0.7071068>
                SHOW FEATURE PARAMETERS=NO
                SHOW CONTACT PARAMETERS=NO
ALIGN3         =ALIGNMENT/START,RECALL:ALIGN2,LIST=YES
                  ALIGNMENT/BF2D,ZPLUS,LEAST_SQR,CREATE WEIGHTS=NO,ROTANDTRANS,USE SCALING=NO,0,0,0,359.9784
                  ITERATEANDREPIERCECAD=NO
                  Deviation Threshold=0.0003937
                  SHOWALLINPUTS=NO,SHOWALLPARAMS=NO
                ALIGNMENT/END

Lots of ways to go about it depending on what you have to work with.

They are still off after a quick 321 alignment or are you trying to avoid the 321 alignment?

No it's before the 321 alignment. When I click on the model to place the first datum, X1, it's coordinates are not where they should be.

I guess without seeing what your doing and how far it is off I'm thinking it may be due to the inaccuracy of eyeballing the probe into position. My thought was that a quick DCC 321 right after the read point should properly refine the part location accurately and eliminate any readpoint location error.

So with this, did you put it in DCC Mode right away, insert an auto circle (CIR1), then put in the readpoint PNT1 above the circle, to the location of that circle?? Then PNT2 and CIR2, but what is the ALIGN3 at the end, is that an iterative alignment??

Gomo does this technique also work with a model??