I am not sure what to look for.  I am pocket cutting and the rectangle is coming out approximately 1/64 of an inc undersize.  This happens even when I cut a round pocket or hole.  I have not noticed a problem until I went to fit a clock insert into a hole that was too small.  All the other carving seems to be correct but I am not sure I would notice a small error is it were consistant.  But when you put 1" peg into a 1" hole that is quite noticeable.  actually I made the opening 1/32 larger than the insert for a bit of clearance and it was still tight ....  Any ideas what I should check?

Have you done a test with the circle pocket wizard to make sure its not the code that is wrong?
Is the cutter definitely the correct size that the code is thinking it is?
Hood

Yes, I checked the tool first it's within 1/2 thou so really close.  The code is generated by Vcarve.  I get a full circle or rectangle just a bit undersize.  It's strange if I were loosing stps I would think the circle would become a elipse etc.  I checked to make sure the feed screwes were tight also. 

Where is thge circle picket wizard?

Found the wizard I will have to tryt that and see if the results are the same

I just had a thought not sure if this is possible, could my 1/4 bit cutting up to 1" deep be flexing?

It will flex if cutting hard material but not likely by anything near that much,what kind of spindle is it?

Hood

it is a router motor mounted to a plate guided by V slides and bearings V that ride on the track.  Same for the X axis.  I am only cutting wood and usually only 1/8 per pass conservative on the material removal to allow the cutter to clear the flutes.  I also only run around 50 IPS not fast.

Router bearings will not be precision but even at that they should still be no where as much out as you are seeing. See what the wizard gives you and we can take it from there.
Hood

I am planning on that tonight.  It might even be the vertical and horizontal tracks with the v rollers sloppy enough for a small movement.  4" above the work surface it would not take much of a movement to move 7 thou and drag behind the gantry.....I will be looking at that tonight too.  First make the cut with the wizard see what I get then move from there.

Hi Norm,

Also might be worth checking the backlash on your axes. Have you done this?

Daniel