I built a dual table 5 axis router with parallel Y axis tables.  Since I use B and C for my 2 axis rotary head, the axis parallel to the Y table I call U (which I believe is the linear of A in Mach4) since it is the only one available - I believe the correct convention for parallel to Y is V, but that is linear of B axis and I am using B.

Problem I am running into is when I try to cut a 3A circle using I and J on the parallel table (say G3 X1.0 U1.0 I.25 J.25 F100. I get X & Y movement not X & U).  When I do this, even though the code shows U, the Y table moves instead of the U table.  I am guessing since I am using U as the second Y axis, the I J doesn't work since J is Y offset to center of arc.  How would I code a circle cut on my parallel table???