I am confused as to why I am getting inconsistent lines when surfacing my spoil board with a 2" cutter (1" step over) after tramming to .004" difference over 6" inches. The existence of the lines is not so much the greatest concern (should it be at .004"?), but the inconsistency of the lines is what I do not understand. Why would I get lines is some areas but not consistently across the spoil board?
I trammed my Joe's Hybrid CNC using a tramming squaring from SST with two dial indicators. With the gantry near centered on the x and y axis, the front to back measurement is about .004" different and the left-to-right is about .0005" different. Both of those measurements are across 6" from dial indicator to dial indicator. The dial indicators are measuring against a 1/4"x20"x20" piece of glass that has been made parallel to the x and y axis prior to the measurements/adjustments above. Example: https://cdn.thingiverse.com/assets/8...132807_200.jpg (not my image, but that is the technique I used)