Next phase of calibration ... making sure that parts fit! First test was the 20mm cube. I think it looks great on the bed. This is an ABS print and you can see how stuck it is on the DR-4. In fairness I have probably smushed the first layer a little more than is needed and may adjust the build platform down a smidge. One of the nice things about FR-4 is that it seems to be forgiving on the first layer being overly tight. Of course this leaves a ridge of plastic that is not always appropriate!
Anyway. The important thing about the 20mm cube is whether it has been printed as a 20mm cude. Measuring this one shows 19.90 and 19.96 with a height of 9.94. I think that I am pretty happy with those dimensions.
On to the thin wall test. First pass not looking so hot as I think that a .4mm thin wall test should measure at 0.4mm!
I have paused on this task for a while. My printer is producing output that is dimensionally stable to itself and I am happy with that for now.