Side to side on blade is 1/16" in a 19" cut
That's 0.2º - this should easily be detected with a Digital angle finder.
but if I'm making parallel cuts would the difference on the bed or blade cause the discrepancy on the flip.
It could be either. To fix it you could adjust the bed to the blade or the blade to the bed, it doesn't matter which one you do.
It does assume the bed is parallel to itself all the way along which it may not be (see below_
I know this is really simplistic but just to see if I have a handle on it.....I wouldn't see a difference if I didn't turn the log?
Sorry I didn't make it clear in my previous post.
Once again I assume the bed is parallel to itself all the way along, and if so, you should get parallel cuts.
In the picture below, the bed is not parallel to the ground and the blade is not parallel to either.
Except for the first and last cuts, the cuts should be parallel.
However you won't get parallel or square cuts when the log is flipped. To do this the blade and the bed must be parallel all the way along the bed.
The way I do mine is I park the mill on one end of the mill rails lay a long piece of rectangular hollow Ally across the bed and set my DAF to zero.
(The bed sits on 6" of concrete so the chances of it moving are small and only one end has moved sufficient to be measured in two years.)
Then I level the blade to the same section of the bed using the DAF.
Then I leave the DAF on the blade and push the mill down the rails to check it's parallel all the way along the mill bed and adjust only the bed bolts that need it.