I have a follow-up question that may be related....
I cut a 2-sided maze with a 1/8" downspiral and a 3/8" ball end into 1.25" thick poplar. I found that one side came out quite smooth and almost needed no sanding. When I flipped the board and cut the other side there is now a whole bunch of tough fuzz, in the vertical surfaces (cut with the small end mill) and in the undercut channel (done with the ball end bit) as well.
Same board, same bits, same speeds/feeds, similar pattern, same depth. Only difference was top vs. bottom of board, one was maybe 30 minutes later and the first cut was held with vacuum while the board was held with screws and dowels for the flip side. Maybe it is just the way poplar behaves, although I can not come up with an explanation of the physics.
Any other suggestion for low-cost lumber that cuts clean without fuzz? Sanding inside the channels of such a maze is not really practical.