For roughing, I always go across the grain. If you go with the grain for roughing, depending some on the type of wood, you will get these long slivers that will peel off and plug up your dust pick up and can also peel off extra material that is below the finish pass. I generally leave 0.04 for allowance, but less should make for less fuzzies, but keep in mind that with an end mill, it will not be 0.04 (or whatever you set it at) in all places due to the geometry of tool and design.

Again, depending on the wood and grain, running the finish pass with the grain can make for a lot of fuzzies that need to be scraped/cut/sanded off and it's not fun when there's a lot of them. I'll decide more on the kind of grain and type of wood as to whether I run with or across. I'd have to say though that there's more times that I wished I'd ran across the grain when I didn't than the other way around. A new sharp exacto knife and some shaving before the sanding mop is needed then. If your stepover is too high (above 10%) and you go across the grain, you'll get unacceptable scoring lines.

Just finished this one up for a raffle. Across the grain finish pass, 0.0625" BN @ 8%, 5.5 hours, sanding mop and ready for finish.

https://drive.google.com/open?id=0B5...HYwbmJDMDhBcW8