Lets give this a shot Will.
I looked at the Amana tool catalog and picked HSS1634 because it is 1/4" 2 flute end mill except for the carbide close to Carbide3d's and I think Amana makes the Carbide3d end mills.
Then their chip load recommendations
and than I worked up a feed and speed excel spread sheet using their 18,000 RPM and their chip load.
Now I also wanted to try that Janka comparison idea with Red Oak to Red Mahogony.
The feed rate equaled 106.7 mm/sec for the red oak, I used the max chip load on the red oak. The Janka conversion resulted in 51 mm/sec feed for the harder mahogony. To try to reach that feed rate I had to reduce the RPM and the mahogony chip load. But, on the wiki shapeoko 3 materials, list for mahogony it shows a feed rate of 1651 mm/min or 27.6 mm/sec and it seems had to justify the 51 mm/sec of the spread sheet as well as the 106.7 mm/sec (4 inches / sec) for the red oak. Granted that I know nothing about this stuff and really trying to learn, I am very confused. Calculated the chip load X's the #'s flutes X's RPM for the Feed Rate. I could accept that I am just too inexperienced to try this exercise.
For the fun of it, here is the brinell hardness numbers for hardwoods and hardened aluminum just to compare how much the Janka scale may relate to cutting metals, not much I presume ( 7hardwood to 75 6060 aluminum).