Those almost look like Cineik Camera Hot Shoe Handle by CINEIK — Kickstarter
I switched from a 4-flute rougher to a 3-flute to improve chip clearance. Although I use a Trico MD-1200 in lieu of flood (high-pressure flood coolant may do a better job - I don't know). With a 1/2" Maritool carbide 3-flute EM, I can easily cut 0.25" DOC, 2800 RPM, 25 IPM (sometimes push it up to 30) with 80% stepover. However, I reduce the DOC for sloting - usually to 0.125 to 0.1875 DOC.
This is a short video with that approximate cut recipe: http://www.youtube.com/watch?v=h2t0sDBzYmE]Hoggin' Aluminum with Tormach PCNC 1/2" Rougher - YouTube
Now hurry up and get my hot shoe handle shipped