I have a need to machine some deep pockets, 6061-T6, pocket is 1.7" wide, 13" long and will be 2.7" deep. I have ordered two new Niagara A337 3 flute 37 degree helix bright finish HSS cutters, one is 1.250" cutting length and the other is 3" cutting length, both are 1/2" diameter. Was going to use a 3/4" drill to remove as much of the pocket as I can first, then manual end mill even more away for a near net size of the pocket and then CNC the finished product. So I think the cutter will only remove about .125" or less from the wall when CNC.

Any suggestions for the feed/speed on the long end mill? right now I am thinking 4500 RPM, 10" IPM and .050" depth of cut. This will take 2 hours with those settings. And that is with the short end mill running at 20" IPM to cut down to 1.125" inches first, then take over at that depth with the long end mill to finish it out.