Hi Gary, my 6040 are not too fond of deep (long stickout) cuts with any 2 flute cutters. 1 flute seem to be much more in harmony with the rigidity, on my machine at least. The cutters I prefer, are from sorotec.de, 1 flute alu end mills. They stay sharp forever, and dont break easy.

Just my thought on what have worked best for me.