so i got my order of end mills for maritool today.
all of them are TiAlN coated 4 and 6 flute end mills, some flat, some ball end, some variable etc etc.
i bought these for steel, so naturally i tried them in aluminium
not really a good idea. they work, but not ideal. the HSS bits are better suited.
in steel they reinforced what i had been thinking about how to run my machine.
1/2" 4 flute variable. runs at 60ipm, .01" depth, full or near full width. anything deeper chatters too much and a bad finish results. very light side cuts are fine as well. coolant seems to not required in this situation. 0.3cfm.
1/4" 4 flute variable. runs at 20-30ipm. .02" depth full width, or lighter side cuts. i need a proper sized collet however. the 6-7mm metric one is too large and the tool creeps out of the holder. runout is hard to control as well because of the creeping. coolant is a good idea here. make alot of noise plunging and leaves a high spot from machine deflection on helical cuts. 0.15cfm.
1/8" 4 flute variable. runs 10 ipm, .12" depth - probably can go deeper. no chatter at almost 1" extension from the holder. plunges well. coolant is ideal here. 0.16cfm.
all these bits are variable flute with small radius's on the corners so they are less prone to chatter and breakage.
so, basically, the 1/8" will be the workhorse for any small work in steel. the 1/2" will be for surfacing and roughing large pieces. i will have to seek out a stubby 1/2" 4 flute to reduce chatter more.
the 1/4" seems to be not really worth having for steel except for deep side cutting. with a proper collet though it might fair alot better. we'll have to see.
i also tried a 6 flute 1/4". its intended for light side cutting. it pulled out of the collet ablout 1mm and snapped off. well, at least it was a $12 maritool and not a $30 niagara like last time. ive had bad luck trying to use these 2 times now, i think i'll stop.