I was making those turners' cubes, from 2 inch aluminum blocks
(6061).

I used a 1/4" end mill.

After making about 4 or 5 cubes, the end mill broke.

My question is, how much life expectancy shoudl I expect from a 1/4"
end mill?

Carbide?
HSS?

My parameters are something like

2,000 RPM
6 IPM
Flood coolant (I do not always do a perfect job at directing it, but I
always try and spray it from all directions.