Which is easier to machine on a manual lathe 12.9 or EN24 steel?

[compositepro]

Both are easy to machine on a manual lathe

Carbide and a good depth of cut will do it nicely tiny cuts are not your friend with either material En24T and 12.9 drills beautifully

If you are doing it with cobalt m42 bits put a 0.4 radius on the tool and select a feed per ref roughly half the radius but keep your tool sharp

the problem is you are doing 40 which is CNC qty money