I think Colin will have to experiment.  Online calculators and books all recommend maximum economic industrial cutting rates, which are generally generally faster and deeper than a hobby workshop is capable of.   So our experience is more of dialling back than going much faster.   I guess experience of Colin’s too-fast problem will be thin on the ground!

HSS is probably out, but carbide and the right material might work well enough.  In ordinary machining, free-cutting metals do well because less energy is needed to cut them and they resist tearing, resulting in a good finish.   When I ran a fly-cutter too fast on free cutting steel the finish went to pot, I think because the metal tore rather than cut.   With carbide a deeper cut often fixes tearing, provided the machine has the necessary power, torque and rigidity, which mine doesn’t.   A high-speed head might do better with a more difficult metal, one tough enough to resist tearing at high speed.  Dunno.

High-speed heads are for spinning small diameter cutters doing delicate work.  Most desirable I reckon, but a specialist tool that will struggle with face cutting and any other general purpose milling for which slower speeds are needed.  (Usually much slower than 1900rpm!  My mill gets down to about 150rpm, and that’s too fast for some jobs.)

Feels like a lot of pratting around.   Like taking a Formula 1 car to Tescos, could be done, but more trouble than it’s worth.  My gut feel is the best answer is to find a slower head for rough work, and get the high-speed one out only when needed.  Sorry!

Dave

No need to experiment I have done it for you ramp it up rather than dial it back.

63mm insert face mill with inserts intended for non-Ferroius will spin happily at 2000rpm on all the common model engineering metals. So if you come down to a 50mm head then you could run at 2500rpm for iron and steel and if you have more available then use it on non ferrious. Go for a 5 insert rather than a 4 insert then you can feed a bit faster for the same given chip load.

See the copies of my MEW articles here and here.

You can also wind it up with solid cutters too.

An insert lathe tool in a flycutter will also run at similar speeds but you need to have it well blanced, downside is your feed rates will be slow a sit only cuts once per revolution

I’ve run the 80mm at 5000rpm on the CNC so not sure where Dave gets his idea high speeds are only for small solid cutters, I’d be running them at a lot more if I did not max out at 5000rpm.

All at 2000rpm with a 50mm dia head, feeds upto 400mm/min