Swede, according to my machinist's handbook, in steel you start to see the benefits of HSM at a "surface speed" or cutting speed of 500 m/min. Cutting forces gets significantly lower up to about 1000 m/min. Surface quality improves up to about 800 m/min, then stabilises.
This means that with a 1/8" cutter you'd have to run it at slightly above 50k RPM to start to see the benefits of HSM. The book also says that HSM in steel is difficult because of the lack of suitable tools and the very high spindle powers required. Ceramic or CBN (Cubic Boron Nitride) cutters is the most promising cutter materials (this book was printed in 2000).
Everything from the book, I have no experience whatsoever.
Arvid |