I'm looking for a VMC to work with aluminum, brass and soft steels. Haas has the vf2 with the option 8100-rpm or 10000rpm spindle and I'm not sure if the cost of the upgrade to 10000rpm is worth it. What would be the main difference?
It appears they run the same motor. If you're cutting aluminum or steel with small end mills you'll use all the RPM. If you're doing production it's a no brainer to get the faster spindle.
The 8k rpm machine will have more torque but for what you are using it for, I would definitely upgrade to the 10k spindle. The 8k spindle is the same as the 10k spindle so you won't need to exchange it for a 10k unit. FYI: We have replacement spindles for all VF machines if you happen to need one. $2,995. All RPM's thru 12k, 208-888-9236.
Go with 10K. I run 1" insert endmills at 12K in aluminum all day. I do believe however that it is nothing but a parameter and can be purchased later. Your HFO may be able to better answer this.