Hi,
my spindle can do 24000 max, I have to set feeds to match. If my speed was out by 10% then my chip load would be out by 10% as well...so what, I'm never that close to the absolute limit.
With the small tools I often use I would like to go faster but I can't and I'm not spending the bucks to do it either. The job will complete somewhat more slowly at 24000 but it will complete
and I'm happy.
Likewise with my high torque spindle (max 3500 rpm, 6Nm cont) if my feeds and speeds are within 10-20% of theoretical best that usually enough.
Back in the old days before CNC that old Bridgeport had a number of ratios, you selected the speed closest to what you required and got to work. Are you trying to tell me that all those jobs I did with manual mills and
lathes were compromised because I did not have the exact speed ratio available? Of course not, provided the surface speed is within 20% of the recommended for that material you can always find a feed that worked well.
I have found that using pressure coolant to clear the cut zone of chips to be a bigger determinant of success than having the exact speed and feed.
Craig