The maximum safe spindle rpm sliding control changes the value too quickly. How do I set the exact spindle rpm value my machine?
Click and drag the slider to one end of the scrollbar. This will set the rpm to 30000 at the upper end and 1000 at the lower end. Clicking on the white area in the scrollbar changes the rpm value by 500 rpm, while each click on the arrow at either end of the scrollbar changes it by 50 rpm. This should allow you to set the correct maximum safe rpm.