Please don’t use Amana’s speeds and feeds shown in the first picture. But you should be safe with the values shown in the second (for all but the hardest of woods). You probably shouldn’t exceed the manufacturer’s maximum speed for the bit or plunge with it unless it’s designed for that. Note that reduction of speeds will likely cause proportional reductions of available cutting (router) powers and increases in machine forces. Also, reduction of feed-rates, depths of cut, and/or widths of cut will likely cause proportional decreases in cutting powers and machine forces. You might find this calculator useful to predict the impact of such changes.
Also, since 1/2" cutters can provide twice the cutting powers (and material removal rates - MRRs) of 1/4" cutters without increasing cutting forces, you might want to monitor your router power draws to ensure that you’re not pushing the routers too hard. With 1/2" cutters, it’s likely that router power availability rather than machine rigidity that will limit stock Shapeoko achievable MRRs.
2019-12-08 Update - @Burly, @Julien
Here’s a “classic” flat center cutting mortising bit. Freud’s speeds and feeds calculator allows entry of speeds up to 49,999 RPM for it.
It appears that this (35,000 RPM maximum speed) Amana bit can also plunge (drill) straight in but will leave a small inverted cone in the center because of it’s center cutting geometry. I’ll check that out.
