what are you missing? design the program and write the code and send me the source and I'll compile it into a PIC :), sell it on ebay... next stop, world domination!!!

Seriously, I use the F877 in my testbed, which has a 4x4 keypad and a 20x2 display (actually 2, one a serial i/f VFD and the other a parallel LCD).

I would have the program have 3 modes:

Mode 1/ show actual speed in RPM (allowing input of a # pulses/rev value)
Mode 2/ Given a material type & a tool diameter & # flutes (or for a lathe, material type and diameter) and return the recommended spindle speed and feed rate
Mode 3/ Given a tool diameter and current speed show the surface cutting speed in m/min