hi angeltech
the inverter is only set to 60mhz , i will change to 100mhz tommorrow when i go to my workshop , i don't know why i put the ratio of .60 but i thought it might be something to do with the ratio of the motor & spindle pulley diameters ? should this be set to zero  . would i get better results if i had a spindle disc with a single slot as suggested by dickeybird
robert

definately go with the single slot, mach only needs the one. Set the ratio to one.