Buying mid '90s Fadal 4020 and upgrading to 5 axis

I'm planning on buying an older 3 axis Fadal 4020 and converting it to 5 axis with a trunnion. The goal is to machine precision impellers (so will need to do simultaneous 5 axis machining).


This is for a hobby shop so cycle time is not critical, but part accuracy is.


I'm eyeing some 3 axis Fadal 4020's from 1995-2000. Most seem to have CNC 88HS controllers. Is this the right machine for what I need?


What sort of issues might I run into with an older Fadal?


Are there following error issues with the old fadal controllers? Is it worth it to upgrade to something like Calmotion?


How difficult (and expensive) is it to convert a 1995 a axis Fadal 4020 to 5 axis? Would I just need the additional 2 servo amps or does a bunch of other stuff likely need to change too?


What kind of accuracy can I expect with an old fadal 4020? This obviously depends on condition and a bunch of variables but I'm just looking to set my expectations. Like is holding +/-0.001" reasonable to expect? +/-0.0005"?