VFD for series 1 bridgeport

Hi Folks,

I've been lurking on this list and have just acquired a Bridgeport
Series 1 cnc that I will be retrofitting with some new steppers,
gecko's and EMC.

After some searching of the archives I noticed it is recommended to
have the G210's modified for use with Nema 42 steppers. Do I have to
purchase these directly from Gecko?

The machine is missing the air-powered spindle control. I know very
little about how these devices work. Thinking out loud, would it be
possible to build a stepper-driven speed control that could be
interfaced with EMC? The gentleman I bought the machine from
suggested that I also use a VFD with the system. I'm not sure why I
would need to.

Could anyone tell me where I could find parts and manuals for these
machines?

Thanks,
Bob