Boxford 4th axis

[m_c]

Steppers come in 4, 6 and 8 wire flavours, not just 4, it is possible to connect a 4-wire driver to 6 and 8 wire steppers by externally connecting the circuits to a 4-wire configuration, but if you have a 6 or 8 wire driver you cannot use a 4 wire stepper

Which is why I said to physically trace the wires inside the control box. The stepper driver wires should all connect in the same area, possibly to an individual driver, which means you know exactly what wires power the stepper motor.
Then it just leaves the other individual wires, which by tracing, will hopefully connect to a terminal with some form of name to work out what they do.

I would very much doubt that all 8 wires are solely for powering a stepper motor, given Boxford typically only use 4 wire drivers.