ric812:
I am trying to connect TB6600 steppers to the CNC shield. I have 4 NEMA 23 425oz motors. Do the A998 Steppers have to installed top use the step/dir pinouts on the side of the shield?
If you want to use a TB6600 stepper driver for a motor then you should NOT install the A4988 driver for that motor.
I don't know if the shield has appropriate connections for a TB6600 because I am not familiar with the TB6600. Also I don't know if the circuits on the shield can handle the higher currents that a TB6600 would be capable of controlling. It would probably be best not to run the TB6600 motor power (in or out) through the shield.
Actually the shield does not care what is the function of any particular pin - it is just a convenient conduit for the Arduino signals so the important thing is that the Arduino software is configured to send the proper signals to the proper TB6600 pins.
...R