Could you tell me why it's considered bad practice? I had plenty of motors and I figured that double the motors would be double the torque? Plus I have a 22,000rpm router as my cutter so I'm just using the slide on that for my z axis and it needs the two pressure points to keep it nice and straight.
I understand your reasoning but both the TA8435H and TB6560HQ chips have been designed to handle just one motor. A web search should reveal the technical data, design data and manufacturers application notes should you wish to research this in more detail.
Basically, each stepper motor should have its own, dedicated, driver and ‘slaving’ of two axes (within Mach3) is the usual practice when two motors are used to drive together.
However, don’t let this stop you from trying your design ideas – stretching the envelope and thinking outside the box is true innovation but you should perhaps be prepared to run into problems which others before you have already discovered.
Tweakie.