What is the best way to mount the 4th Axis to my STEPCRAFT CNC?

The most important thing when installing a 4th Axis system to any CNC is to make sure you have the ability to infinitely adjust the distance between the chuck and the tail stock.  This is important if you are not sure what size stock you will be using.  The only time this is not as critical is if you are running the same length stock all the time for every job, then you can install the 4th Axis in a fixed location.

But assuming that you want maximum adjustability, then you should make sure you have a T-Slot Table. installed on your machine.  You will then install the 4th Axis Chuck towards the back of the machine facing the front, along the Y Axis.  Then the Tail Stock will be installed in the T-Slot channels towards the front of the machine facing the chuck.  This will allow you to infinitely adjust both the chuck and the tail stock to accommodate any length stock within your machine’s specifications.