SainSmart CNC controller:
I went and bought a SainSmart CNC controller. It's all professional and serious, so I thought it would be a great start. I watched various youtube videos of the module to better understand this device and gained some confidence so tried it out. I worked through the various switch settings and arrived at what I believed to be the setting with the best holding power and I was still able to turn the stepper's shaft with my fingers. It was quite strong, but not enough.
To make sure it wasn't the power supply's fault, I bought a lab power supply off Amazon and hooked it up. It read 24V and max current draw was just under 1 amp. With this "bench" power supply, I could still turn the shaft with my fingers.
Rugged Motor Driver:
Next up is the "Rugged Motor Driver" from rugged circuits. I was able to get this shield to work with the stepper motor. I was eventually able to coax the sample sketch to manipulate the stepper into doing things I want. And then I was able to gain confidence in what was happening and I was happy. Happy-ish, anyway, but the stepper would "sing" loudly. Everything seemed ok otherwise, as the stepper remained cool to the touch and the driver chips on the shield were only slightly warm to the touch.
Big Easy Driver:
I purchased one of these for a previous project. The small easy driver was super easy to use for the big one should be, too. What could possibly go wrong? Oh, the smoke. It fell out of the big easy driver. I hooked it up the same as the other two boards prior (and the small driver with 12V prior) and then zzzzzzzzzip pop smoke.
OK so Rugger Motor Driver it is...