First, I am by no means an expert, just getting started onmy first CNC conversion, but have been doing a lot of research and have found that Gecko's are the cream of the crop. Your specs would indicate needing a driver that can give 56V and 3.1A. The Gecko G251 can do 50V at 3.5A. You would be a tad slower but it is much cheaper than the other Geckos at $69. Other options are the Keling drivers which I have read good things about, and the Chinese TB6560 drivers off E-bay. The TB6560 is only good to about 24V though. Below is a link to where you could buy the G251 or the Keling drives. For the Chinese driver search ebay for "single axis TB6560"