The TB6560 is not a very good choice. I would suggest that since you are using an Arduino and CNC shield, I believe that the shield has provisions for using external stepper drivers rather than the plug-in DRV8825.
I would recommend the DM542T from Stepper Online. I have these on a machine I built and they work really well. The cost more, but they have mid-band resonance dampening, idle current reduction, 4.2A and 50V capability. They are very very smooth. I believe they are made for Stepper Online by Leadshine. They cost about $33 each from Amazon. The thing I like about these are they work exactly as advertised with no monkeying around.
https://www.amazon.com/STEPPERONLINE...+driver+DM542T
If the DM542T is out of your price range then the TB6600 drives are cheap and a better choice than the TB6560. On my machine that has the DM542T's, I started out with TB6600's like the ones in the link below. I like individual drives for replacement ease. The TB6600's worked fine, but they can only be driven to about 40V. I used 36V and did not have a problem. I replaced them only because I wanted more speed and was going to up the voltage to 48V. At 36V the TB6600's worked fine, but they are not as smooth as the DM542T drives, but are a lot cheaper at about $8 on ebay. Takes a month to get them though. They also have some issues in regard to how they are made and setting VRef for the current. Basically the problems limit them to something less than the advertised 4.5A, but for my application I was looking for only 2.8A. See this thread for an explanation:
http://www.cnczone.com/forums/steppe...ml#post1979892
This is the type TB6600 drives I have used.
https://www.ebay.com/itm/4-5A-TB6600...IAAOSw4shYBx~-
Bottom line is that the TB6600 drives are the lowest price/quality drives I would ever use now. I did start out on my first machine with TB6560 drives, but the TB6600's are a step up, and the DM542T drives are very good. Stepper drivers are definitely a place where you get what you pay for.
Note: I also have DRV8825 drives on my 3d Printer and they are great little drives, but no match for a motor that needs more than about 1.5A.