Looking to convert my Smithy Granite 1340 to a CNC with the Black Box. Has anyone had luck running 4A Steppers with the Drivers that come on the Black Box system?
Amperage is but one parameter Check all the parameters, or provide a motor datasheet Coil Voltage: ideally 3-6v Inductance: Ideally under 10mH Current 1.2-4A If it doesn't meet these specs perfectly, provide the specs, we'll be able to tell you what to expect 4A is the peak value for the motor (exceed that and the motor gets damaged) - most steppers run much smoother and nicer well below their maximums, but even then, BlackBox has 4A drivers.
10mH is way too high.. that will kill your torque at higher speeds.. 2 to 5 is preferable. I picked up these which run 2mH when wired in bipolar parallel. https://www.amazon.com/gp/product/B00Q62MBHQ/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1 That said.. for a milling machine.. you might want to bump up to Nema34's and I double the BB would support anything that large.
Generally speaking a lower-inductance NEMA34 is gonna give better performance over a higher-inductance NEMA23 for the same torque range, at the expense of typically higher current draw and higher voltages required. I used NEMA34s on my mill conversion: Grizzly G0758 Benchtop Mill Conversion The bigger issue with combo mill-drills is swapping over spindles, reorienting coordinate systems, etc. It's usually more than grbl can take very well, unless you're happy to spend a lot of time unplugging and replugging cables (lathe Z to mill X, lathe X to mill Y, etc) when you move from one to the other. To run it as a true mill-turn with static and live tooling is (sort of, relatively speaking) simple, but beyond the capabilities of grbl as well. I'd spend a lot of time researching how other people have converted their mill-drills before deciding anything in particular about control firmware or motors. Look at the larger picture first.
