You may know I have two near identical Taig Micro-mills. My first one is well over a decade in age. I use MACH3 controller software running in Win7 and using a USB SmoothStepper with a home made controller. My newer mill is less than two years old and uses MACH 3 as well running in WinXp Pro and direct off the printer port. The controller is a good running CNC4PC controler model CS4PAO-3. The link goes to my review.
I just ran a 2 hour (each) wax carving test between the two machines carving the exact same part. The micro mill bits were both tapered 10 deg 1/8" shank with a 0.005" ball end. There may be slight wear differences between the two mill bits but I don't suspect much.
The old mill produced noticeable better carving than the new machine. Both parts were very good, but the old machine performed better than the new. I also felt it "sounded" much better running the identical code as the newer machine. The difference has to be the SmoothStepper. If you are a CNCer, you know what I mean about the sound.
The difference is the pulses for the steppers is made within the SmoothStepper hardware rather than using timing from within the PC. It really is best practice to use external pulse generation. I think this may be the clincher test I needed.
I just ordered a UC100 USB Motion Controller form CNC4PC. It provides the same functions as the USB SmoothStepper but it is all contained within a plug type case. About $125.00 with shipping. If it does the job like I suspect, I'll get another for my HB2 gantry CNC machine. For now though, I just want to get the best results possible from the newer Taig Mill. It's primary and right now only function is very precise wax 3D wax carvings for my lost wax casting masters.
As I have already said, it has been performing very well, but now I will really see if external pulsing is the ultimate solution. I loved the SmoothStepper when I first used it. I think I will feel the same with the UC100.
I will certainly publish the results in a week or so...