First off, I want to commend the designer on a fantastic machine. I am extremely impressed with how well the parts were designed for printing and fitment.
So here are the specs for what I am running. Machine is using US EMT conduit (24.5mm?) and is a 48"x48", Z is designed for 6". I did not purchase any of your parts but I did follow your list with the exception of the stepper drivers. I am currently running the A4988 drivers (16 microsteps) and the RC7 firmware from this site as the RC8 had “issues” at the time. I have endstops set for MIN on all axis and everything seems to function perfectly.
The problems I am encountering are as follows:
The stepper drivers are running pretty hot to the touch. Motors are fine with regards to temperature.
When the center section passes over the middle of the bed, I get a lot of shaking/jittering in that area. Does not seem to show up in the corner regions. All belts are tight, but the long screws in the center are very loose.
This is the biggie. I am running a pen to print the Crown picture. When printing, the system will have a noticeable surge pattern as it moves. It’s not really obvious, but you can hear it as it moves. One a small print (approximately 75mm across) it barely noticeable. When I scale up the picture, to say 500mm across, it is very obvious. the movement will go from very slow to fast at various area of drawing. I did change the number of steps to accommodate for the different driver, but I cannot figure out what else would be causing this. I am printing over USB via Repetier and also Octopi, both have the same results.
And assistance would be greatly appreciated. Thanks!