I have a situation I am at my wits end with and need some help.
I just converted my manual Sherline 5000 to CNC using HobbyCNC 200 Oz in steppers and their board.
I set it up ala instructions on Mach3(that is what I am using) and the X and Y axes are running just fine. No problem moving those axes to any dimension. Now the Z axis!!!!!! It moves down two or three times the dinemsion called out. Moving up it only moves about half of the dimension called for.( z.250 yeilds z.125 most of the time.) I added helper springs to the axis and it did not help at all. I changed to a belt drive reduction (2.2:1) and it didn't do any good. Backlash is not noticeable.
Does anybody have any idea what may be up with this axis? I really would like to be able to control by programming rather than doing it manually.