I just started building a Graber i3. I’m thinking of using 8mm lead screws instead of the 5mm threaded rod for the Z axis. Does anyone know if there’s an existing set of files to suit for the X idler and X motor mount constructions before I charge ahead and layout my own variant?
8mm lead screw is too stiff for Graber i3. Stay with 5mm but stainless. It is harder and more accurate than metal one.
OK, I’ll have a hunt around for the 5mm. It’s proving difficult to find near me. Pardon my ignorance, but why is the rigidity an issue with the lead screws?
@Mark_Rehorst , if the screws are too thick, any imperfections or bends in them can translate to the 8mm lead screws. A lot of people swapped to 5mm, because even if you get bends your screw won’t overpower the 8mm linear rod.
First time hearing 5mm threaded rod stainless steel…
@ThantiK that’s it! @Step_Cia It is available in every metal shop. RepRap 3d printers based on i3 are a little bit too flexible for 8mm threaded rod 
Now I just want to build 2 of them — one of each to compare 
Based on the comments, I’m going to assume that there’s no point hunting for some variant files for the 8mm.
I3berlin has 8 mm trapesoidal screw. Il go with them,they are cheap on banggood.
I have 3 reprap printers with 5mm screws. I got rid off 8mm threaded rods long time ago