how to set my new acme rods

Hello all, I got a new printer from Geeetech and globally it work ok.... excepted for the z axis,
which is very sloppy in quality, the M8 rods are so off of strait... it barely are usable like that.

It is so bent.... there was or is no chance to make a nice piece with those ugly steel rods

So I buy some 8mm ACME rods to change the existing one, but now I am lost how do I upgrade
the firmware or can I do that with reportier-host

The card is an "Arduino" Ramps 1.4 clone and the drivers are A4988


Thanks to helps me



Marc P.

Sorry for my bad english ...again thanks for your help

Edited 1 time(s). Last edit at 07/21/2015 04:39PM by MammaAiuto.

Find yourself a prusa calculator to calculate the steps/mm from the rod, I also having a bent threaded rod, at the end of it(I didn't notice it) and fixed it after I flip the rod leaving the bent end at top