I recently purchased a omio cnc x6-2200.
I have had it for about 4 months and there are things that just arnt right.

1.I am missing stepps
   I am not sure i have the motors tunned properly. I know there is a formula but i have yet to figure it out. below are the specs to my motors and ball screw
   1605 Ball screw,Diameter 16mm,screw thread pitch 5mm
   X/Y/Z Stepper Motor ： 57BYGH76-3A/150N.cm
   X/Y/Z/A Stepper Drives： YOC556 High performance Digital Stepper Drives
   I want to do everything in inches not mm.
2. if i want to jog the z axis to get zero using a piece of paper i have to go to the settings tab in mach3 and click units to mm or it will just move in the z direction to far and to fast.
any help that can be given will be much appreciated

How to calc the steps per unit can be found in the Mach Manual, also in member docs there is a spread sheet that will do it for you, and there are few others in there  I believe.
But you can also use the Calibrate axis feature of Mach to do it for you.

Suggest you just start by reducing whatever your velocity and accel settings are in half to start and see how it goes. Raise the velocity  until you start to skip and then reduce by 30 %, then start increasing the accel value and reduce accordingly.

RICH

Raymond, i also own an 6x-2200l.  i would love to share notes.  have you gotten everything working correctly?