Z-Axis Upgrade to an Existing CNC Router

I'm wanting to upgrade the Z-Axis on my CNC Router, it currently is not rigid enough and I'm getting a lot of flex when I cut. I've been looking online at Linear Stage Actuators that I can pick up reasonably cheap, but I'm running into what I believe will be an issue. All the Actuators I have seen come with a metric ball screw, (sfu1605 ball screw, 5mm pitch and 5.08 turns per inch) so my question is can I use the metric ball screw in the actuator for my Z-Axis and continue to use the existing 1/2" 5-start lead screws for my X and Y-Axis's. I know I will probably have to recalculate my driver and stepper for the Z-axis. Unsure of what to do next, any help would be greatly appreciated.

I can't think of any reason why it shouldn't work.As far as the controller is concerned it just takes the numbers you configure it with and applies the correct number of pulses for the distance it has to travel.You clearly appreciate the point and just need to do the calculation to get the revised values.Do keep in mind that you have just started on the merry-go-round of chasing the flex in the machine and the machine you had at the start of this pursuit might not be very much like the machine you have when it concludes.

Thank you for your help, I was hoping that it might me a great alternative to machining one, I appreciate your help, Thanks again.