Hybrid Manual/Stepper Control

Hi Folks,

I have a bit of an odd use case. I have an RF45 clone machine, and given the position of my z crank, I don't ever want to touch it, and would prefer to use the Z controls of LinuxCNC. However, I want to maintain manual control of my X and Y crank for the occasional manual operation.

Is there a reasonable way to make LinuxCNC control my Z, without getting unhappy about following errors on my X and Y, without having some kind of "modal" behaviour, where it "snaps back" to the commanded position when I exit that mode?

 
One option is MPGs, you could install two MPG encoders.

forum.linuxcnc.org/27-driver-boards/4698...7i96s?start=0#252760

I made a lathe with manual control of two axes simulatively, although apart from the servo motor as the main spindle I didn't have another axis as in your Z that could do its thing while these two are moved manually as I understood. maybe something in this topic can help.

Thanks for the replies! I have considered putting independent x/y MPGs somewhere on the machine, but it doesn't quite scratch the itch I'm trying to scratch. 
My background is a manual machinist, and I wanted to add some CNC capability to my arsenal, even if that came at the cost of being able to do manual machining the way I used to. That said, there's no substitute from the feedback you get from turning the cranks, when you just need to make a quick slot, face a part, etc.
It seems like LinuxCNC (appropriately) is really intended almost exclusively for the CNC use case. 

Why not just close linuxcnc when you want to do manual machining?

The z-axis is supposed to be still usable, because it is heavy.