I have a hydraulic that the hydraulics are shot .I would like to convert it to all electric .Has anyone done this ? Could you share your ideas? Is there any build threads ? Machine is an old Elliott grinder ,parts for the machine are non existent . I welcome all and any ideas.Thank you all.

We have 2 cylindrical grinders that use to be hydraulic that are now CNC and 1 more in the works. 
We ripped out all the junk, mounted a ball screw to the traverse and grinding wheel travel, and added a control panel. 
Frequency drive on the spindle that rotates the part.  Didn't go with one for the grinding wheel, but that's an option. 
I also made a completely custom program to make it conversational; utilizing a completely custom screen and MacroB.
Very convenient for setting up new jobs quickly and making changes quickly. 
We also added an in process measuring device that integrated rather easily.

I'd be happy to assist further, just let me know what you're looking for.

https://www.youtube.com/watch?v=eJlMbHJ6IPM
At 40 Seconds into this video you can see the custom screen that I made.

My idea is to use a length of timing belt attached to each end of the table with a servo in the center to drive the x axis , add a ball screw and motor to drive the y axis in and leave the z  manual . I would like to use a proximity  sensor or mechanical roller tipped switch ,in the table center to reverse the x axis drive motor every time the control sees a signal from sensor  .And using the original two end stops to adjust x axis travel . That same signal would be used to make the y axis motor move the table in . I would also like a potentiometer  to be able to adjust y axis feed amount . I also need a feed hold button to start and stop the machine motion . I could handle doing all the mechanical work . I have converted to machine to cnc .But I have no idea how to implement the control for this project .

Sorry I didn't mention this is a surface grinder .

I'm sure what you want to do can be done using LUA (Mach4's Scripting Language).   I get my tool changes working in LUA and have my control panel script already finished; so I don't mess with LUA a great deal anymore. 

If I need to do something like you're asking, I would just get the industrial version of Mach4 and use MacroB.  Much easier to program and it's G Code. 

That being said, is there any particular reason you still want to use switches to set the machine travel limits? 
It's going to be CNC after you add motors and ball screws to it; let the machine do the work. 
Instead of moving switches, make a custom screen (Sounds scary but it really isn't bad).  Add DROs to the screen for your X Left, X Right, Y Start, Y Finish, and your feedrates for each Axis; then use those values to traverse until finished then wait for the operator to manually move the Z and start again. 

So its not that I want it to be cnc as much as I want it to run automatically the table moves back and forth now but the indeed is hydraulic and dose not work . So I want to automate it where I could manually dial down .005 and let it run till the machine sparks out then be able to stop it  . Not full cnc but an electric conversion .Trying to keep it simple if that's possible . I guess I could use a mill profile and edit the screen to fit my needs and write some programs for the x and y movements . I've ran some automatic grinders where you move the table by hand to where the wheel passed the part in y+ pressed a button and it stored that location then you ran the y- axis till the wheel passed the the part pressed the button and it stored that location .Them you were able to just turn the x table feed on and it would run between the two points you set .That would be nice .And simple.

That's kind of what I was getting at. 
You should be able to do that with X+, X-, Y+, and Y-. 
Jog the machine to each position and then add a button that will store that position into the corresponding DRO.
You can also add DROs to be able to set your Y increment per pass, X feedrate and Y Feedrate and make it do exactly what you want. 

You can do this in a macro and a button press, it will work but I'm sure it isn't the best way to do it. 
You can't exactly stop the execution of a Macro without having some funny things happen.  You may have to use co routines to do it "Correctly".

Someone smarter than me should be able to answer that for you.   

I'm testing some stuff just in a macro with a button to execute it.  It is working ok; but when you try and stop the execution entirely, it does weird stuff.  So, as long as you just let it finish, you should be good lol.  Again, not the best way to do it I'm sure; but it works.

MacroB is very awesome if you're willing to get the industrial version.  But, it sounds like you want the easiest way to get this going and that's just fine.

So its not that I want it to be cnc as much as I want it to run automatically the table moves back and forth now but the indeed is hydraulic and dose not work . So I want to automate it where I could manually dial down .005 and let it run till the machine sparks out then be able to stop it  . Not full cnc but an electric conversion. .Trying to keep it simple if that's possible . I guess I could use a mill profile and edit the screen to fit my needs and write some programs for the x and y movements . I've ran some automatic grinders where you move the table by hand to where the wheel passed the part in y+ pressed a button and it stored that location then you ran the y- axis till the wheel passed the the part pressed the button and it stored that location .Them you were able to just turn the x table feed on and it would run between the two points you set .That would be nice .And simple.

Firstly thanks. I wanted to make a similar plan for a grinder. I like this idea, and it helped. Thank you.