Bingo !!!  
That was it. I changed it to "Exact Stop" and it's fine.

Please explain why, and is that really what you want it to do?

Sage

I just turned on the machine and I am letting it warm up. I am excited now to hear that the exact stop made it work.


 

I remember a long time ago, Brian saying there was some limitation with CV and a 4th axis.

Art said it should work if acceleration rate of the 4th axis were pretty close to what the linear axis are.

Never got a better explanation.

Also not at all sure this is the cause of your problem, but thought it was worth a try.

Greg

Going to Exact Stop fixed the problem.

It worked fine with that simple switch.

So my question than would be, when doing something 3d where you can't use Exact stop if all the axes are moving, I am probably going to have the same problem than ? I haven't done anything 4th axis like this yet. I'll report back when I do.

But as it sits right now I was able to machine a piece of wood using the exact stop as the key to the solution of the dropping Z ( missing steps I guess ).

Thanks
Todd

PS I ll post pictures of the project when I am done.

Yes. I'd like an answer to this too. There are definitely times when you want to use CV mode (I think) and without some hard and fast rule it might - with my poor memory - send me back around this trouble loop again.

Yes, please post some pictures. You had me wondering what you were up to.

Sage

Well toyed around with it more. Mostly making the fixture. I will be cutting a part hopefully tomorrow if all goes well, and will post a picture than.

Thanks again everyone.

Todd

Here is a picture of what I was doing.