Shapeoko Pro XXL using Vetric software V 11.503

I have been trying to cut a 2 sided project the top side cut perfectly then I turned it over and started to run the first profile cut on the Bottom after setting the bit height and turning on my router and hitting run the Z axis over drives in the up direction and engages the height sensor then stops and then starts to cut but it is about .25 in above the work piece… I am Baffled with the issue…

Note: the Z safe is set to 2.30 in above the top side as I am zeroing from the same side ( top of work piece for the TOP and the Bottom for the Bottom side, i.e. same spot )

Post your file. There are a lot of vetric users on the forum. I could not find the specs for the Z-Plus but 2.3 inch retract seems high. You could be hitting the top and losing steps.


In a 2 Sided project it is taking the Home for X, Y and Z from the same (TOP ) side so when you flip it over so bottom side is up and home is now the bottom or the cnc spoil board surface so hence the zero becomes X 0.0 and Y 0.0 and Z is 2.30 which compensates for the 1.5 in thickness of the material and a .5 in of the spoil board so that leaves .30 in for clearance above the material to be worked. The issue is not the clearance of the height of the Z movement something is driving it higher or it loosing the Z zero…

You might give this a try, because I agree with gdon_2003. You should set your safe Z at the height you want the bit to start above the material surface, not necessarily the zero position. So if your material is 1" thick and your safe Z is .5", it will start off at .5" above the material surface or 1.5" above the work bed, regardless whether you zero off the surface of the material or the machine bed. You have your safe Z set for 2.3 so it is actually starting at 3.8" above the bed, because it figures in the material thickness. This is probably causing you to lose steps when you hit the top of the Z limit. If I misunderstood what you were trying to say, I apologize…just my thoughts from what you described.

Are you familiar with Vetric Software?

Yes, I had V-Carve and now Aspire

It is the same as not having to change your Z gaps above the material whether you zero off the material surface or bed…they both factor in material thickness

CC does the same thing whether you zero on top or bottom of material. When you zero Z on the bottom material thickness is more critical because material thickness is calculated as set in setup and the bit will start cutting relative to the thickness. If you miscalculate the material thickness the first cut will cut the depth of cut for the tool plus the error in your material thickness if the thickness is higher than the set material thickness. If your material thickness is less than set no harm but just the extra pass/passes to get to the actual surface of the material. Where is is most prevalent for me using painters tape and super glue. The masking tape is not very thick but it does add to your material height. So I have changed to creating the CC file and before cutting and after mounting the project I measure the material and change in CC and save the file.

I have recently began using the bottom of material thickness to avoid over shooting and carving up my spoilboard. The spoilboard is made to be spoiled but I want to avoid carving it up unnecessarily. The only drawback is for 4 years I would use the jog to go to the rapid position of X and Y and then Z +6mm. If I forget the bit runs into the material. So with all changes you have to get used to it. So I have to remember to jog off the material to do the rapid position of Z+6MM. Simple to do but old dogs learn new tricks very slowly, they can learn but s l o w l y.

I use .2" above and it works fine.

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