2-Sided Set Up and How Z-Zero Bottom Actually Works

I’m looking to make a simple 3D component carved through the material. I’ve set Z-Zero off the same side in a 2-sided V-Carve project. Once at the Multicam, the first side carved correctly (z-zero was on surface). Next, I turned the material over and reset both max depth and surface depth (z-zero was now on spoilboard), but the bit hovered over the material similar to what @rablack97 and @Kentamanos discussed in 2015 (different enough, I thought, for a new topic).

Having read what I could find on Talk and Vectic forums, I’m looking for feedback and help with the intuition of Z-Zero on the bottom, specifically in the context of a 2-sided 3D component where a waste material is used for dowel holes. Here are my questions:

  1. Once I’ve turned the material over (with Z-Zero now on the bottom), am I correct that I simply need set the max depth? That is, the surface depth will be assumed from material thickness.
  2. If so, does it store my previous surface depth, such that I need to remove the previous surface depth to prevent interference?
  3. What if I had the stock on top of a waste material that was used for dowel holes? Is the best solution to just set my new max depth (for the bottom cut) to the surface of the waste material?
  4. More generally, why did the bit hover over the material?

Many thanks in advance for your help.

This is not an area I know very much about, but am willing to look at it with you. I should be at DMS beginning midday today if your schedule would permit meeting to discuss. If not, when might work?

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Thank you for your reply, and sorry for the delay. I appreciate your help with this and would like to meet. I’m available this afternoon and evening, any time tomorrow, and Sunday before 1p or after 8p. Would any of those times work for you?

This evening might work but need to confirm. Will you be there anyway or just if we schedule to meet?

Just if we schedule. I’ll be available and just need about an hour notice.

Let’s shoot for 7pm today.

Sounds great. See you then. Thanks!

Adding a conclusion for this thread … a “new to me” feature of V-Carve is the 2 sided setup mentioned by the OP. You access this in the Job Setup area by selecting “Double Sided” as the Job Type. The OP then selected the “Zero off same side” in the Z Zero Position area. Given those choices, here’s what works:

When you carve the “top” side, you will set Z-Zero in the traditional fashion and the gcode will be processed normally with Z-zero being at the top surface and the cutter moving from zero to a positive number as it cuts into the surface.

When you turn the piece over and carve the “bottom”, you will set Z-Zero on the piece that the work sit on (spoilboard or a special base to allow proper registration of the work). The gcode for the “bottom” will then start from a negative number and become less negative as it is cutting into the work.


Carve a 1.5" thick piece of wood.
Top: set Z-Zero at top surface of work. Gcode has bit travel above the work at -0.2" or similar height and then travels past zero into positive numbers as cutting happens. If your deepest cut is 0.75", then the Z will be at +0.75" when that point is reached.

Bottom: set Z-Zero at the base of the work (easiest way is to set on the surface that the work will sit on). Gcode for the bottom cut now has the bit travel at -1.7" which is 0.2" above the 1.5" thick work. The cutter then travels down to and past -1.5" as it cuts. If your deepest cut is 0.75", then the Z will be at -0.75" when that point is reached.

Now that all of that has been said … if you select the normal “Material Surface” option instead of
“Zero off same side”, things are more normal in that in both cases you work from the upper surface of whichever side is up at the time.