Where to Z?

Post Reply
Vectric Apprentice
Posts: 67
Joined: Thu Jun 26, 2014 2:21 pm
Model of CNC Machine: Self built from plans

Where to Z?

Post by dme2637 »

I'm wondering where most people zero their machine. The spoilboard or surface of the workpiece. I've always done workpiece but seems it would be easier to do spoilboard. Also contemplating permanently mounting a Z plate at the end of my machine but don't know how to go about making my machine automatically go to the coordinates of the touch plate. Any thoughts or advice would be greatly appreciated!

User avatar
Vectric Wizard
Posts: 5011
Joined: Fri Nov 09, 2012 2:12 pm
Model of CNC Machine: Gerber System 48,Denford Triac Modified
Location: Crossgates, Scotland

Re: Where to Z?

Post by martin54 »

it's mostly down to personal preference, the type of work people do often dictates where they set there Z zero, if you measure your material accurately & use those figures in the software it shouldn't really make a lot of difference.

As for a fixed Z zero position it will depend what control software you are running, this post might help :lol: :lol:


User avatar
Vectric Wizard
Posts: 4050
Joined: Fri Nov 04, 2005 5:54 am
Model of CNC Machine: GCnC/WinCNC
Location: San Jose, California, USA

Re: Where to Z?

Post by Rcnewcomb »

The rule I was taught was, where do you want your error to show up, at the top or the bottom?

If I am cutting out parts by cutting all the way through the material then I zero on the spoilboard because I always want the cut to go completely through regardless of thickness of the material. Not all pieces of 3/4" plywood are exactly 0.75" thick. If I zero on the surface and the material is thinner than 075" then I'm cutting into the spoilboard. If the material is thicker than 0.75" then my parts aren't cut all the way through and I waste a lot of time trying to get them out.

If I am V-Carving or carving 3D then I may zero of the material surface because otherwise the V-Carving may be too deep or too shallow. On 3D if I zeroed of the spoilboard and the material was a bit thinner than I thought I may end up missing some of the detail on the higher parts.
However, after doing this for a long time I prefer to stay with always zeroing on the spoilboard, and ALWAYS using calipers in several spots to determine the thickness of my material if I am V-Carving or doing 3D.
- Randall Newcomb
10 fingers in, 10 fingers out
another good day in the shop

Vectric Wizard
Posts: 392
Joined: Wed Apr 01, 2009 12:15 am
Location: Dunnellon, Florida

Re: Where to Z?

Post by NormanAlbert »

Hi: If I'm doing a 3d carving I prefer to zero on an uncut portion of the material. That way, if I have to stop the job I always have my exact zero point on the work. Make sure you write down the co-ordinates you want to restart at before you move the tool to zero. Norm

Post Reply