After reading thru some of the posts on using the touch plate for edgefinding, I would like to recommend using a laser center\edge finder. See this link;
I find it much more useful for referencing X,Y on a complex 3D work piece. It fits in the collet. stick with the single DOT version. The cross hair variants tend to have wider lines making accurate placement more difficult.
I’ve been using this for years.
I bought one for ~10 dollars from amazon, measured the offset from my spindle xy0, and wrote a macro to adjust my xy zero point. Mine is only accurate to about +/-.5mm, but its totally fine for any sheet goods.
Just look up something along the lines of red cross laser module.
I never knew where to find the more accurate ones, so thats cool.
That’s one that I had looked at, but haven’t yet tried.
@CedarMtMandolin on another machine I had I did a setup just like you described where the laser was offset. It worked really well.
What you need to remember is that there’s a width to the beam so in my experience it’ll never be as accurate as a digital probe or a touch plate, but you can still dial them in and get them really accurate.
My use case was just quickly finding the corner of a piece of wood. Typically projects I’d zero to that way I was using oversized stock so the laser was fantastic for a quick and fast zero.
Projects where I really needed to probe exactly where a piece was would have me breaking out the digital probe.
Yep, its great. Been using it for several years. Many times I like to used the center of the work piece as the XY zero. This laser allows you to easily set the dot on a center mark on the work piece or for that matter any other feature or mark that you want to use as the reference.
I agree with your comment regarding line width for the cross-hair variant of the laser center finder from SDA (Link in original post) BUT the DOT variant comes with polarizing lens that allows you to reduce the dot size substantially and get a very accurate XY zero reference. I do a lot of Mother of Pearl inlay work using 0.010" end mills and the laser center works perfect. I build string instruments and it enables locating a reference point on a complex 3D shape a breeze.
I didn’t know that a good laser and polarizing glasses would do that.