XYZ probe offsets differ

I’ve found that my XYZ probe has different offsets for X and Y. It’s only .31mm off, but it is off by that much. When I do two-sided multi-setup cuts, this shifts my cuts on both axis, unless I swap my offsets before zeroing the second slide. To be super clear…

I zero the first side as normal off of the front left corner of the material, while the material is registered off of a set of dogs on the left side. After flipping the stock, so that the left side is now the right size, again registering that size against a set of dogs, I zero off of the front right corner, which is the same corner as last time.

I do it that way so I zero from the same point no matter the material dimensions, thus eliminating potential for error.

Now, the questions.

Is this how others are doing this? Is there a better way? Are others concerned about .31mm errors? Is this something Onefinity would consider a faulty XYZ block, that doesn’t meet tolerances? Are there XYZ blocks that you’d recommend?

Why not update your blocks dimensions on the probe page? It’s not cast in stone,Lol

I do that, but I have to change them every time I flip the material, as it requires rotating the block by 90 degrees when I zero the second side on the same corner. That’s a constant hassle to change it back and forth all the time.

That sounds like a pain to do each time. Could you mill the inside of the probe with your machine to make the offset even on both edges? I probe from the same corner each time but would have to change the offset if I used the other corner.

I could, but I’m not very confident in my aluminum milling skills yet. Support told me the expect only a.5mm tolerance on the XYX probes. So, I found this one on Etsy that’s got a .02mm tolerance. Touch Probe XYZ for X-carve and Shapeoko the Perfect 000 - Etsy

I’m going that way.

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One of the reasons I’d like to install an actual probe and not use the plate for X/Y. Probe tips are adjustable and well suited to changing orientation and location, including inside measuring.

What is an “actual probe”?

A 3D touch probe - it’s an active part that measures x, y and/or z of any other surface/object.

Screenshot 2023-08-31 at 1.22.26 PM

Screenshot 2023-08-31 at 1.23.18 PM

Using one will also require a tool setter (OneFinity have announced they have one coming but no details) to measure its length and also measure the next tool(s) to calculate their offsets and know how to move Z.

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This looks very interesting. I’m assuming it triggers as soon as the probe is bent off of it’s vertical axis, not relying on an metal surface to touch off on. Is that correct? If so, why doesn’t everyone use these by default?

Hey Adam,

unlike the 3-Axis Touch probe that is in fact a touch plate, the probe Espressomatic shows is really a probe and the standard tool to give a CNC machine the knowledge about the dimensions of the workpiece.


Because the CNC controller has to support this and since the derived Onefinity Original Series CNC controller does not, it is widely unknown in this forum. This could change with the advent of Onefinity Elite Series featuring the Masso G3 Touch CNC Controller in 2023.

However I believe noone should underestimate the usefulness of the 3-Axis Touch Plate, in cases where your workpiece is simply a rectangular cuboid (and is not a grounded conductor material).

Further reading

Support (works in Masso and most CNC platform), $$, requires a tool setter or touch plate in addition (for tool measurement), you have to swap this out with your tool(s), when that’s done you have to insert it into your chuck EXACTLY as deep as it was the first time - because the controller has its length saved and will calculate a different offset for new tools if its position isn’t the same as when it was originally measured. It’s also best used with auto tool changers because then the length/position issue is taken care of due to the probe and all tools being pre-fixed to carriers that fit the pneumatic chuck.

Anyway, still a big time saver for manual tool changes and since Masso supports it you can have one giant gcode file with multiple tool changes and the machine will pause, move to the change-over location, accept the new tool, measure and then continue.

You can also use these to make a 3D surface map of a workpiece if you want to carve on it without surfacing it (like adding V-carve to something that isn’t flat).

I may have to pick up one of those. Thanks

I see some significantly different prices for touch probes. Anyone here have recommendations?

I also have dog holes that create corners all over my wasteboard surface. I’ve thought of just setting G54-G59 to the corners I want to place my material at. I think this would eliminate the need to zero X and Y completely. Is this an approach that others use?

Masso shows the one in the last photo on their Touch Probe online instructions and there’s a wiring diagram for it in their forum. You can get them from a number of sources on AliExpress or Amazon. Here’s one picked at random:

The first one pictured is from Topcom in Czechia and also looks really nice, especially the quick-release magnetic connector they’ve developed. Products –

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This is how I do most of my work.

Instead of probing like 1f says and measuring probing from the inside of the workpiece, probe from the outside.

This will solve your problem as you only have to pick the correct movement logic

I purchased a Drewtronics probe when I first started my machine build and it is working very well. After dialing in the concentricity I went down a rabbit hole of collecting data on its repeatability, including how this changed with trigger position/probing direction given the mechanism used in these probes. I found it to be well under the stated +/- 5 micron repeatability.

The only drawback for my ATC set-up is its size/length. I use ISO20 tool holders with my spindle, and with my earlier tool rack configuration I was able to place a custom holder for it on my table that allowed me to use it as a ‘tool’ with its own length offset recorded. Now I just manually load it and use it mostly for zeroing X and Y, and use a 0.025 mm metal shim for my Z height.

When funds permit, I would like to try another probe with a smaller/shorter form factor, that may allow me to add it to a custom slot in my tool rack. Perhaps even one that is wireless that better suites this application. Apart from an unnecessary expense, I don’t think having it as a configured tool however saves any time over loading it manually - something I am used to now as part of my workflow. Still, the thought of being able to call my probe with an M6 command is intriguing, if for no other reason than seeing how it works.

As far as setting G5x to set table locations, I would do that for wood projects where I am locating the corner of stock. I am currently exploring aluminum machining and toolpaths, and prefer to use the touch probe for my XY(sometimes Z) zeros for each job. Having said that, and based on my experiments, the repeatability of my homing sensors (and I am sure the IR of the Elite) would definitely allow for very accurate and repeatable use of defined work offsets.

The two I mentioned with links above are some of the shortest I’ve ever seen and very attractively priced compared to so many products out there. They’re both available with M2.5 threading to allow swapping out probe tips easily (different lengths, different materials, etc…) BTW have you see how much wireless ones cost?

I have been looking at probes for quite a while now, on and off since I got my CNC a few years ago. I like the smaller ones, like those you showed/linked, and suppose it is always a bit of a gamble when it comes to what the paper specs are and what testing and use show.

Besides the high cost of many wireless versions/models, I have always been a bit reluctant because … I like wired connections (not based on science or use experience :grin:).

Some, like VERS, have a control board with added functionality and options like an error signal output. I like having some way of Masso knowing if there is an error. Right now, perhaps because I am still relatively inexperienced with machining, I always give my probe stylus a quick tap and check my screen to make sure it triggers. I would probably be even more inclined to do so if ever I did invest in a wireless model.

I don’t have an Elite, but on my Machinist, when I do a 2-sided job, I use the dowel-in-the-spoilboard system recommended by Vectric. That way, you don’t remeasure the zero on the second side at all, just set an arbitrary zero, drill the holes in spoilboard, and cut the second side.

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