Touch probe usecases


With all the enthusiasm around the release of the touch probe, it got me thinking about how useful it would be for me, so here’s a couple of very basic/naive questions that I can’t seem to find definitive answers for in the other threads:

  • what are the most useful cases where using a probe is significantly more efficient/convenient than touching off manually ? I mean touching off Z axis takes maybe up to half a minute overall. I can see how reducing that time matters for people using their SO for semi-professional use, but for a hobbyist use ?..
  • what kind of jobs require finding X/Y edges with high precision ?
  • how is the thickness/length/width of the probe compensated in the probing sequence in CM ? Is it all transparent to the user ?
  • how do you introduce the probing step in your workflow when you have a dust shoe ? I often touch off with the dust shoe down (a piece of paper slides underneath just fine), so I am wondering if it would turn out to be impractical to lift the dust shoe each time.

In other words: please help me rationalizing my touch probe lust!


Check out Winston Moy’s excellent video ( about using the probe in setups where you have to use different endmills and need exact alignment. That should clear up some of your questions.
high precision X/Y finding is useful if you have to recover after a power outage or after changing a broken endmill where you might have lost a few steps or your X/Y zero completely.


Good questions all…

As I understand it, this is transparent to the user if you’re using CM. CM is more a g-code interpreter than a gcode sender. If you peek under the covers you’ll see it’s doing quite a bit of it’s own thinking (apart from your gcode) and knowing the offsets of the touch block are among those.

All the jobs! But seriously… any job with multiple tools used would in theory benefit from it, specifically if you had to for some other reason rezero mid job. Though honestly, since CAM all measures from the centerline of the spindle (technically), as long as you don’t monkey the gantry out of whack while changing bits, in theory you don’t need to rezero x/y for multi-bit jobs.

Honestly, high-precision and rapid zero’ing of the Z-Axis is (IMO) the best use of probing. I hooked up manual probing on mine a while ago and now any time it flakes and I have to prob manually I feel like the stone age :slight_smile:

It looks like the C3D team put together a REALLY nice package over all (with the integration with CM and LED and build quality).


Finding the edges would be useful if you’re engraving a piece that’s already cut to size, but I’d guess the most common use as suggested above is for multitool or multistep operations where you either need to remove the piece between operations or need to change bits but maintain an exact starting location without hoping the machine didn’t miss a few steps somewhere.

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Which is why I can’t see spending $120 on a touch plate. I bought mine for $15 on Amazon. Of course it does not do X and Y, only Z. But I have never had the need to probe to X and Y.

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Thank you all for the insights. So being robust to mishaps in multi-tool jobs seems to be the key usecase, and lazyness/productivity another good reason :slight_smile:

If anyone using a Suckit dust shoe AND a probe regularly could confirm whether raising the shoe / probing / lowering the shoe each time does not get old after a while, I can see myself pulling the trigger (once they are back in stock, that is).

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My next upgrade will likely be the new suckit boot with the bit change slot for this reason.

Double sided or multi-sided window machining jobs where the stock has to move or change orientation benefit from this accurate X/Y recalibration.


While the touch probe seems cool, I’m not sure how much real use I would get out of it. The thing that interests me more is a tool length probe for my SO3 like the one on my Nomad. I feel like the would be a lot more useful and would be around the same cost or less to produce. Has anyone tried to DIY a tool length probe on their SO3?

Not on my SO3, but on my SO1 I drilled a hole through the wasteboard, and mounted a Z-axis limit switch there intending to use it as a tool length sensor (then I got an SO2 and had to do those instructions and I’ve since given away my SO1).

Daniel, this is exactly what I was thinking about. However my concern is that even with the new Suckit shoe, the carriage mounts would still be in the way, hence need to be unfastened/raised/lowered/re-fastened.

You just need to be able to clip the lead on so I doubt it’ll be too difficult.

I find that with my Dewault being mounted with the spindle lock on the right side that I still have to remove the Suckit base. I can change a bit without moving the arms, but i typically raise the right hand side when changing bits just to make it easier. I also have the EV-Guide shoe, and I can change bits easier on it. I just think the Suckit works a little better. But they are both good.

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